Super-precision angular

contact ball bearings:

High-speed, B design,
sealed as standard
S719 .. B (HB .. /S) and S70 .. B (HX .. /S) series
 Contents

SNFA is now a part of the SKF Group.

Our new, super-precision bearings are
A. Product information C. Product data

built on the combined expertise of SKF SKF-SNFA sealed super-precision Bearing data – general. . . . . . . . . . . . . 20
and SNFA, using the best technology angular contact ball bearings in the Boundary dimensions . . . . . . . . . . . . . . 20
from each. S719 .. B (HB .. /S) and S70 .. B Chamfer dimensions . . . . . . . . . . . . . . . 20
(HX .. /S) series. . . . . . . . . . . . . . . . . . . 3 Tolerances . . . . . . . . . . . . . . . . . . . . . . . 20
The result is leading-edge products. In Bearing preload. . . . . . . . . . . . . . . . . . . 21
addition to the most comprehensive The assortment . . . . . . . . . . . . . . . . . . 4 Bearing axial stiffness . . . . . . . . . . . . . . 25
assortment of state of the art super- High-speed, B design bearings. . . . . . . . 5 Fitting and clamping of bearing rings. . . 26
precision bearings, customers now have Bearing series . . . . . . . . . . . . . . . . . . . . 5 Load carrying capacity of bearing sets. . 27
access to the advanced modelling and Bearing variants. . . . . . . . . . . . . . . . . . . 6 Equivalent bearing loads . . . . . . . . . . . . 27
virtual testing services that are at the Single bearings and matched Attainable speeds. . . . . . . . . . . . . . . . . . 28
core of SKF’s technical expertise. bearing sets. . . . . . . . . . . . . . . . . . . . . . 7 Cages. . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Seals . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
This unique capability – the most so- Applications . . . . . . . . . . . . . . . . . . . . . 8 Materials . . . . . . . . . . . . . . . . . . . . . . . . 29
phisticated in the industry – enables Heat treatment . . . . . . . . . . . . . . . . . . . 29
super-precision bearing customers to Marking of bearings and bearing sets. . . 30
go beyond bearings and look at all as-
pects of their application.
B. Recommendations Packaging . . . . . . . . . . . . . . . . . . . . . . .
Designation system . . . . . . . . . . . . . . . .
31
31
Bearing selection. . . . . . . . . . . . . . . . . 10
With core competencies in bearings, Product tables. . . . . . . . . . . . . . . . . . . . 34
seals, lubrication, mechatronics and Bearing arrangement design. . . . . . . . 11
services, your SKF-SNFA team is poised Single bearings. . . . . . . . . . . . . . . . . . . 11
to partner with you to meet the require-
ments of your next generation of
Bearing sets. . . . . . . . . . . . . . . . . . . . . .
Type of arrangement. . . . . . . . . . . . . . .
11
12
D. Additional information

machine tools. Application examples. . . . . . . . . . . . . . . 14 Setting the highest standard for

precision bearings . . . . . . . . . . . . . . . . 42
SKF – the knowledge engineering Lubrication and maintenance . . . . . . . 16
company Sealed bearings. . . . . . . . . . . . . . . . . . . 16 Other SKF-SNFA super-precision
Grease lubrication for bearings . . . . . . . . . . . . . . . . . . . . . . . . 43
open bearings . . . . . . . . . . . . . . . . . . . . 16 Super-precision angular contact ball
Running-in of sealed and open, bearings in the 718 (SEA) series. . . . . . . 43
grease lubricated bearings. . . . . . . . . . . 17 Super-precision angular contact thrust
Oil lubrication for open bearings. . . . . . . 18 ball bearings for screw drives. . . . . . . . . 43

SKF – the knowledge engineering

company. . . . . . . . . . . . . . . . . . . . . . . . 46

2
SKF-SNFA sealed super-precision A

angular contact ball bearings in

the S719 .. B (HB .. /S) and
S70 .. B (HX .. /S) series
When contaminants, such as wood dust or Ready-to-mount sealed super-precision Machine tool design is becoming increas-
swarf, get between the balls and raceways angular contact ball bearings in the ingly complex, particularly for multiple axis
of a precision bearing, damage in the con- S719 .. B (HB .. /S)1) and S70 .. B (HX .. /S) machining centres. Exceptional demands
tact areas is almost inevitable. When cutting series are characterized by: are placed on the main sub-assemblies such
fluid enters the bearing, it reduces the as the drives. SKF-SNFA sealed super-pre-
­effectiveness of the lubricant, making the • high-speed capability cision angular contact ball bearings provide
bearing susceptible to corrosion, higher op- • high stiffness optimum performance in applications where
erating temperatures and accelerated wear. • extended bearing service life there is a need for high reliability and super­
The end result of both of these scenarios • low heat generation ior accuracy. The bearings are filled with
is high maintenance costs combined with • compact cross section high-speed grease. Non-contact seals keep
lost revenues from unplanned downtime the grease in and contaminants out of the
and lost production. bearings, with the lowest possible tempera-
SKF-SNFA sealed super-precision bear- ture rise and without compromising speed
ings can virtually eliminate the problem of capability.
premature bearing failures resulting from These relubrication-free bearings are
contamination. Where open bearings with particularly suitable for metal cutting and
external seals have been previously used, woodworking machines.
sealed super-precision bearings provide
superior performance.

1) Where applicable, designations in parentheses and italics refer to the corresponding SNFA equivalent.

3
The assortment

Sealed angular contact ball bearings in the The bearings are manufactured to two Bearings in the S719 .. B (HB .. /S) and
S719 .. B (HB .. /S) and S70 .. B (HX .. /S) tolerance classes and accommodate shaft S70 .. B (HX .. /S) series, like all angular con-
series have now been added to the SKF- diameters ranging from 30 to 120 mm. tact ball bearings, are nearly always adjust-
SNFA assortment of super-precision bear- Those suitable for universal matching or ed against a second bearing to balance the
ings. To accommodate the diverse operating mounting in sets are produced to three counterforces. To accommodate increased
requirements of precision applications, preload classes. The bearings are fitted, loads and axial loads in both directions, the
bearings in these series are available with standard, with a seal on both sides. Bear- bearings are used in sets consisting, typic-
three contact angles and two ball materials. ings without seals are also available. ally, of up to four bearings. Matched bearing
sets with a special preload can be supplied
on request.

SKF-SNFA super-precision bearings

in the S719 .. B (HB .. /S) and S70 .. B
(HX .. /S) series replace SKF high-­
precision bearings in the S719 .. B
and S70 .. B series respectively, and
SNFA super-precision bearings in the
HB .. /S and HX .. /S series respectively
(† Setting the highest standard for pre-
cision bearings, page 42).

SKF-SNFA sealed super-precision angular contact ball bearings: High-speed, B design

Features Benefits
• Ready-to-mount • Shorter mounting time
• Non-contact seals • Prevent entry of contaminants, relubrication-free, extended bearing service life
• High-speed grease • High-speed capability, good thermal stability
• Maximum number of very small balls • Provide a high degree of rigidity
• P4A or PA9A tolerance classes • Superior running accuracy, short running-in time
• Optimized chamfer design • Facilitated mounting
• ISO 19 and 10 Dimension Series • Compact cross sections
• Asymmetrical inner and outer rings • Accommodate radial loads, and axial loads in one direction
• Lightweight phenolic resin cage • Low friction, high-speed capability

4
High-speed, B design Bearing series
bearings The assortment of super-precision bearings
A
Super-precision single row angular contact presented in this brochure includes two ISO
ball bearings in the S719 .. B (HB .. /S) and Dimension Series:
S70 .. B (HX .. /S) series are designed for
high-speed operation and are best suited for • the extremely light 719 (HB) series
light load and low temperature operating • the light 70 (HX) series
conditions.
Features of B design bearings include: Bearings in both these series are suitable
for high-speed operation and tight radial
• asymmetrical inner and outer rings mounting space. If increased rigidity is re-
• a high number of very small balls quired, bearings in the 719 (HB) series are
• a lightweight phenolic resin cage used instead of bearings in the 70 (HX) ser­
• an optimized chamfer design ies, as they contain the greater number of
balls, relative to their bore size. Bearings in
The asymmetrical bearing rings enable the the 719 (HB) series also accommodate a
bearings to accommodate radial loads, and larger shaft diameter, relative to their out-
axial loads in one direction. The outer ring side diameter, when compared to bearings
shoulder-guided cage is designed to enable in the 70 (HX) series.
good lubricant supply to the ball/raceway
contact areas. The shape of the chamfer of
the inner and outer rings is optimized for B design bearings for high-speed operation and
improved mounting accuracy. As a result, increased rigidity
mounting is not only facilitated, but there is
also less risk of damage to associated com-
ponents. When compared to other angular
contact ball bearings in the 719 and 70 ser­
ies, B design bearings have the greatest
possible number of very small balls for in-
creased rigidity.
A non-contact seal is fitted, standard, on
both sides of the bearing outer ring. The
seal forms an extremely narrow gap with
the cylindrical surface of the inner ring
shoulder.

When increased system rigidity is required,

bearings in the 719 (HB) series accommodate
a larger shaft diameter for a given outside
Optimized design of bearing ring chamfer to diameter, compared to bearings in the 70 (HX)
Non-contact seal for high-speed operation facilitate mounting series.

a°

r1

b°
r2

719 (HB) series 70 (HX) series

5
Bearing variants When compared to bearing arrangements Contact angles
with open bearings and external seals, those Standard bearings are manufactured with
Based on the operating conditions in preci- with sealed bearings provide a number of the following contact angles:
sion applications, bearing requirements can advantages including:
vary. As a result, there are many variants of • a 15° contact angle, designation suffix
SKF-SNFA super-precision angular contact • extended bearing service life CB (1)
ball bearings in the 719 .. B (HB) and 70 .. B • reduced need for maintenance • a 25° contact angle, designation suffix
(HX) series to choose from. • reduced inventory ACB (3)
Standard bearings are manufactured with • reduced risk of lubricant contamination
an integral seal fitted on both sides and filled during mounting and operation Bearings with an 18° contact angle, des-
with premium grease. As there is no friction ignation suffix FB (2), are available on
generated at the seal lip, the attainable Sealed bearings are identified by the desig- request.
speed of a sealed bearing is equivalent to nation prefix S (suffix /S). With three contact angles to choose from,
a comparably sized open bearing. designers can optimize their application
based on axial load, speed and rigidity
requirements.

Standard bearings are manufactured with an Three contact angles accommodate axial load,
integral seal fitted on both sides. speed and rigidity requirements.

15° 18° 25°

Sealed variant

The bearings are available in an all-steel and The bearings are available, standard, with seals
hybrid variant. but are also available in two open variants.

Steel balls Ceramic balls Open variant Open variant for

direct oil lubrication

6
Ball materials Open bearings Single bearings and
Standard bearings are available with: The bearings are also available without seals
for grease or oil lubrication in the 719 .. B matched bearing sets A
• steel balls, no designation suffix (HB) and 70 .. B (HX) series. To facilitate dir­ SKF-SNFA bearings in the S719 .. B
• ceramic (bearing grade silicon nitride) ect oil lubrication, the outer ring of open (HB .. /S) and S70 .. B (HX .. /S) series are
balls, designation suffix HC (/NS) bearings can also be manufactured with an available, standard, as:
annular groove and two lubrication holes as
As ceramic balls are considerably lighter and well as two annular grooves to accommo- • single bearings
harder than steel balls, hybrid bearings can date O-rings. This bearing variant is identi- • single, universally matchable bearings
provide a higher degree of rigidity and run fied by the designation suffix L (GH). • matched bearing sets
considerably faster than comparably sized • sets of universally matchable bearings
all-steel bearings. The lower weight of the
ceramic balls reduces the centrifugal forces
within the bearing and generates less heat.
Lower centrifugal forces are particularly
important in machine tool applications
where there are frequent rapid starts and
stops. Less heat generated by the bearing
means less energy consumption and longer
bearing and grease service life.

7
Applications

In the highly contaminated environment of

a machine tool spindle, one of the primary
causes of premature bearing failure is the
ingress of solid contaminants and/or cutting
fluid into the bearing cavity. To eliminate this
problem, the SKF-SNFA ­assortment of
sealed super-precision ­angular contact ball
bearings in the S719 .. B (HB .. /S) and
S70 .. B (HX .. /S) series is an excellent solu-
tion. The ability of the bearings to provide a
high degree of rigidity and accommodate
high speeds with extremely low runout pro-
vides a variety of benefits for different
applications.

Applications Requirements Solution

• Electro-spindles • Efficient sealing against
• Metal cutting machines contaminants
• Woodworking machines • Low energy consumption
• Milling machines • Long service life
• Machining centres • Facilitated mounting
• Increased machine uptime
• High power density for
compact designs
• High positioning accuracy

SKF-SNFA sealed super-precision angular

contact ball bearings in the S719 .. B (HB .. /S)
and S70 .. B (HX .. /S) series

8
 A

9
Bearing selection

Bearing selection is paramount when deal- • A larger contact angle provides a higher
ing with applications that require a high degree of axial stiffness.
­degree of accuracy at high speeds. The • When increased system rigidity is re-
many variants of SKF-SNFA sealed super- quired, bearings in the 719 (HB) series
precision angular contact ball bearings are accommodate a larger shaft diameter for
well suited to accommodate the conditions a given outside diameter, compared to
dictated by these applications. bearings in the 70 (HX) series.
The main criteria when selecting bearings • Bearings mounted in a back-to-back
in the S719 .. B (HB .. /S) and S70 .. B ­arrangement provide the highest degree
(HX .. /S) series are: of rigidity.

• precision
• rigidity Speed
• speed High-speed applications require cool-run-
• load ning, low-friction bearings like super-preci-
sion angular contact ball bearings.
When selecting bearings in the S719 .. B
Precision (HB .. /S) and S70 .. B (HX .. /S) series, the
When dealing with rolling bearings, preci- following should be considered:
sion is described by tolerance classes for
running and dimensional accuracy. • Hybrid bearings can operate at higher
When selecting bearings in the S719 .. B speeds than comparably sized all-steel
(HB .. /S) and S70 .. B (HX .. /S) series, the bearings.
following should be considered: • As the contact angle increases, speed
­capability decreases.
• All bearing variants are manufactured,
standard, to P4A (better than ABEC 7)
­tolerance class. Load
• All bearing variants can be manufactured In high-speed precision applications, the
to the higher precision PA9A (better than load carrying capacity of a bearing is typic-
ABEC 9) tolerance class, on request. ally less important than in general engineer-
ing applications. Angular contact ball bear-
ings can accommodate radial and axial loads
Rigidity acting simultaneously. When these com-
In precision applications, the rigidity of the bined loads exist, the direction of the load
bearing arrangement is extremely import­ also plays an important role in the selection
ant, as the magnitude of elastic deformation process.
under load determines the productivity and When selecting bearings in the S719 .. B
accuracy of the equipment. Although bear- (HB .. /S) and S70 .. B (HX .. /S) series, the
ing stiffness contributes to system ­rigidity, following should be considered:
there are other influencing factors such as
the number and position of the bearings. • The greater the contact angle, the higher
When selecting bearings in the S719 .. B the axial load carrying capacity of the
(HB .. /S) and S70 .. B (HX .. /S) series, the bearing.
following should be considered: • The axial load carrying capacity of a
­bearing arrangement can be increased
• Ceramic (silicon nitride) balls provide a by adding bearings mounted in tandem.
higher degree of stiffness than steel balls.

10
Bearing arrangement design
B

Bearing arrangements using SKF-SNFA Single, universally matchable Matched bearing sets
bearings in the S719 .. B (HB .. /S) and bearings Bearings can be supplied as complete
S70 .. B (HX .. /S) series can be designed ­bearing sets consisting of two, three or four
­using single bearings or bearing sets. An Universally matchable bearings are specif­ bearings. The bearings are matched to each
­example of the ordering possibilities for a ically manufactured so that when mounted other during production so that when
three-bearing arrangement is provided in in random order, but immediately adjacent mounted immediately adjacent to each ­other,
table 1. to each other, a given preload and/or even in a specified order, a given preload and/or
load distribution is obtained without the use even load distribution is obtained without
of shims or similar devices. These bearings the use of shims or similar devices. The bore
Single bearings can be mounted in random order for any and outside diameters of these bearings are
desired bearing arrangement. matched to within a maximum of one-third
SKF-SNFA bearings in the S719 .. B Single, universally matchable bearings of the applicable permitted ­diameter toler-
(HB .. /S) and S70 .. B (HX .. /S) series are are identified by the designation suffix G (U). ance, resulting in an even better load distri-
available as single (stand-alone) bearings or bution when mounted, compared to single,
single, universally matchable bearings. universally matchable bearings.
When ordering single bearings, indicate the Bearing sets
number of individual bearings required.
SKF-SNFA bearings in the S719 .. B Sets of universally matchable
(HB .. /S) and S70 .. B (HX .. /S) series are bearings
Single bearings available as matched bearing sets or as sets
Single bearings are intended for arrange- of universally matchable bearings. When The bearings in these sets can be mounted
ments where only one bearing is used in ­ordering bearing sets, indicate the number in random order for any desired bearing ar-
each bearing position. of bearing sets required (the number of in- rangement. The bore and outside diameters
Although the widths of the bearing rings dividual bearings per set is specified in the of universally matchable bearings in a set
are made to very tight tolerances, these designation). are matched to within a maximum of one-
bearings are not suitable for mounting im- third of the applicable permitted diameter
mediately adjacent to each other. tolerance, resulting in an even better load
distribution when mounted, compared to
single, universally matchable bearings.
Like single, universally matchable bear-
ings, sets of universally matchable bearings
are identified by the designation suffix G (U),
but their positions in the designation differ
(† table 15, pages 32 and 33).

Table 1

Example of the ordering possibilities for a three-bearing arrangement

Design criteria What to order Bearing designation1) Order example

Bearing arrangement is not known Three single, universally matchable bearings S719 .. BG../P4A 3 x S71914 CBGA/P4A
(HB .. /S 7CE .. U..) (3 x HB70 /S 7CE1 UL)

Bearing arrangement is not known and A set of three universally matchable bearings S719 .. B/P4ATG.. 1 x S71914 CB/P4ATGA
improved load distribution is desirable (HB .. /S 7CE .. TU..) (1 x HB70 /S 7CE1 TUL)

Bearing arrangement is known Three bearings in a matched set S719 .. B/P4AT.. 1 x S71914 CB/P4ATBTA
(HB .. /S 7CE .. TD..) (1 x HB70 /S 7CE1 TDL)

1) For additional information about designations, refer to table 15 on pages 32 and 33.

11
Type of arrangement Face-to-face bearing
arrangement
Universally matchable bearings and
matched bearing sets can be arranged in In a face-to-face bearing arrangement, the
various combinations depending on the load lines converge toward the bearing axis.
stiffness, rigidity and load requirements of Axial loads acting in both directions can be
the application. The possible combinations accommodated, but only by one bearing or
are shown in fig. 1, including the designa- bearing set in one direction each. Face-to-
tion suffixes applicable to matched bearing face arrangements can accommodate small
sets. amounts of deflection.

Back-to-back bearing Tandem bearing arrangement

arrangement In a tandem bearing arrangement, the load
lines are parallel so that radial and axial
In a back-to-back bearing arrangement, the loads are shared equally by the bearings in
load lines diverge toward the bearing axis. the set. The bearing set can only accommo-
Axial loads acting in both directions can be date axial loads acting in one direction. If
accommodated, but only by one bearing or ­axial loads act in the opposite direction, or if
bearing set in one direction each. Bearings combined loads are present, additional
mounted back-to-back provide a relatively bearing(s) adjusted against the tandem
rigid bearing arrangement that can also ­arrangement should be added.
­accommodate tilting moments.

12
 Fig. 1

Bearing sets with 2 bearings

Back-to-back arrangement Face-to-face arrangement Tandem arrangement

Designation suffix DB (DD) Designation suffix DF (FF) Designation suffix DT (T)

Bearing sets with 3 bearings

Back-to-back and tandem arrangement Face-to-face and tandem arrangement Tandem arrangement
Designation suffix TBT (TD) Designation suffix TFT (TF) Designation suffix TT (3T)

Bearing sets with 4 bearings

Tandem back-to-back arrangement Tandem face-to-face arrangement

Designation suffix QBC (TDT) Designation suffix QFC (TFT)

Back-to-back and tandem arrangement Face-to-face and tandem arrangement Tandem arrangement
Designation suffix QBT (3TD) Designation suffix QFT (3TF) Designation suffix QT (4T)

13
Application examples In high-speed machine tool applications, For any precision application, there is an
the spindle is often driven directly by a optimal arrangement to provide the best
Sealed super-precision angular contact ball ­motor. The spindle is then referred to as a possible combination of rigidity, load carry-
bearings are common in, but not limited to, motorized spindle or electro-spindle. As ing capacity, heat generation and bearing
machine tool applications. Depending on the there are only very light radial loads at the service life.
type of machine tool and its intended pur- non-tool end of this type of spindle, (com-
pose, spindles may have different require- pared with a belt-driven spindle), sets of
ments regarding bearing arrangements. ­super-precision angular contact ball bear-
ings are frequently used.

Electro-spindle in an internal grinding machine

In an internal grinding machine, where speeds are high and a high degree of rigidity is required, two pairs of sealed super-precision angular contact ball bear-
ings mounted back-to-back, e.g. S7014 CB/P4ADT (HX70 /S 7CE1 T) and S71910 CB/P4ADT (HB50 /S 7CE1 T), and preloaded with springs at the non-tool
end of the spindle, are suitable.

Electro-spindle in a high-speed milling machine

In the contaminated environment of a high-speed milling machine, where a high degree of rigidity is required and radial space is limited, two sets of matched
back-to-back sealed hybrid super-precision angular contact ball bearings, e.g. S7014 ACB/HCP4ADBB (HX70 /S/NS 7CE3 DDM) and S7012 ACB/HCP4ADBB
(HX60 /S/NS 7CE3 DDM), each incorporating a set of precision-matched spacer rings, can be used.

14
Electro-spindle in a high-speed metal cutting machine
For oil lubricated metal cutting spindles, where speeds are exceptionally high and loads are light, a back-to-back arrangement of open super-precision angular
contact ball bearings, e.g. 7020 ACB/P4ADTL (HX100 /GH 7CE3 T) and 7016 ACB/P4AL (HX80 /GH 7CE3), incorporating a set of precision-matched spacer
rings at the tool end, can be used.

Milling head spindle

For a milling head spindle, where speeds are high and a high degree of rigidity is required, a set of three universally matchable sealed hybrid super-precision
­angular contact ball bearings, e.g. S71914 ACBGA/HCP4A (HB70 /S/NS 7CE3 UL), can be used.

15
Lubrication and maintenance

Heat resulting from friction is a constant Sealed bearings Grease lubrication for
threat to production equipment. One way to
reduce heat and the wear associated with SKF-SNFA sealed bearings in the S719 .. B open bearings
friction, particularly in bearings, is to be sure (HB .. /S) and S70 .. B (HX .. /S) series are In most applications with open bearings in
that the correct quantity of the appropriate relubrication-free under normal operating the 719 .. B (HB) and 70 .. B (HX) series,
lubricant reaches all moving parts. conditions. They are filled with a high-grade, grease with a mineral base oil and lithium
For an adequate lubricant film to be low viscosity grease as standard. The grease thickener is suitable. These greases adhere
formed between the balls and raceways of is characterized by: well to the bearing surfaces and are suitable
super-precision angular contact ball bear- for operating temperatures ranging from
ings, only a very small amount of lubricant is • high-speed capability (speed factor A up –30 to +100 °C. For bearing arrangements
required. With grease lubrication, the hydro- to 1 600 000 mm/min) that operate at very high speeds and tem-
dynamic friction losses are small and oper- • excellent ageing resistance peratures, and where long service life is re-
ating temperatures can be kept to a min- • very good rust inhibiting properties quired, the use of grease based on a syn-
imum. However, where speeds are thetic oil, e.g. the diester oil based grease
constantly very high (generally, speed factor The technical specifications of the grease SKF LGLT 2, has been proven effective.
A > 1 800 000 mm/min), the bearings are provided in table 1. The quantity of
should be lubricated with oil, as the service grease fills approximately 15% of the free
life of grease is too short under these condi- space in the bearing.
tions and oil provides the added benefit of
cooling.
Table 2

Reference grease quantity for initial grease fill estimation

Bearing Reference grease quantity1)

Bore diameter Size for open bearings in the series
719 .. B (HB) 70 .. B (HX)
d Gref

mm – cm3

30 06 0,7 1,4
35 07 1,0 1,8
Table 1 40 08 1,4 2,2
45 09 1,8 2,9
Technical specifications of the grease in
sealed bearings 50 10 1,9 3,1
55 11 2,6 4,7
Properties Grease 60 12 2,8 5,0
specification 65 13 3,0 5,5

70 14 4,5 7,3
Thickener Special lithium 75 15 4,8 7,7
soap 80 16 5,3 10,5
85 17 6,5 11,0
Base oil type Ester/PAO
90 18 7,4 14,1
NLGI consistency class 2 95 19 7,5 14,7
100 20 10,0 15,3
Temperature range 110 22 11,4 22,3
[°C] –40 to +120
[°F] –40 to +250 120 24 14,0 23,7
Kinematic viscosity
[mm2/s]
at 40 °C 25
at 100 °C 6
1) Refers to a 30% filling grade.

16
Initial grease fill Running-in of sealed perature rise can be considerable. The rela-
In high-speed applications, less than 30% of
the free space in the bearings should be and open, grease tively high frictional moment is due to the
churning of the grease and it takes time for
filled with grease. The initial grease fill lubricated bearings the excess grease to work its way out of the
­depends on the bearing series and size as contact zone. For open bearings, this time
well as the speed factor, which is A grease lubricated super-precision bearing period can be minimized by applying a small
will initially run with a relatively high fric- quantity of grease distributed evenly on B
A = n dm tional moment. If the bearing is run at high both sides of the bearing during the assem-
speed without a running-in period, the tem- bly stage. Spacers between two adjacent
where
A = speed factor [mm/min] Diagram 1
n = rotational speed [r/min] Factor K for initial grease fill estimation
dm = bearing mean diameter Factor K
= 0,5 (d + D) [mm] 1,1
1,0
The initial grease fill for open bearings can
0,9
be estimated by
0,8
0,7
G = K Gref
0,6
where 0,5
G = initial grease fill [cm3] 0,4
K = a calculation factor dependent on the 0,3
speed factor A († diagram 1) 0,2
Gref = reference grease quantity 0,1
(† table 2) [cm3]
0
0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6
Speed factor A [106 mm/min]

Diagram 2

Graphic representation of a running-in procedure

Temperature [°C] Speed [r/min]

Absolute temperature limit

60

Operating
speed of the
10–15 min. for
system
stabilized temperature

20 0
† Stage 1 † Stage 2 † Stage 3 † Stage 4 † Stage 5 Time [h]

Operating temperature
Speed

17
bearings are also beneficial († Adjusting The short running-in procedure reduces Oil lubrication for
preload with spacer rings, page 24).
The time required to stabilize the operat-
the number of stages. Although each stage
may have to be repeated several times, each open bearings
ing temperature depends on a number of cycle is just a few minutes long, and the total Oil lubrication is recommended for open
factors – the type of grease, the initial time for this running-in process is substan- bearings in the 719 .. B (HB) and
grease fill, how the grease is applied to the tially shorter than the standard procedure. 70 .. B (HX) series in applications where
bearings, and the running-in procedure The main steps of the short running-in very high speeds (generally, speed factor
(† diagram 2 on page 17). procedure can be summarized as follows: A > 1 800 000 mm/min) preclude the
Super-precision bearings can typically use of grease lubricated bearings.
operate with minimal lubricant quantity 1 Select a starting speed approximately 20
when properly run-in, enabling the lowest to 25% of the attainable speed and choose
frictional moment and temperature to be a relatively large speed increment Oil-air lubrication method
achieved. The grease that collects at the interval. In some precision applications, the very high
sides of the bearing will act as a reservoir 2 Decide on an absolute temperature limit, operational speeds and requisite low oper-
and the oil can bleed into the raceways to usually 60 to 65 °C. It is advisable to set ating temperatures generally require an oil-
provide efficient lubrication for a long time. the equipment with limit switches that will air lubrication system. With the oil-air
Running-in can be done in several ways. stop the equipment if the temperature method, also called the oil-spot method, ac-
Wherever possible and regardless of the rise exceeds the set limit. curately metered quantities of oil are direct-
procedure chosen, running-in should in- 3 Start operation at the chosen initial ed at each individual bearing by compressed
volve operating the bearing in both a clock- speed. air. For bearings used in sets, each bearing
wise and anticlockwise direction. 4 Monitor the temperature by taking meas- is supplied by a separate oil injector. Most
The standard running-in procedure can urements at the bearing outer ring pos- designs include special spacers that incorp­
be summarized as follows: ition until the temperature reaches the orate the oil nozzles.
limit. Care should be taken as the tem- Guidelines for the quantity of oil to be
1 Select a low starting speed and a rela- perature increase may be very rapid. supplied to each bearing for very high speed
tively small speed increment interval. 5 Stop operation and let the outer ring of operation can be obtained from
2 Decide on an absolute temperature limit, the bearing cool down by 5 to 10 °C.
usually 60 to 65 °C. It is advisable to set 6 Start operation at the same speed a Q = 1,3 dm
the equipment with limit switches that will ­second time and monitor the temperature
stop the equipment if the temperature until the limit is reached again. where
rise exceeds the set limit. 7 Repeat steps 5 and 6 until the tempera- Q = oil flow rate [mm3/h]
3 Start operation at the chosen initial ture stabilizes below the limit. When the dm = bearing mean diameter
speed. temperature peak is lower than the alarm = 0,5 (d + D) [mm]
4 Monitor the temperature by taking meas- limit, the bearing is run-in at that particu-
urements at the bearing outer ring pos- lar speed. The calculated oil flow rate should be veri-
ition, avoiding peaks, and wait for it to 8 Increase the speed by one interval and fied during operation and adjusted, depend-
stabilize. If the temperature reaches the repeat steps 4 to 7. ing on the resulting temperatures.
limit, stop operation and allow the bear- 9 Repeat the running-in process until the
ing to cool. Start again at the same speed bearing is running at one speed interval
and wait for the temperature to stabilize. higher than the operating speed of the
5 Increase the speed by one interval and system. This results in a lower tempera-
repeat step 4. ture rise during normal operation. The
6 Continue increasing the speed in inter- bearing is now properly run-in.
vals, allowing the temperature to stabilize
below the limit at each stage. Proceed
­until this is achieved for one speed inter- Fig. 1
val greater than the operating speed of
the system. This results in a lower tem- Mixing valve
perature rise during normal operation.
The bearing is now properly run-in.

The standard running-in procedure is time- 0,5 to 10 m Helical coil

consuming and can take as long as 8 to 10
hours.
Oil + air line

Nozzle

18
 Oil is supplied to the feed lines at given
intervals by a metering unit. The oil coats
the inside surface of the feed lines and
“creeps” toward the nozzles († fig. 1),
where it is delivered to the bearings. The oil
nozzles should be positioned correctly
(† table 3) to make sure that the oil is intro­ B
duced into the contact area between the
balls and raceways and to avoid interference
with the cage.
High quality lubricating oils without
EP additives are generally recommended
for super-precision angular contact ball
bearings. Oils with a viscosity of 40 to
100 mm2/s at 40 °C are typically used.
A ­filter that prevents particles > 5 μm
from reaching the bearings should also
be incorporated.

Open bearings for direct oil Table 3

lubrication Oil nozzle position for oil-air lubrication

When a minimal amount of lubricant is to

be supplied directly and safely through the
­outer ring, open bearings with an annular
groove and two lubrication holes in the
­outer ring are recommended († fig. 2).
To prevent oil from leaking between the
bearing outside diameter and the housing
bore, the cylindrical surface of the outer d dn
ring has two additional annular grooves
to accommodate O-rings.
This bearing variant is identified by the Bearing Oil nozzle position
designation suffix L (GH) and is available for Bore diameter Size for open bearings in the series
719 .. B (HB) 70 .. B (HX)
bearings with a bore diameter d ≥ 40 mm. d dn

mm – mm

30 06 36,6 40
35 07 43 46,1
40 08 49,1 51,6
45 09 54,2 57,2

50 10 58,7 61,8
55 11 64,8 69,2
60 12 69,8 74,2
Fig. 2 65 13 74,8 79

70 14 81,9 86,1
75 15 86,9 91,1
80 16 91,7 98
85 17 99,2 103

90 18 103,9 110
95 19 109 115
100 20 116,1 120
110 22 125,7 134,6

120 24 138,2 144,7

19
Bearing data – general

Boundary dimensions Chamfer dimensions Tolerances

The boundary dimensions of SKF-SNFA Minimum values for the chamfer dimensions SKF-SNFA bearings in the S719 .. B
­super-precision angular contact ball bear- in the radial direction (r1, r3) and the axial (HB .. /S) and S70 .. B (HX .. /S) series are
ings are in accordance with ISO 15:1998: direction (r2, r4) are provided in the product manufactured, standard, to P4A tolerance
tables. The values for the chamfers on the class. On request, bearings can be supplied
• Boundary dimensions of bearings in the inner ring and thrust side of the outer ring to the higher precision PA9A tolerance class.
S719 .. B (HB .. /S) series are in accord- are in accordance with ISO 15:1998. The The tolerance values are listed as follows:
ance with ISO Dimension Series 19. values for the non-thrust side of the outer
• Boundary dimensions of bearings in the ring are smaller than those on the thrust • P4A (better than ABEC 7) tolerance class
S70 .. B (HX .. /S) series are in accordance side. in table 1
with ISO Dimension Series 10. The appropriate maximum chamfer ­limits • PA9A (better than ABEC 9) tolerance class
are in accordance with ISO 582:1995. in table 2

Table 1

Class P4A tolerances

Inner ring
d Δdmp Δds Vdp Vdmp ΔBs ΔB1s VBs Kia Sd Sia
over incl. high low high low max max high low high low max max max max

mm µm µm µm µm µm µm µm µm µm µm

18 30 0 –5 0 –5 1,5 1 0 –120 0 –250 1,5 2,5 1,5 2,5

30 50 0 –6 0 –6 1,5 1 0 –120 0 –250 1,5 2,5 1,5 2,5
50 80 0 –7 0 –7 2 1,5 0 –150 0 –250 1,5 2,5 1,5 2,5
80 120 0 –8 0 –8 2,5 1,5 0 –200 0 –380 2,5 2,5 2,5 2,5

Outer ring
D ΔDmp ΔDs VDp VDmp ΔCs, ΔC1s VCs Kea SD Sea
over incl. high low high low max max max max max max

mm µm µm µm µm µm µm µm µm

30 50 0 –6 0 –6 2 1,5 Values are identical to those for 1,5 2,5 1,5 2,5
50 80 0 –7 0 –7 2 1,5 the inner ring of the same bearing 1,5 4 1,5 4
80 120 0 –8 0 –8 2,5 1,5 (ΔBs, ΔB1s) 2,5 5 2,5 5
120 150 0 –9 0 –9 4 1,5 2,5 5 2,5 5
150 180 0 –10 0 –10 6 3 4 6 4 6

20
Bearing preload To meet the varying requirements Bearing sets consisting of three or four
r­ egarding rotational speed and rigidity, SKF- bearings have a heavier preload than sets
Preload in sets of universally SNFA bearings in the S719 .. B (HB .. /S) with two bearings. The preload for these
matchable bearings and and S70 .. B (HX .. /S) series are produced to bearing sets is obtained by multiplying the
matched bearing sets prior to different preload classes: values listed in table 3 on page 22 by a
mounting ­factor of:
• class A (L), light preload
A single super-precision angular contact ball • class B (M), moderate preload • 1,35 for TBT (TD) and TFT (TF)
bearing does not have any preload. Preload • class C (F), heavy preload arrangements
can only be obtained when one bearing is • 1,6 for QBT (3TD) and QFT (3TF)
placed against another to provide location in The preload level depends on the bearing arrangements
the opposite direction. series, the contact angle and the size of the • 2 for QBC (TDT) and QFC (TFT) C
Universally matchable bearings and bearing, and applies to bearing sets with arrangements
matched bearing sets are manufactured so two bearings arranged back-to-back or
that when the bearings are placed against face-to-face as listed in table 3 on page 22.
each other, prior to mounting, a certain
preload will result.

Table 2

Class PA9A tolerances

Inner ring
d Δdmp Δds Vdp Vdmp ΔBs ΔB1s VBs Kia Sd Sia
over incl. high low high low max max high low high low max max max max

mm µm µm µm µm µm µm µm µm µm µm

18 30 0 –2,5 0 –2,5 1,5 1 0 –120 0 –250 1,5 2,5 1,5 2,5

30 50 0 –2,5 0 –2,5 1,5 1 0 –120 0 –250 1,5 2,5 1,5 2,5
50 80 0 –4 0 –4 2 1,5 0 –150 0 –250 1,5 2,5 1,5 2,5
80 120 0 –5 0 –5 2,5 1,5 0 –200 0 –380 2,5 2,5 2,5 2,5

Outer ring
D ΔDmp ΔDs VDp VDmp ΔCs, ΔC1s VCs Kea SD Sea
over incl. high low high low max max max max max max

mm µm µm µm µm µm µm µm µm

30 50 0 –4 0 –4 2 1,5 Values are identical to those for the 1,5 2,5 1,5 2,5
50 80 0 –4 0 –4 2 1,5 inner ring of the same bearing (ΔBs, 1,5 4 1,5 4
80 120 0 –5 0 –5 2,5 1,5 ΔB1s) 2,5 5 2,5 5
120 150 0 –5 0 –5 2,5 1,5 2,5 5 2,5 5
150 180 0 –7 0 –7 4 3 2,5 5 2,5 5

21
Preload in mounted bearing During operation, an increase in preload where
sets is also caused by: Gm = preload in the mounted bearing set
[N]
Sets of universally matchable bearings and • the rotational speed of the shaft for GA,B,C = built-in preload in the bearing set,
matched bearing sets have a heavier ­constant position arrangements prior to mounting († table 3) [N]
preload when mounted compared to the • temperature gradients between the inner f = a bearing factor dependent on the
built-in preload, predetermined during ring, outer ring and balls bearing series and size († table 4)
manufacture. The increase in preload de- • different coefficient of thermal expansion f1 = a correction factor dependent on the
pends mainly on the actual tolerances for for the shaft and housing materials contact angle († table 5)
the bearing seats on the shaft and in the ­compared to the bearing steel f2 = a correction factor dependent on the
housing bore. An increase in preload can preload class († table 5)
also be caused by deviations from the geo- If the bearings are mounted with zero fHC = a correction factor for hybrid
metrical form of associated components ­interference on a steel shaft and in a thick- bearings († table 5)
such as cylindricity, perpendicularity or walled steel or cast iron housing, preload
­concentricity of the bearing seats. can be determined with sufficient accuracy Considerably tighter fits may be necessary,
from for example for very high speed spindles,
where centrifugal forces can loosen the
Gm = f f1 f2 fHC GA,B,C ­inner ring from its seat on the shaft. These
bearing arrangements must be carefully
evaluated.

Table 3

Axial preload of universally matchable bearings and matched bearing pairs, prior to mounting, arranged back-to-back or face-to-face

Bearing Axial preload

Bore Size of bearings in the series1)
diameter S719 CB (HB /S CE1) S719 ACB (HB /S CE3) S70 CB (HX /S CE1) S70 ACB (HX /S CE3)
S719 CB/HC (HB /S/NS CE1) S719 ACB/HC (HB /S/NS CE3) S70 CB /HC (HX /S/NS CE1) S70 ACB/HC (HX /S/NS CE3)
for preload class for preload class for preload class for preload class
d A B C A B C A B C A B C

mm – N

30 06 16 32 96 27 54 160 21 42 125 36 72 215

35 07 17 34 100 29 58 175 23 46 140 38 76 230
40 08 18 36 110 31 62 185 24 48 145 41 82 245
45 09 24 48 145 41 82 245 31 62 185 54 110 330

50 10 26 52 155 43 86 260 33 66 200 56 110 330

55 11 33 66 200 55 110 330 46 92 275 78 155 470
60 12 34 68 205 57 115 340 48 96 290 80 160 480
65 13 35 70 210 60 120 360 49 98 295 85 170 510

70 14 45 90 270 75 150 450 64 130 390 110 220 660

75 15 46 92 275 80 160 480 65 130 390 115 230 690
80 16 52 105 310 87 175 520 78 155 470 150 300 900
85 17 54 110 325 93 185 560 80 160 480 150 300 900

90 18 59 120 355 100 200 600 92 185 550 160 320 960
95 19 60 120 360 105 210 630 94 190 570 165 330 990
100 20 72 145 430 125 250 750 96 190 570 165 330 990
110 22 86 170 515 145 290 870 125 250 750 210 420 1 260

120 24 90 180 540 155 310 930 130 260 780 220 440 1 320

1) Data is also applicable to open bearings. Data for bearings with an 18° contact angle is available on request.

22
Preload with constant force
In precision, high-speed applications, a
­constant and uniform preload is important.
To maintain the proper preload, calibrated
­linear springs can be used between one
bearing outer ring and its housing shoulder
(† fig. 1). With springs, the kinematic
­behaviour of the bearing will not influence
preload under normal operating conditions.
Note, however, that a spring-loaded bearing
arrangement has a lower degree of rigidity Table 4
than an arrangement using axial displace- Bearing factor f for calculating the preload in mounted bearing sets C
ment to set the preload.
Bearing Bearing factor f
Bore diameter Size for all-steel bearings in the series1)

Preload by axial displacement d S719 .. B (HB .. /S) S70 .. B (HX .. /S)

Rigidity and precise axial guidance are crit­ mm – –
ical parameters in bearing arrangements,
especially when alternating axial forces
30 06 1,07 1,03
­occur. In these cases, the preload in the 35 07 1,06 1,04
bearings is usually obtained by adjusting 40 08 1,06 1,04
the bearing rings relative to each other in 45 09 1,08 1,05
the axial direction. This preload method 50 10 1,09 1,06
­offers significant benefits in terms of system 55 11 1,09 1,06
rigidity. However, depending on the bearing 60 12 1,11 1,06
65 13 1,13 1,07
series, contact angle and ball material,
preload increases considerably with rota- 70 14 1,1 1,07
75 15 1,11 1,08
tional speed. 80 16 1,13 1,07
Universally matchable bearings and 85 17 1,11 1,08
matched bearing sets are manufactured so
90 18 1,12 1,07
that when mounted properly, they will attain 95 19 1,13 1,07
their predetermined axial displacement and 100 20 1,11 1,08
consequently the proper preload. With sin- 110 22 1,14 1,07
gle bearings, precision-matched spacer 120 24 1,13 1,08
rings must be used.

1) Data is also applicable to open bearings. For hybrid bearings, f = 1.

Table 5

Correction factors for calculating the preload in mounted bearing sets

Bearing series1) Correction factors

f1 f2 fHC
for preload class
Fig. 1 A B C

S719 CB (HB .. /S CE1) 1 1 1,02 1,07 1

S719 ACB (HB .. /S CE3) 0,99 1 1,02 1,07 1
S719 CB/HC (HB .. /S/NS CE1) 1 1 1,03 1,08 1,01
S719 ACB/HC (HB .. /S/NS CE3) 0,99 1 1,02 1,08 1,01

S70 CB (HX .. /S CE1) 1 1 1,02 1,05 1

S70 ACB (HX .. /S CE3) 0,99 1 1,01 1,04 1
S70 CB/HC (HX .. /S/NS CE1) 1 1 1,02 1,05 1,01
S70 ACB/HC (HX .. /S/NS CE3) 0,99 1 1,02 1,05 1,01

1) Data is also applicable to open bearings. Data for bearings with an 18° contact angle is available on request.

23
Adjusting preload with spacer • create a sufficiently large grease reservoir ring side faces must be ground and what
rings between two bearings ­effect it will have. Guideline values for the
• create a space for oil-air lubrication requis­ite overall width reduction of the
By placing precision-matched spacer rings nozzles spacer rings are listed in table 7.
between two bearings, it is possible to To achieve maximum bearing perform-
­increase or decrease preload. Precision- It is possible to adjust preload in a bearing ance, the spacer rings must not deform
matched spacer rings can also be used to set, by grinding the side face of the inner or ­under load. They should be made of high-
outer spacer ring. Table 6 provides informa- grade steel that can be hardened to between
• increase system rigidity tion about which of the equal-width spacer 45 and 60 HRC. Particular importance must
be given to the plane parallelism of the side
Table 6 face surfaces, where the permissible shape
Guidelines for spacer ring modification deviation must not exceed 1 to 2 μm.

Preload change of a bearing set Width reduction Requisite spacer ring

Value between bearings arranged
back-to-back face-to-face

Increasing the preload

from A to B a inner outer
from B to C b inner outer
from A to C a+b inner outer

Decreasing the preload

from B to A a outer inner
from C to B b outer inner
from C to A a+b outer inner

Table 7

Guideline values for spacer ring width reduction

a, b a, b

a, b a, b
Increasing the preload Decreasing the preload Increasing the preload Decreasing the preload
(back-to-back arrangement) (back-to-back arrangement) (face-to-face arrangement) (face-to-face arrangement)

Bearing Requisite spacer ring width reduction

Bore Size for bearings in the series1)
diameter S719 CB (HB /S CE1) S719 ACB (HB /S CE3) S70 CB (HX /S CE1) S70 ACB (HX /S CE3)
d a b a b a b a b

mm – μm

30 06 3 8 2 6 3 10 2 7
35 07 3 8 2 6 3 10 2 7
40 08 3 8 2 6 3 10 2 7
45 09 3 9 2 6 4 10 3 7
50 10 3 9 2 6 4 11 3 7

55 11 4 11 2 7 4 12 3 9
60 12 4 11 2 7 4 13 3 9
65 13 4 11 2 7 5 13 3 9
70 14 4 12 3 8 5 15 3 10
75 15 4 12 3 8 5 15 3 10

80 16 4 12 3 8 6 16 4 12
85 17 4 12 3 8 6 16 4 12
90 18 5 13 3 9 7 18 4 13
95 19 5 13 3 9 7 18 4 13
100 20 5 14 3 9 7 18 4 13

110 22 5 16 4 10 7 19 4 13
120 24 5 16 4 10 7 19 4 13
1) Data is also applicable to open bearings. Data for bearings with an 18° contact angle is available on request.

24
Effect of rotational speed on Bearing axial stiffness Bearing sets comprising three or four
preload bearings can provide a higher degree of
Axial stiffness depends on the deformation ­axial stiffness than sets with two bearings.
Using strain gauges, SKF has determined of the bearing under load and can be ex- The axial stiffness for these sets can be cal-
that there is a marked increase in preload at pressed as the ratio of the load to bearing culated by multiplying the values listed in
very high speeds. This is mainly attributable resilience. However, since the resilience of table 8 by a factor dependent on the bear-
to the heavy centrifugal forces on the balls rolling bearings does not depend linearly on ing arrangement and preload class of the
causing them to change their position within the load, axial stiffness is also load-depend- bearings:
the bearing. When compared to an all-steel ent. Exact values of axial stiffness, for SKF-
bearing, a hybrid bearing can attain much SNFA bearings in the S719 .. B (HB .. /S) • 1,45 for TBT (TD) and TFT (TF)
higher rotational speeds without ­significantly and S70 .. B (HX .. /S) series, for a given arrangements
increasing preload. This is due to the ­lower preload can be calculated using advanced • 1,8 for QBT (3TD) and QFT (3TF) C
mass of the balls. computer methods, but guideline values are arrangements
listed in table 8. These values apply to • 2 for QBC (TDT) and QFC (TFT)
mounted bearing sets under static condi- arrangements
tions with two all-steel bearings arranged
back-to-back or face-to-face and subjected For hybrid bearings, the axial stiffness can
to moderate loads. be calculated by multiplying the values listed
in table 8 by a factor of 1,11 regardless of
the arrangement or preload class.

Table 8

Static axial stiffness for bearing pairs arranged back-to-back or face-to-face

Bearing Static axial stiffness

Bore Size of all-steel bearings in the series1)
diameter S719 CB (HB /S CE1) S719 ACB (HB /S CE3) S70 CB (HX /S CE1) S70 ACB (HX /S CE3)
for preload class for preload class for preload class for preload class
d A B C A B C A B C A B C

mm – N/μm

30 06 16 20 33 68 87 130 22 29 46 100 126 190

35 07 17 22 34 74 95 142 25 33 52 106 136 204
40 08 19 24 39 84 107 158 28 36 57 121 158 233
45 09 22 29 47 98 126 190 31 40 64 138 183 280

50 10 24 32 50 102 132 202 33 43 69 147 183 273

55 11 24 32 53 106 136 206 38 50 80 170 215 331
60 12 26 34 54 112 146 214 41 54 86 178 225 338
65 13 27 36 58 122 158 238 41 54 85 185 239 359

70 14 31 39 63 132 167 251 47 63 99 212 268 405

75 15 32 42 68 148 190 287 50 65 104 235 299 451
80 16 33 44 68 140 184 272 52 68 109 278 353 529
85 17 35 47 74 158 201 308 54 71 112 278 353 533

90 18 34 46 72 152 192 294 54 71 112 246 317 480

95 19 36 46 74 164 208 317 56 74 117 258 330 497
100 20 45 60 95 205 266 403 58 76 120 262 337 510
110 22 46 59 96 201 257 392 71 93 147 309 396 597

120 24 49 65 104 225 290 437 75 98 156 333 427 641

1) Data is also applicable to open bearings. Data for bearings with an 18° contact angle is available on request.

25
Fitting and clamping of The tightening torque Mt, for precision The tightening torque for end cap bolts is

bearing rings lock nuts or end cap bolts, must be sufficient

to prevent relative movement of adjacent K Pa

Super-precision angular contact ball bear- components, maintain the position of the Mt = –––––
ings are typically located axially on shafts or bearings without deformation, and minimize Nb
in housings with either precision lock nuts material fatigue.
(† fig. 2) or end caps. These components K [Fs + (NcpFc) + GA,B,C]
require high geometrical precision and good Mt = –––––––––––––––––––
mechanical strength to provide reliable Calculating the tightening Nb
locking. torque Mt
where
It is difficult to accurately calculate the tight- Mt = tightening torque [Nmm]
ening torque Mt. The following formulas can Pa = axial clamping force [N]
be used as guidelines, but the results should Fs = minimum axial clamping force
be verified during operation. († table 9) [N]
Fig. 2 The axial clamping force for a precision Fc = axial fitting force († table 9) [N]
lock nut or the bolts in an end cap is GA,B,C = built-in bearing preload, prior to
mounting († table 3 on page 22)
Pa = Fs + (NcpFc) + GA,B,C [N]
Ncp = the number of preloaded bearings
The tightening torque for a precision lock Nb = the number of end cap bolts
nut is K = a calculation factor dependent on
the thread († table 10)
Mt = K Pa
= K [Fs + (NcpFc) + GA,B,C]

Table 9

Minimum axial clamping force and axial fitting force for precision lock nuts and end caps

Bearing Minimum axial clamping force Axial fitting force

Bore diameter Size for bearings in the series1) for bearings in the series1)
S719 .. B (HB .. /S) S70 .. B (HX .. /S) S719 .. B (HB .. /S) S70 .. B (HX .. /S)
d Fs Fc

mm – N N

30 06 1 900 2 500 300 550

35 07 2 600 3 300 440 750
40 08 3 100 4 100 500 750
45 09 3 800 4 500 480 750

50 10 3 100 5 000 380 650

55 11 4 100 6 000 430 800
60 12 4 500 6 500 400 750
65 13 4 800 7 000 370 700

70 14 6 500 8 500 500 800

75 15 6 500 9 000 480 750
80 16 7 000 11 000 650 1 200
85 17 9 000 11 000 900 1 400

90 18 9 500 16 000 850 1 700

95 19 10 000 14 000 850 1 500
100 20 12 000 15 000 1 000 1 400
110 22 13 000 20 000 900 1 800

120 24 16 000 22 000 1 200 1 900

1) Data is also applicable to open bearings.

26
Load carrying capacity Equivalent bearing
of bearing sets loads
The values listed in the product tables for When determining the equivalent bearing
the basic dynamic load rating C, the basic load for preloaded bearings, the preload
static load rating C0 and the fatigue load must be taken into account. Depending on
limit Pu apply to single bearings. For bearing the operating conditions, the requisite axial
sets, the values for single bearings should component of the bearing load Fa for a
be multiplied by a calculation factor accord- bearing pair arranged back-to-back or face-
ing to table 11. to-face can be approximated using the fol-
lowing equations.
C
For bearing pairs under radial load and
mounted with an interference fit

Table 10 Fa = Gm
Factor K for calculating the tightening
torque For bearing pairs under radial load and
preloaded by springs
Nominal Factor K
thread for
diameter1) precision end cap bolts Fa = GA,B,C
lock nuts

– – For bearing pairs under axial load and

mounted with an interference fit
M4 – 0,8
M5 – 1 Fa = Gm + 0,67 Ka for Ka ≤ 3 Gm
M6 – 1,2 Fa = Ka for Ka > 3 Gm
M8 – 1,6

M 10 1,4 2 For bearing pairs under axial load and

M 12 1,6 2,4 preloaded by springs
M 14 1,9 2,7
M 15 2 2,9
Fa = GA,B,C + Ka
M 16 2,1 3,1
M 17 2,2 –
M 20 2,6 – where
M 25 3,2 – Fa = axial component of the load [N]
M 30 3,9 – GA,B,C = built-in preload of the bearing pair,
M 35 4,5 – prior to mounting († table 3 on
M 40 5,1 – page 22) [N]
M 45 5,8 –
Gm = preload in the mounted bearing pair
M 50 6,4 – († Preload in mounted bearing
M 55 7 – sets, page 22) [N]
M 60 7,6 –
M 65 8,1 – Ka = external axial force acting on a
single bearing [N]
M 70 9 –
M 75 9,6 –
M 80 10 –
M 85 11 – Table 11

M 90 11 – Calculation factors for load carrying

M 95 12 – capacities of bearing sets
M 100 12 –
M 105 13 – Number of Calculation factor
bearings for
M 110 14 – C C0 Pu
M 120 15 –
M 130 16 –
M 140 17 – 2 1,62 2 2

M 150 18 – 3 2,16 3 3
M 160 19 –
4 2,64 4 4

1) Applicable for fine threads only

27
Equivalent dynamic bearing where Equivalent static bearing load
load P = equivalent dynamic load of the bearing For single bearings and bearings paired in
set [kN] tandem
For single bearings and bearings paired in Fr = radial component of the load acting on
tandem the bearing set [kN] P0 = 0,5 Fr + Y0Fa
Fa = axial component of the load acting on
P = Fr for Fa/Fr ≤ e the bearing set [kN] For bearing pairs, arranged back-to-back or
P = XFr + YFa for Fa/Fr > e face-to-face
The values for the calculation factors e, X, Y,
For bearing pairs, arranged back-to-back or Y1 and Y2 depend on the bearing contact P0 = Fr + Y0Fa
face-to-face ­angle and are listed in tables 12 and 13.
For bearings with a 15° contact angle, the where
P = Fr + Y1Fa for Fa/Fr ≤ e factors also depend on the relationship P0 = equivalent static load of the bearing set
P = XFr + Y2Fa for Fa/Fr > e f0Fa/C0 where f0 is the calculation factor [kN]
and C0 is the basic static load rating, both Fr = radial component of the load acting on
of which are listed in the product tables. the bearing set [kN]
Fa = axial component of the load acting on
the bearing set [kN]

If P0 < Fr , P0 = Fr should be used. The values

Table 12 for the calculation factor Y0 depend on the
Calculation factors for single bearings and bearings paired in tandem bearing contact angle and are listed in
tables 12 and 13.
f0Fa/C0 Calculation factors
e X Y Y0

For 15° contact angle

Attainable speeds
designation suffix CB (1)
The attainable speeds listed in the product
≤ 0,178 0,38 0,44 1,47 0,46 tables should be regarded as guideline
0,357 0,4 0,44 1,4 0,46
0,714 0,43 0,44 1,3 0,46 ­values. They are valid for single bearings
1,07 0,46 0,44 1,23 0,46 under light load (P ≤ 0,05 C) that are lightly
preloaded using springs. In addition, good
1,43 0,47 0,44 1,19 0,46
2,14 0,5 0,44 1,12 0,46 heat dissipation from the bearing arrange-
3,57 0,55 0,44 1,02 0,46 ment is a prerequisite.
≥ 5,35 0,56 0,44 1 0,46 The values provided for oil lubrication
For 25° contact angle ­apply to the oil-air lubrication method and
designation suffix ACB (3) should be reduced if other oil lubrication
– 0,68 0,41 0,87 0,38
Note: Data for bearings with an 18° contact angle is available on request.
methods are used. The values provided for
grease lubrication are maximum values that
can be attained with sealed bearings or
Table 13 open bearings with good lubricating grease
Calculation factors for bearing pairs arranged back-to-back or face-to-face that has a low consistency and low viscosity.
If single bearings are adjusted against
2 f0Fa/C0 Calculation factors each other with heavier preload or if bearing
e X Y1 Y2 Y0
sets are used, the attainable speeds listed in
the product tables should be reduced i.e. the
For 15° contact angle
designation suffix CB (1) values should be multiplied by a reduction
factor. Values for this reduction factor, which
≤ 0,178 0,38 0,72 1,65 2,39 0,92 depend on the bearing arrangement and
0,357 0,4 0,72 1,57 2,28 0,92
0,714 0,43 0,72 1,46 2,11 0,92 preload class, are listed in table 14.
1,07 0,46 0,72 1,38 2 0,92 If the rotational speed obtained is not suf-
ficient for the application, precision-matched
1,43 0,47 0,72 1,34 1,93 0,92
2,14 0,5 0,72 1,26 1,82 0,92 spacer rings in the bearing set can be used
3,57 0,55 0,72 1,14 1,66 0,92 to significantly increase the speed capability.
≥ 5,35 0,56 0,72 1,12 1,63 0,92 SKF-SNFA sealed bearings in the S719 .. B
For 25° contact angle (HB .. /S) and S70 .. B (HX .. /S) series are
designation suffix ACB (3) designed for high-speed operation i.e. for a
– 0,68 0,67 0,92 1,41 0,76
Note: Data for bearings with an 18° contact angle is available on request.
speed factor A up to 1 600 000 mm/min.

28
Cages Materials Heat treatment
SKF-SNFA bearings in the S719 .. B The rings and balls of SKF-SNFA all-steel All SKF-SNFA super-precision bearings
(HB .. /S) and S70 .. B (HX .. /S) series have a bearings in the S719 .. B (HB .. /S) and ­undergo a special heat treatment to achieve
one-piece outer ring shoulder-guided cage S70 .. B (HX .. /S) series are made from SKF a good balance between hardness and
made of fabric reinforced phenolic resin Grade 3 steel, in accordance with ISO ­dimensional stability. The hardness of the
(† fig. 3) that can withstand temperatures 683-17:1999. Balls of hybrid bearings are rings and rolling elements is optimized for
up to 120 °C. made of bearing grade silicon nitride Si3N4. wear-resistance.
The integral seals are made of an oil-and
wear-resistant acrylonitrile-butadiene rub-
Seals ber (NBR) and are reinforced with sheet
steel. The O-rings of open bearings that are C
The non-contact seals in SKF-SNFA used for direct oil lubrication are also made
S719 .. B (HB .. /S) and S70 .. B (HX .. /S) of acrylonitrile-butadiene rubber.
series bearings are made of acrylonitrile-
butadiene rubber (NBR) and are designed
for high-speed operation (speed factor A up
to 1 600 000 mm/min). The permissible op-
erating temperature range of the seals is
–25 to +100 °C and up to 120 °C for brief
periods.

Fig. 3 Table 14

Speed reduction factors for bearing sets

Number of Arrangement Designation suffix Speed reduction factor

bearings for preload class
A B C

2 Back-to-back DB (DD) 0,83 0,78 0,58

Face-to-face DF (FF) 0,8 0,74 0,54

3 Back-to-back and tandem TBT (TD) 0,72 0,66 0,4

Face-to-face and tandem TFT (TF) 0,64 0,56 0,3

4 Tandem back-to-back QBC (TDT) 0,67 0,64 0,48

Tandem face-to-face QFC (TFT) 0,64 0,6 0,41

29
Marking of bearings “V-shaped” marking Fig. 5

and bearing sets A “V-shaped” marking on the outside sur-

face of the outer rings of matched bearing
Each SKF-SNFA bearing in the S719 .. B sets indicates how the bearings should be
(HB .. /S) and S70 .. B (HX .. /S) series has mounted to obtain the proper preload in
various identifiers on the external surfaces the set. The marking also indicates how the
of the rings († fig. 4): bearing set should be mounted in relation Fa
to the axial load. The “V-shaped” marking
1 SKF trademark should point in the direction in which the
2 Complete designation of the bearing ­axial load will act on the inner ring (†
3 Country of manufacture fig. 5). In applications where there are axial
4 Date of manufacture, coded loads in both directions, the “V-shaped”
5 Deviation from the mean outside marking should point toward the greater of
­diameter, DDm [µm] the two loads.
6 Deviation from the mean bore diameter,
Ddm [µm]
7 Serial number (bearing sets only)
8 “V-shaped” marking (matched bearing
sets only)

The deviations from the mean outside and

bore diameters are marked at the point of
maximum wall thickness on their respective
rings.

Fig. 4

6
5

4 2

30
Packaging Fig. 6

SKF-SNFA super-precision bearings are

distributed in dual branded boxes († fig. 6).
The boxes are marked with both the SKF
and SNFA bearing designations. An instruc-
tion sheet, with information about mounting
bearing sets, is supplied in each box.

Designation system
C
The designations for SKF-SNFA bearings in
the 719 .. B (HB) and 70 .. B (HX) series are
provided in table 15 on pages 32 and 33
together with their definitions.

31
 Designation system for SKF-SNFA super-precision angular contact ball bearings in the 719 .. B (HB) and 70 .. B (HX) series

Single bearing:
S 719 12 ACB GA / HC P4A
S71912 ACBGA/HCP4A

Variant Contact Execution

Ball Tolerance Variant
prefix Series Size angle and preload Arrangement Preload
and design (single bearing) material class suffix

Matched bearing set:

70 06 CB / PA9A QBC B L
7006 CB/PA9AQBCBL

Variant (prefix)
– Open bearing (no designation prefix)
S Sealed bearing
V Bearing with NitroMax steel rings and bearing grade silicon nitride Si3N4 balls1)

Bearing series
719 In accordance with ISO Dimension Series 19
70 In accordance with ISO Dimension Series 10

Bearing size
6 (x5) 30 mm bore diameter
to
24 (x5) 120 mm bore diameter

Contact angle and internal design

CB 15° contact angle, high-speed B design
FB 18° contact angle, high-speed B design
ACB 25° contact angle, high-speed B design

Single bearing – execution and preload

– Single bearing (no designation suffix)
GA Single, universally matchable, for light preload
GB Single, universally matchable, for moderate preload
GC Single, universally matchable, for heavy preload

Cage
– Fabric reinforced phenolic resin, outer ring centred (no designation suffix)

Ball material
– Carbon chromium steel (no designation suffix)
HC Bearing grade silicon nitride Si3N4 (hybrid bearings)

Tolerance class
P4A Dimensional accuracy in accordance with ISO tolerance class 4, running accuracy better than ISO tolerance class 4
PA9A Dimensional and running accuracy better than ABMA tolerance class ABEC 9

Bearing set – arrangement

DB Two bearings arranged back-to-back <>
DF Two bearings arranged face-to-face ><
DT Two bearings arranged in tandem <<
DG Two bearings for universal matching
TBT Three bearings arranged back-to-back and tandem <>>
TFT Three bearings arranged face-to-face and tandem ><<
TT Three bearings arranged in tandem <<<
TG Three bearings for universal matching
QBC Four bearings arranged tandem back-to-back <<>>
QFC Four bearings arranged tandem face-to-face >><<
QBT Four bearings arranged back-to-back and tandem <>>>
QFT Four bearings arranged face-to-face and tandem ><<<
QT Four bearings arranged in tandem <<<<
QG Four bearings for universal matching

Bearing set – preload

A Light preload
B Moderate preload
C Heavy preload
G_ Special preload, expressed in daN e.g. G240

Additional open bearing variant

L Annular grooves, lubrication holes and O-rings in the outer ring for direct oil lubrication

1) For additional information, contact the SKF application engineering service.

32
 Table 15

SNFA designation system for super-precision angular contact ball bearings in the 719 .. B (HB) and 70 .. B (HX) series

Single bearing:
HB 60 /S /NS 7 CE 3 U L
HB60 /S/NS 7CE3 UL

Series and Ball Tolerance Contact

Size Variant Cage Arrangement Preload
design material class angle

Matched bearing set:

HX 30 /GH 9 CE 1 TDT M
HX30 /GH 9CE1 TDTM

Variant
– Open bearing (no designation suffix) C
/S Sealed bearing
/XN Bearing with NitroMax steel rings and bearing grade silicon nitride Si3N4 balls1)

Bearing series and internal design

HB In accordance with ISO Dimension Series 19, high-speed HB design
HX In accordance with ISO Dimension Series 10, high-speed HX design

Bearing size
30 30 mm bore diameter
to
120 120 mm bore diameter

Contact angle
1 15° contact angle
2 18° contact angle
3 25° contact angle

Single bearing – execution and preload

– Single bearing (no designation suffix)
UL Single, universally matchable, for light preload
UM Single, universally matchable, for moderate preload
UF Single, universally matchable, for heavy preload

Cage
CE Fabric reinforced phenolic resin, outer ring centred

Ball material
– Carbon chromium steel (no designation suffix)
/NS Bearing grade silicon nitride Si3N4 (hybrid bearings)

Tolerance class
7 Dimensional and running accuracy in accordance with ABMA tolerance class ABEC 7
9 Dimensional and running accuracy in accordance with ABMA tolerance class ABEC 9

Bearing set – arrangement

DD Two bearings arranged back-to-back <>
FF Two bearings arranged face-to-face ><
T Two bearings arranged in tandem <<
DU Two bearings for universal matching
TD Three bearings arranged back-to-back and tandem <>>
TF Three bearings arranged face-to-face and tandem ><<
3T Three bearings arranged in tandem <<<
TU Three bearings for universal matching
TDT Four bearings arranged tandem back-to-back <<>>
TFT Four bearings arranged tandem face-to-face >><<
3TD Four bearings arranged back-to-back and tandem <>>>
3TF Four bearings arranged face-to-face and tandem ><<<
4T Four bearings arranged in tandem <<<<
4U Four bearings for universal matching

Bearing set – preload

L Light preload (for symmetrical sets only)
M Moderate preload (for symmetrical sets only)
F Heavy preload (for symmetrical sets only)
..daN Special preload (for asymmetrical sets TD, TF, 3TD, 3TF and for special preload executions)1)

Additional open bearing variant

/GH Annular grooves, lubrication holes and O-rings in the outer ring for direct oil lubrication

33
Super-precision angular contact ball bearings
d 30 – 50 mm
B
r2 r4 C1
r1 r3 b
C3
r1 r1 C2
r2 r2

D D1 d d1

a Open variant for

Sealed variant Open variant ­direct oil lubrication

Principal dimensions Basic load ratings Fatigue Calculation Attainable speed Mass3) Designations of sealed bearings4)
dynamic1) static load limit factor when lubricating with SKF SNFA
grease oil-air2)
d D B C C0 Pu f0

mm kN kN – r/min kg –

30 47 9 4,88 3,15 0,134 9,5 40 000 60 000 0,050 S71906 CB/P4A HB30 /S 7CE1
47 9 4,88 3,15 0,134 9,5 48 000 75 000 0,047 S71906 CB/HCP4A HB30 /S/NS 7CE1
47 9 4,62 3 0,127 – 36 000 56 000 0,050 S71906 ACB/P4A HB30 /S 7CE3
47 9 4,62 3 0,127 – 43 000 67 000 0,047 S71906 ACB/HCP4A HB30 /S/NS 7CE3
55 13 6,5 4,15 0,176 9,4 36 000 56 000 0,13 S7006 CB/P4A HX30 /S 7CE1
55 13 6,5 4,15 0,176 9,4 43 000 67 000 0,13 S7006 CB/HCP4A HX30 /S/NS 7CE1
55 13 6,18 3,9 0,166 – 34 000 50 000 0,13 S7006 ACB/P4A HX30 /S 7CE3
55 13 6,18 3,9 0,166 – 40 000 60 000 0,13 S7006 ACB/HCP4A HX30 /S/NS 7CE3

35 55 10 5,2 3,65 0,156 9,7 34 000 53 000 0,081 S71907 CB/P4A HB35 /S 7CE1
55 10 5,2 3,65 0,156 9,7 40 000 63 000 0,077 S71907 CB/HCP4A HB35 /S/NS 7CE1
55 10 4,88 3,45 0,146 – 30 000 48 000 0,081 S71907 ACB/P4A HB35 /S 7CE3
55 10 4,88 3,45 0,146 – 36 000 56 000 0,077 S71907 ACB/HCP4A HB35 /S/NS 7CE3
62 14 6,89 4,8 0,204 9,6 32 000 48 000 0,17 S7007 CB/P4A HX35 /S 7CE1
62 14 6,89 4,8 0,204 9,6 38 000 60 000 0,16 S7007 CB/HCP4A HX35 /S/NS 7CE1
62 14 6,5 4,55 0,193 – 28 000 43 000 0,17 S7007 ACB/P4A HX35 /S 7CE3
62 14 6,5 4,55 0,193 – 34 000 53 000 0,16 S7007 ACB/HCP4A HX35 /S/NS 7CE3

40 62 12 5,4 4,15 0,176 9,8 30 000 45 000 0,12 S71908 CB/P4A HB40 /S 7CE1
62 12 5,4 4,15 0,176 9,8 36 000 56 000 0,12 S71908 CB/HCP4A HB40 /S/NS 7CE1
62 12 5,07 4 0,166 – 28 000 43 000 0,12 S71908 ACB/P4A HB40 /S 7CE3
62 12 5,07 4 0,166 – 32 000 50 000 0,12 S71908 ACB/HCP4A HB40 /S/NS 7CE3
68 15 7,41 5,6 0,236 9,8 28 000 43 000 0,21 S7008 CB/P4A HX40 /S 7CE1
68 15 7,41 5,6 0,236 9,8 34 000 53 000 0,20 S7008 CB/HCP4A HX40 /S/NS 7CE1
68 15 6,89 5,3 0,224 – 26 000 40 000 0,21 S7008 ACB/P4A HX40 /S 7CE3
68 15 6,89 5,3 0,224 – 32 000 48 000 0,20 S7008 ACB/HCP4A HX40 /S/NS 7CE3

45 68 12 7,41 5,7 0,245 9,7 28 000 43 000 0,14 S71909 CB/P4A HB45 /S 7CE1
68 12 7,41 5,7 0,245 9,7 32 000 50 000 0,13 S71909 CB/HCP4A HB45 /S/NS 7CE1
68 12 7,02 5,4 0,232 – 24 000 38 000 0,14 S71909 ACB/P4A HB45 /S 7CE3
68 12 7,02 5,4 0,232 – 30 000 45 000 0,13 S71909 ACB/HCP4A HB45 /S/NS 7CE3
75 16 9,56 7,2 0,305 9,6 26 000 40 000 0,26 S7009 CB/P4A HX45 /S 7CE1
75 16 9,56 7,2 0,305 9,6 30 000 48 000 0,25 S7009 CB/HCP4A HX45 /S/NS 7CE1
75 16 9,04 6,8 0,285 – 24 000 36 000 0,26 S7009 ACB/P4A HX45 /S 7CE3
75 16 9,04 6,8 0,285 – 28 000 43 000 0,25 S7009 ACB/HCP4A HX45 /S/NS 7CE3

50 72 12 7,61 6,2 0,265 9,8 26 000 38 000 0,14 S71910 CB/P4A HB50 /S 7CE1
72 12 7,61 6,2 0,265 9,8 30 000 45 000 0,13 S71910 CB/HCP4A HB50 /S/NS 7CE1
72 12 7,28 5,85 0,25 – 22 000 36 000 0,14 S71910 ACB/P4A HB50 /S 7CE3
72 12 7,28 5,85 0,25 – 28 000 43 000 0,13 S71910 ACB/HCP4A HB50 /S/NS 7CE3
80 16 9,95 7,8 0,335 9,7 24 000 36 000 0,29 S7010 CB/P4A HX50 /S 7CE1
80 16 9,95 7,8 0,335 9,7 28 000 45 000 0,28 S7010 CB/HCP4A HX50 /S/NS 7CE1
80 16 9,36 7,35 0,31 – 22 000 32 000 0,29 S7010 ACB/P4A HX50 /S 7CE3
80 16 9,36 7,35 0,31 – 26 000 40 000 0,28 S7010 ACB/HCP4A HX50 /S/NS 7CE3
1) The basic dynamic load ratings listed in the product tables are calculated in accordance with ISO 281:2007 and cannot be compared with ratings calculated
by other calculation methods.
2) Applicable to open bearings only
3) Applicable to sealed bearings only
4) For designations of open bearings and other variants, refer to table 15 on pages 32 and 33.

34
 ra rb

ra ra

Da db da D b

Dimensions Abutment and fillet dimensions

d d1 D1 r1,2 r3,4 a C3 C2 C1 b da,db Da Db ra rb

~ ~ min min min max max max max

mm mm

30 36 43 0,3 0,15 12 – – – – 32 45 45 0,3 0,15

36 43 0,3 0,15 12 – – – – 32 45 45 0,3 0,15
36 43 0,3 0,15 16 – – – – 32 45 45 0,3 0,15
36 43 0,3 0,15 16 – – – – 32 45 45 0,3 0,15
39,5 47,2 1 0,6 12 – – – – 34,6 50,4 50,4 1 0,6
39,5 47,2 1 0,6 12 – – – – 34,6 50,4 50,4 1 0,6
39,5 47,2 1 0,6 16 – – – – 34,6 50,4 50,4 1 0,6
39,5 47,2 1 0,6 16 – – – – 34,6 50,4 50,4 1 0,6

35 42,5 49,5 0,6 0,3 14 – – – – 38,2 51,8 51,8 0,6 0,3

42,5 49,5 0,6 0,3 14 – – – – 38,2 51,8 51,8 0,6 0,3
42,5 49,5 0,6 0,3 18 – – – – 38,2 51,8 51,8 0,6 0,3
42,5 49,5 0,6 0,3 18 – – – – 38,2 51,8 51,8 0,6 0,3
45,5 53,3 1 0,6 14 – – – – 39,6 57,4 57,4 1 0,6
45,5 53,3 1 0,6 14 – – – – 39,6 57,4 57,4 1 0,6
45,5 53,3 1 0,6 18 – – – – 39,6 57,4 57,4 1 0,6
45,5 53,3 1 0,6 18 – – – – 39,6 57,4 57,4 1 0,6

40 48,5 55,6 0,6 0,3 15 2,8 1,7 5,9 2 43,2 58,8 58,8 0,6 0,3
48,5 55,6 0,6 0,3 15 2,8 1,7 5,9 2 43,2 58,8 58,8 0,6 0,3
48,5 55,6 0,6 0,3 20 2,8 1,7 5,9 2 43,2 58,8 58,8 0,6 0,3
48,5 55,6 0,6 0,3 20 2,8 1,7 5,9 2 43,2 58,8 58,8 0,6 0,3
51 58,8 1 0,6 15 3,6 2,6 7,8 1,5 44,6 63,4 63,4 1 0,6
51 58,8 1 0,6 15 3,6 2,6 7,8 1,5 44,6 63,4 63,4 1 0,6
51 58,8 1 0,6 20 3,6 2,6 7,8 1,5 44,6 63,4 63,4 1 0,6
51 58,8 1 0,6 20 3,6 2,6 7,8 1,5 44,6 63,4 63,4 1 0,6

45 53,5 61,8 0,6 0,3 16 2,8 1,7 5,9 2 48,2 64,8 64,8 0,6 0,3
53,5 61,8 0,6 0,3 16 2,8 1,7 5,9 2 48,2 64,8 64,8 0,6 0,3
53,5 61,8 0,6 0,3 22 2,8 1,7 5,9 2 48,2 64,8 64,8 0,6 0,3
53,5 61,8 0,6 0,3 22 2,8 1,7 5,9 2 48,2 64,8 64,8 0,6 0,3
56,5 65,5 1 0,6 16 3,6 2,6 8,6 1,5 49,6 70,4 70,4 1 0,6
56,5 65,5 1 0,6 16 3,6 2,6 8,6 1,5 49,6 70,4 70,4 1 0,6
56,5 65,5 1 0,6 22 3,6 2,6 8,6 1,5 49,6 70,4 70,4 1 0,6
56,5 65,5 1 0,6 22 3,6 2,6 8,6 1,5 49,6 70,4 70,4 1 0,6

50 58 66 0,6 0,3 17 2,8 1,7 5,9 5,9 53,2 68,8 68,8 0,6 0,3
58 66 0,6 0,3 17 2,8 1,7 5,9 5,9 53,2 68,8 68,8 0,6 0,3
58 66 0,6 0,3 23 2,8 1,7 5,9 5,9 53,2 68,8 68,8 0,6 0,3
58 66 0,6 0,3 23 2,8 1,7 5,9 5,9 53,2 68,8 68,8 0,6 0,3
61,5 70,7 1 0,6 17 2,6 2,6 8,6 1,5 54,6 75,4 75,4 1 0,6
61,5 70,7 1 0,6 17 2,6 2,6 8,6 1,5 54,6 75,4 75,4 1 0,6
61,5 70,7 1 0,6 23 2,6 2,6 8,6 1,5 54,6 75,4 75,4 1 0,6
61,5 70,7 1 0,6 23 2,6 2,6 8,6 1,5 54,6 75,4 75,4 1 0,6

35
Super-precision angular contact ball bearings
d 55 – 75 mm
B
r2 r4 C1
r1 r3 b
C3
r1 r1 C2
r2 r2

D D1 d d1

a Open variant for

Sealed variant Open variant ­direct oil lubrication

Principal dimensions Basic load ratings Fatigue Calculation Attainable speed Mass3) Designations of sealed bearings4)
dynamic1) static load limit factor when lubricating with SKF SNFA
grease oil-air2)
d D B C C0 Pu f0

mm kN kN – r/min kg –

55 80 13 9,95 8,15 0,345 9,8 22 000 34 000 0,19 S71911 CB/P4A HB55 /S 7CE1
80 13 9,95 8,15 0,345 9,8 28 000 43 000 0,18 S71911 CB/HCP4A HB55 /S/NS 7CE1
80 13 9,36 7,65 0,325 – 20 000 32 000 0,19 S71911 ACB/P4A HB55 /S 7CE3
80 13 9,36 7,65 0,325 – 24 000 38 000 0,18 S71911 ACB/HCP4A HB55 /S/NS 7CE3
90 18 14 11 0,465 9,7 22 000 32 000 0,42 S7011 CB/P4A HX55 /S 7CE1
90 18 14 11 0,465 9,7 26 000 40 000 0,40 S7011 CB/HCP4A HX55 /S/NS 7CE1
90 18 13,3 10,4 0,44 – 19 000 30 000 0,42 S7011 ACB/P4A HX55 /S 7CE3
90 18 13,3 10,4 0,44 – 24 000 36 000 0,40 S7011 ACB/HCP4A HX55 /S/NS 7CE3

60 85 13 10,4 8,8 0,375 9,8 22 000 32 000 0,20 S71912 CB/P4A HB60 /S 7CE1
85 13 10,4 8,8 0,375 9,8 26 000 40 000 0,19 S71912 CB/HCP4A HB60 /S/NS 7CE1
85 13 9,75 8,3 0,355 – 19 000 30 000 0,20 S71912 ACB/P4A HB60 /S 7CE3
85 13 9,75 8,3 0,355 – 22 000 36 000 0,19 S71912 ACB/HCP4A HB60 /S/NS 7CE3
95 18 14,6 12 0,51 9,7 19 000 30 000 0,45 S7012 CB/P4A HX60 /S 7CE1
95 18 14,6 12 0,51 9,7 24 000 36 000 0,43 S7012 CB/HCP4A HX60 /S/NS 7CE1
95 18 13,5 11,4 0,48 – 17 000 26 000 0,45 S7012 ACB/P4A HX60 /S 7CE3
95 18 13,5 11,4 0,48 – 22 000 32 000 0,43 S7012 ACB/HCP4A HX60 /S/NS 7CE3

65 90 13 10,6 9,5 0,4 9,9 20 000 30 000 0,22 S71913 CB/P4A HB65 /S 7CE1
90 13 10,6 9,5 0,4 9,9 24 000 36 000 0,20 S71913 CB/HCP4A HB65 /S/NS 7CE1
90 13 9,95 9 0,38 – 18 000 28 000 0,22 S71913 ACB/P4A HB65 /S 7CE3
90 13 9,95 9 0,38 – 22 000 34 000 0,20 S71913 ACB/HCP4A HB65 /S/NS 7CE3
100 18 15,6 12,9 0,55 9,7 18 000 28 000 0,47 S7013 CB/P4A HX65 /S 7CE1
100 18 15,6 12,9 0,55 9,7 22 000 34 000 0,45 S7013 CB/HCP4A HX65 /S/NS 7CE1
100 18 14,6 12,2 0,52 – 16 000 26 000 0,47 S7013 ACB/P4A HX65 /S 7CE3
100 18 14,6 12,2 0,52 – 19 000 30 000 0,45 S7013 ACB/HCP4A HX65 /S/NS 7CE3

70 100 16 13,5 12,2 0,52 9,9 18 000 28 000 0,36 S71914 CB/P4A HB70 /S 7CE1
100 16 13,5 12,2 0,52 9,9 22 000 32 000 0,34 S71914 CB/HCP4A HB70 /S/NS 7CE1
100 16 12,7 11,6 0,49 – 16 000 24 000 0,36 S71914 ACB/P4A HB70 /S 7CE3
100 16 12,7 11,6 0,49 – 19 000 30 000 0,34 S71914 ACB/HCP4A HB70 /S/NS 7CE3
110 20 19 16,3 0,695 9,6 17 000 26 000 0,47 S7014 CB/P4A HX70 /S 7CE1
110 20 19 16,3 0,695 9,6 20 000 30 000 0,63 S7014 CB/HCP4A HX70 /S/NS 7CE1
110 20 18,2 15,6 0,655 – 15 000 24 000 0,47 S7014 ACB/P4A HX70 /S 7CE3
110 20 18,2 15,6 0,655 – 18 000 28 000 0,63 S7014 ACB/HCP4A HX70 /S/NS 7CE3

75 105 16 14 13,2 0,56 9,9 17 000 26 000 0,38 S71915 CB/P4A HB75 /S 7CE1
105 16 14 13,2 0,56 9,9 20 000 30 000 0,36 S71915 CB/HCP4A HB75 /S/NS 7CE1
105 16 13,3 12,5 0,52 – 15 000 24 000 0,38 S71915 ACB/P4A HB75 /S 7CE3
105 16 13,3 12,5 0,52 – 18 000 28 000 0,36 S71915 ACB/HCP4A HB75 /S/NS 7CE3
115 20 19,9 17,6 0,75 9,7 16 000 24 000 0,70 S7015 CB/P4A HX75 /S 7CE1
115 20 19,9 17,6 0,75 9,7 18 000 28 000 0,66 S7015 CB/HCP4A HX75 /S/NS 7CE1
115 20 19 16,6 0,71 – 14 000 22 000 0,70 S7015 ACB/P4A HX75 /S 7CE3
115 20 19 16,6 0,71 – 17 000 26 000 0,66 S7015 ACB/HCP4A HX75 /S/NS 7CE3
1) The basic dynamic load ratings listed in the product tables are calculated in accordance with ISO 281:2007 and cannot be compared with ratings calculated
by other calculation methods.
2) Applicable to open bearings only
3) Applicable to sealed bearings only
4) For designations of open bearings and other variants, refer to table 15 on pages 32 and 33.

36
 ra rb

ra ra

Da db da D b

Dimensions Abutment and fillet dimensions

d d1 D1 r1,2 r3,4 a C3 C2 C1 b da,db Da Db ra rb

~ ~ min min min max max max max

mm mm

55 64 73,2 1 0,3 19 3,8 1,7 6,5 2 59,6 75,4 75,4 1 0,3

64 73,2 1 0,3 19 3,8 1,7 6,5 2 59,6 75,4 75,4 1 0,3
64 73,2 1 0,3 26 3,8 1,7 6,5 2 59,6 75,4 75,4 1 0,3
64 73,2 1 0,3 26 3,8 1,7 6,5 2 59,6 75,4 75,4 1 0,3
68,2 79,3 1,1 0,6 19 4,3 2,8 9 2,2 61 84 84 1 0,6
68,2 79,3 1,1 0,6 19 4,3 2,8 9 2,2 61 84 84 1 0,6
68,2 79,3 1,1 0,6 26 4,3 2,8 9 2,2 61 84 84 1 0,6
68,2 79,3 1,1 0,6 26 4,3 2,8 9 2,2 61 84 84 1 0,6

60 69 78,3 1 0,3 19 3,8 1,7 6,5 2 64,6 80,4 80,4 1 0,3

69 78,3 1 0,3 19 3,8 1,7 6,5 2 64,6 80,4 80,4 1 0,3
69 78,3 1 0,3 27 3,8 1,7 6,5 2 64,6 80,4 80,4 1 0,3
69 78,3 1 0,3 27 3,8 1,7 6,5 2 64,6 80,4 80,4 1 0,3
73,2 84,3 1,1 0,6 19 4,3 2,8 9 2,2 66 89 89 1 0,6
73,2 84,3 1,1 0,6 19 4,3 2,8 9 2,2 66 89 89 1 0,6
73,2 84,3 1,1 0,6 27 4,3 2,8 9 2,2 66 89 89 1 0,6
73,2 84,3 1,1 0,6 27 4,3 2,8 9 2,2 66 89 89 1 0,6

65 74 83,4 1 0,3 20 3,8 1,7 6,5 2 69,6 85,4 85,4 1 0,3

74 83,4 1 0,3 20 3,8 1,7 6,5 2 69,6 85,4 85,4 1 0,3
74 83,4 1 0,3 28 3,8 1,7 6,5 2 69,6 85,4 85,4 1 0,3
74 83,4 1 0,3 28 3,8 1,7 6,5 2 69,6 85,4 85,4 1 0,3
78 89,6 1,1 0,6 20 4,3 2,8 9,7 1,5 71 94 94 1 0,6
78 89,6 1,1 0,6 20 4,3 2,8 9,7 1,5 71 94 94 1 0,6
78 89,6 1,1 0,6 28 4,3 2,8 9,7 1,5 71 94 94 1 0,6
78 89,6 1,1 0,6 28 4,3 2,8 9,7 1,5 71 94 94 1 0,6

70 81 91,6 1 0,3 22 3,8 1,7 8,6 1,5 74,6 95,4 95,4 1 0,3
81 91,6 1 0,3 22 3,8 1,7 8,6 1,5 74,6 95,4 95,4 1 0,3
81 91,6 1 0,3 31 3,8 1,7 8,6 1,5 74,6 95,4 95,4 1 0,3
81 91,6 1 0,3 31 3,8 1,7 8,6 1,5 74,6 95,4 95,4 1 0,3
85 97,8 1,1 0,6 22 4,4 2,9 10,9 1,5 76 104 104 1 0,6
85 97,8 1,1 0,6 22 4,4 2,9 10,9 1,5 76 104 104 1 0,6
85 97,8 1,1 0,6 31 4,4 2,9 10,9 1,5 76 104 104 1 0,6
85 97,8 1,1 0,6 31 4,4 2,9 10,9 1,5 76 104 104 1 0,6

75 86 97,5 1 0,6 22 3,8 2,7 8,6 1,5 79,6 100 100 1 0,3
86 97,5 1 0,6 22 3,8 2,7 8,6 1,5 79,6 100 100 1 0,3
86 97,5 1 0,6 32 3,8 2,7 8,6 1,5 79,6 100 100 1 0,3
86 97,5 1 0,6 32 3,8 2,7 8,6 1,5 79,6 100 100 1 0,3
90 102,8 1,1 0,6 22 4,4 2,9 10,9 1,5 81 109 109 1 0,6
90 102,8 1,1 0,6 22 4,4 2,9 10,9 1,5 81 109 109 1 0,6
90 102,8 1,1 0,6 32 4,4 2,9 10,9 1,5 81 109 109 1 0,6
90 102,8 1,1 0,6 32 4,4 2,9 10,9 1,5 81 109 109 1 0,6

37
Super-precision angular contact ball bearings
d 80 – 100 mm
B
r2 r4 C1
r1 r3 b
C3
r1 r1 C2
r2 r2

D D1 d d1

a Open variant for

Sealed variant Open variant ­direct oil lubrication

Principal dimensions Basic load ratings Fatigue Calculation Attainable speed Mass3) Designations of sealed bearings4)
dynamic1) static load limit factor when lubricating with SKF SNFA
grease oil-air2)
d D B C C0 Pu f0

mm kN kN – r/min kg –

80 110 16 15,6 14,6 0,63 9,9 16 000 24 000 0,40 S71916 CB/P4A HB80 /S 7CE1
110 16 15,6 14,6 0,63 9,9 19 000 30 000 0,37 S71916 CB/HCP4A HB80 /S/NS 7CE1
110 16 14,8 14 0,585 – 14 000 22 000 0,40 S71916 ACB/P4A HB80 /S 7CE3
110 16 14,8 14 0,585 – 17 000 26 000 0,37 S71916 ACB/HCP4A HB80 /S/NS 7CE3
125 22 26,5 22,8 0,95 9,6 14 000 20 000 0,92 S7016 CB/P4A HX80 /S 7CE1
125 22 26,5 22,8 0,95 9,6 17 000 26 000 0,86 S7016 CB/HCP4A HX80 /S/NS 7CE1
125 22 25,1 21,6 0,9 – 12 000 19 000 0,92 S7016 ACB/P4A HX80 /S 7CE3
125 22 25,1 21,6 0,9 – 15 000 22 000 0,86 S7016 ACB/HCP4A HX80 /S/NS 7CE3

85 120 18 16,3 16,3 0,68 10 15 000 22 000 0,59 S71917 CB/P4A HB85 /S 7CE1
120 18 16,3 16,3 0,68 10 18 000 28 000 0,56 S71917 CB/HCP4A HB85 /S/NS 7CE1
120 18 15,3 15,3 0,64 – 13 000 20 000 0,59 S71917 ACB/P4A HB85 /S 7CE3
120 18 15,3 15,3 0,64 – 16 000 24 000 0,56 S71917 ACB/HCP4A HB85 /S/NS 7CE3
130 22 27 23,6 0,965 9,6 13 000 20 000 0,96 S7017 CB/P4A HX85 /S 7CE1
130 22 27 23,6 0,965 9,6 16 000 24 000 0,90 S7017 CB/HCP4A HX85 /S/NS 7CE1
130 22 25,1 22,4 0,915 – 12 000 18 000 0,96 S7017 ACB/P4A HX85 /S 7CE3
130 22 25,1 22,4 0,915 – 14 000 22 000 0,90 S7017 ACB/HCP4A HX85 /S/NS 7CE3

90 125 18 17,8 17,6 0,72 10 14 000 22 000 0,61 S71918 CB/P4A HB90 /S 7CE1
125 18 17,8 17,6 0,72 10 16 000 26 000 0,58 S71918 CB/HCP4A HB90 /S/NS 7CE1
125 18 16,8 16,6 0,68 – 12 000 19 000 0,61 S71918 ACB/P4A HB90 /S 7CE3
125 18 16,8 16,6 0,68 – 15 000 22 000 0,58 S71918 ACB/HCP4A HB90 /S/NS 7CE3
140 24 29,1 25 0,98 9,7 12 000 19 000 1,25 S7018 CB/P4A HX90 /S 7CE1
140 24 29,1 25 0,98 9,7 15 000 24 000 1,20 S7018 CB/HCP4A HX90 /S/NS 7CE1
140 24 27 23,6 0,93 – 11 000 17 000 1,25 S7018 ACB/P4A HX90 /S 7CE3
140 24 27 23,6 0,93 – 13 000 20 000 1,20 S7018 ACB/HCP4A HX90 /S/NS 7CE3

95 130 18 18,2 18,6 0,75 10 13 000 20 000 0,64 S71919 CB/P4A HB95 /S 7CE1
130 18 18,2 18,6 0,75 10 16 000 24 000 0,61 S71919 CB/HCP4A HB95 /S/NS 7CE1
130 18 17,2 17,6 0,71 – 12 000 18 000 0,64 S71919 ACB/P4A HB95 /S 7CE3
130 18 17,2 17,6 0,71 – 14 000 22 000 0,61 S71919 ACB/HCP4A HB95 /S/NS 7CE3
145 24 29,6 26 1 9,7 12 000 18 000 1,30 S7019 CB/P4A HX95 /S 7CE1
145 24 29,6 26 1 9,7 14 000 22 000 1,20 S7019 CB/HCP4A HX95 /S/NS 7CE1
145 24 27,6 24,5 0,95 – 11 000 16 000 1,30 S7019 ACB/P4A HX95 /S 7CE3
145 24 27,6 24,5 0,95 – 13 000 19 000 1,20 S7019 ACB/HCP4A HX95 /S/NS 7CE3

100 140 20 21,6 22,4 0,865 10 12 000 19 000 0,88 S71920 CB/P4A HB100 /S 7CE1
140 20 21,6 22,4 0,865 10 15 000 24 000 0,83 S71920 CB/HCP4A HB100 /S/NS 7CE1
140 20 20,8 21,2 0,815 – 11 000 17 000 0,88 S71920 ACB/P4A HB100 /S 7CE3
140 20 20,8 21,2 0,815 – 13 000 20 000 0,83 S71920 ACB/HCP4A HB100 /S/NS 7CE3
150 24 29,6 27 1,02 9,8 11 000 17 000 1,40 S7020 CB/P4A HX100 /S 7CE1
150 24 29,6 27 1,02 9,8 13 000 20 000 1,30 S7020 CB/HCP4A HX100 /S/NS 7CE1
150 24 28,1 25,5 0,98 – 10 000 15 000 1,40 S7020 ACB/P4A HX100 /S 7CE3
150 24 28,1 25,5 0,98 – 12 000 18 000 1,30 S7020 ACB/HCP4A HX100 /S/NS 7CE3
1) The basic dynamic load ratings listed in the product tables are calculated in accordance with ISO 281:2007 and cannot be compared with ratings calculated
by other calculation methods.
2) Applicable to open bearings only
3) Applicable to sealed bearings only
4) For designations of open bearings and other variants, refer to table 15 on pages 32 and 33.

38
 ra rb

ra ra

Da db da D b

Dimensions Abutment and fillet dimensions

d d1 D1 r1,2 r3,4 a C3 C2 C1 b da,db Da Db ra rb

~ ~ min min min max max max max

mm mm

80 90,7 102,2 1 0,6 25 3,8 2,7 8,6 2 84,6 105 105 1 0,3
90,7 102,2 1 0,6 25 3,8 2,7 8,6 2 84,6 105 105 1 0,3
90,7 102,2 1 0,6 35 3,8 2,7 8,6 2 84,6 105 105 1 0,3
90,7 102,2 1 0,6 35 3,8 2,7 8,6 2 84,6 105 105 1 0,3
96,7 111,4 1,1 0,6 25 4,7 3,2 11,1 2,5 86 119 119 1 0,6
96,7 111,4 1,1 0,6 25 4,7 3,2 11,1 2,5 86 119 119 1 0,6
96,7 111,4 1,1 0,6 35 4,7 3,2 11,1 2,5 86 119 119 1 0,6
96,7 111,4 1,1 0,6 35 4,7 3,2 11,1 2,5 86 119 119 1 0,6

85 98,2 110,2 1,1 0,6 26 4,5 2,9 9,3 2,2 91 114 114 1 0,6
98,2 110,2 1,1 0,6 26 4,5 2,9 9,3 2,2 91 114 114 1 0,6
98,2 110,2 1,1 0,6 36 4,5 2,9 9,3 2,2 91 114 114 1 0,6
98,2 110,2 1,1 0,6 36 4,5 2,9 9,3 2,2 91 114 114 1 0,6
101,7 116,4 1,1 0,6 26 4,7 3,2 11,1 2,5 91 124 124 1 0,6
101,7 116,4 1,1 0,6 26 4,7 3,2 11,1 2,5 91 124 124 1 0,6
101,7 116,4 1,1 0,6 36 4,7 3,2 11,1 2,5 91 124 124 1 0,6
101,7 116,4 1,1 0,6 36 4,7 3,2 11,1 2,5 91 124 124 1 0,6

90 103 115 1,1 0,6 28 4,5 2,9 9,3 2,2 96 119 119 1 0,6
103 115 1,1 0,6 28 4,5 2,9 9,3 2,2 96 119 119 1 0,6
103 115 1,1 0,6 39 4,5 2,9 9,3 2,2 96 119 119 1 0,6
103 115 1,1 0,6 39 4,5 2,9 9,3 2,2 96 119 119 1 0,6
108,7 125 1,5 1 28 5,2 4,2 13,4 2,2 97 133 133 1,5 1
108,7 125 1,5 1 28 5,2 4,2 13,4 2,2 97 133 133 1,5 1
108,7 125 1,5 1 39 5,2 4,2 13,4 2,2 97 133 133 1,5 1
108,7 125 1,5 1 39 5,2 4,2 13,4 2,2 97 133 133 1,5 1

95 108 120,7 1,1 0,6 28 4,5 2,9 9,3 2,2 101 124 124 1 0,6
108 120,7 1,1 0,6 28 4,5 2,9 9,3 2,2 101 124 124 1 0,6
108 120,7 1,1 0,6 40 4,5 2,9 9,3 2,2 101 124 124 1 0,6
108 120,7 1,1 0,6 40 4,5 2,9 9,3 2,2 101 124 124 1 0,6
113,7 130 1,5 1 28 5,2 4,2 13,4 2,2 102 138 138 1,5 1
113,7 130 1,5 1 28 5,2 4,2 13,4 2,2 102 138 138 1,5 1
113,7 130 1,5 1 40 5,2 4,2 13,4 2,2 102 138 138 1,5 1
113,7 130 1,5 1 40 5,2 4,2 13,4 2,2 102 138 138 1,5 1

100 115 128,7 1,1 0,6 29 4,5 2,9 10,9 2,2 106 134 134 1 0,6
115 128,7 1,1 0,6 29 4,5 2,9 10,9 2,2 106 134 134 1 0,6
115 128,7 1,1 0,6 41 4,5 2,9 10,9 2,2 106 134 134 1 0,6
115 128,7 1,1 0,6 41 4,5 2,9 10,9 2,2 106 134 134 1 0,6
118,7 135 1,5 1 29 5,2 4,2 13,4 2,2 107 143 143 1,5 1
118,7 135 1,5 1 29 5,2 4,2 13,4 2,2 107 143 143 1,5 1
118,7 135 1,5 1 41 5,2 4,2 13,4 2,2 107 143 143 1,5 1
118,7 135 1,5 1 41 5,2 4,2 13,4 2,2 107 143 143 1,5 1

39
Super-precision angular contact ball bearings
d 110 – 120 mm
B
r2 r4 C1
r1 r3 b
C3
r1 r1 C2
r2 r2

D D1 d d1

a Open variant for

Sealed variant Open variant ­direct oil lubrication

Principal dimensions Basic load ratings Fatigue Calculation Attainable speed Mass3) Designations of sealed bearings4)
dynamic1) static load limit factor when lubricating with SKF SNFA
grease oil-air2)
d D B C C0 Pu f0

mm kN kN – r/min kg –

110 150 20 26 27 1 10 11 000 17 000 0,93 S71922 CB/P4A HB110 /S 7CE1

150 20 26 27 1 10 14 000 22 000 0,87 S71922 CB/HCP4A HB110 /S/NS 7CE1
150 20 24,7 25,5 0,95 – 10 000 15 000 0,93 S71922 ACB/P4A HB110 /S 7CE3
150 20 24,7 25,5 0,95 – 12 000 19 000 0,87 S71922 ACB/HCP4A HB110 /S/NS 7CE3
170 28 37,1 36 1,29 9,7 10 000 16 000 2,20 S7022 CB/P4A HX110 /S 7CE1
170 28 37,1 36 1,29 9,7 12 000 19 000 2,10 S7022 CB/HCP4A HX110 /S/NS 7CE1
170 28 35,1 34 1,22 – 9 000 14 000 2,20 S7022 ACB/P4A HX110 /S 7CE3
170 28 35,1 34 1,22 – 11 000 16 000 2,10 S7022 ACB/HCP4A HX110 /S/NS 7CE3

120 165 22 27 30,5 1,08 10 10 000 16 000 1,30 S71924 CB/P4A HB120 /S 7CE1
165 22 27 30,5 1,08 10 12 000 20 000 1,20 S71924 CB/HCP4A HB120 /S/NS 7CE1
165 22 25,5 28,5 1,02 – 9 000 14 000 1,30 S71924 ACB/P4A HB120 /S 7CE3
165 22 25,5 28,5 1,02 – 11 000 17 000 1,20 S71924 ACB/HCP4A HB120 /S/NS 7CE3
180 28 37,7 39 1,34 9,8 9 500 14 000 2,35 S7024 CB/P4A HX120 /S 7CE1
180 28 37,7 39 1,34 9,8 11 000 17 000 2,20 S7024 CB/HCP4A HX120 /S/NS 7CE1
180 28 35,8 36,5 1,27 – 8 500 13 000 2,35 S7024 ACB/P4A HX120 /S 7CE3
180 28 35,8 36,5 1,27 – 10 000 15 000 2,20 S7024 ACB/HCP4A HX120 /S/NS 7CE3

1) The basic dynamic load ratings listed in the product tables are calculated in accordance with ISO 281:2007 and cannot be compared with ratings calculated
by other calculation methods.
2) Applicable to open bearings only
3) Applicable to sealed bearings only
4) For designations of open bearings and other variants, refer to table 15 on pages 32 and 33.

40
 ra rb

ra ra

Da db da D b

Dimensions Abutment and fillet dimensions

d d1 D1 r1,2 r3,4 a C3 C2 C1 b da,db Da Db ra rb

~ ~ min min min max max max max

mm mm

110 124,5 139 1,1 0,6 33 4,5 2,9 10,9 2,2 116 144 144 1 0,6
124,5 139 1,1 0,6 33 4,5 2,9 10,9 2,2 116 144 144 1 0,6
124,5 139 1,1 0,6 47 4,5 2,9 10,9 2,2 116 144 144 1 0,6
124,5 139 1,1 0,6 47 4,5 2,9 10,9 2,2 116 144 144 1 0,6
133,2 151,9 2 1 33 6,2 4,2 15,1 2,2 119 161 161 2 1
133,2 151,9 2 1 33 6,2 4,2 15,1 2,2 119 161 161 2 1
133,2 151,9 2 1 47 6,2 4,2 15,1 2,2 119 161 161 2 1
133,2 151,9 2 1 47 6,2 4,2 15,1 2,2 119 161 161 2 1

120 137 151,9 1,1 0,6 34 4,5 2,9 11,9 2,2 126 159 159 1 0,6
137 151,9 1,1 0,6 34 4,5 2,9 11,9 2,2 126 159 159 1 0,6
137 151,9 1,1 0,6 49 4,5 2,9 11,9 2,2 126 159 159 1 0,6
137 151,9 1,1 0,6 49 4,5 2,9 11,9 2,2 126 159 159 1 0,6
143,2 161,9 2 1 34 6,3 4,3 15,1 2,2 129 171 171 2 1
143,2 161,9 2 1 34 6,3 4,3 15,1 2,2 129 171 171 2 1
143,2 161,9 2 1 49 6,3 4,3 15,1 2,2 129 171 171 2 1
143,2 161,9 2 1 49 6,3 4,3 15,1 2,2 129 171 171 2 1

41
Setting the highest standard
for precision bearings
SKF together with SNFA are developing
a new, improved generation of super-­
precision bearings. By combining the best
design criteria from both brands, the new
SKF-SNFA assortment delivers improved
accuracy and extended bearing service life
when compared to previous designs.
Table 1 on pages 44 and 45 provides an
overview of the growing, new assortment of
SKF-SNFA ­super-precision bearings. The
full assortment of SKF high-precision bear-
ings will ultimately be replaced completely
by super-precision bearings.

42
Other SKF-SNFA
super-precision bearings
Super-precision Super-precision Double direction angular
contact thrust ball bearings
angular contact ball angular contact thrust
bearings in the 718 ball bearings for screw Double direction angular contact thrust ball
bearings in the BEAS series have been de-
(SEA) series drives veloped for machine tool applications where
space is tight and easy mounting is required. D
SKF-SNFA super-precision angular contact
Single direction angular The bearings are available for shaft diam-
ball bearings in the 718 (SEA) series provide contact thrust ball bearings eters ranging from 8 to 30 mm. Bearings in
optimum performance in applications where Single direction angular contact thrust ball the BEAM series, which can accommodate
a low cross section and high degree of rigid- bearings in the BSA and BSD (BS) series are shaft diameters ranging from 12 to 60 mm,
ity, speed and superior accuracy are critical available for shaft diameters ranging from can be bolt-mounted to an associated
design parameters. They are particularly 12 to 75 mm. These bearings are charac- component.
suitable for machine tool applications, multi- terized by superior axial stiffness and high
spindle drilling heads, robotic arms, meas- axial load carrying capacity.
uring devices, racing car wheels and other Cartridge units with a flanged
precision applications. housing
The standard assortment includes
­all-steel bearings and hybrid bearings and Cartridge units are another solution for sim-
­accommodates shaft diameters ranging ple and quick mounting. Units in the FBSA
from 10 to 160 mm. To balance the need (BSDU and BSQU) series incorporate SKF-
for rotational speed and system rigidity, SNFA single direction angular contact thrust
the bearings are manufactured to different ball bearings and can accommodate shaft
preload classes. diameters ranging from 20 to 60 mm.

43
 Overview of the transition to SKF-SNFA super-precision bearings

ISO Bearing type and design Variant Previous assortment

Dimension SKF bearings SKF publication
Series in the series

18 Angular contact ball Open All-steel – –

bearings: Basic design –

Hybrid –
–

19 Angular contact ball Open All-steel – High-precision bearings

bearings: High-speed, 719 FB (Publication No. 6002)
B design 719 DB

Hybrid –
C719 FB
C719 DB

Sealed All-steel –
S719 FB
S719 DB

Hybrid –
SC719 FB
SC719 DB

10 Angular contact ball Open All-steel – High-precision bearings

bearings: High-speed, 70 FB (Publication No. 6002)
B design 70 DB

Hybrid –
C70 FB
C70 DB

Sealed All-steel –
S70 FB
S70 DB

Hybrid –
SC70 FB
SC70 DB

02 Angular contact thrust ball Open All-steel BSA 2 High-precision bearings

bearings: Single direction (Publication No. 6002)
Sealed All-steel BSA 2 2RS
BSA 2 2Z
–

03 Angular contact thrust ball Open All-steel BSA 3 High-precision bearings

bearings: Single direction (Publication No. 6002)
Sealed All-steel BSA 3 2RS
BSA 3 2Z
–

– Angular contact thrust ball Open All-steel BSD High-precision bearings

(Non- bearings: Single direction (Publication No. 6002)
standar­ized) Sealed All-steel BSD 2RS
BSD 2Z
–

Angular contact thrust ball Sealed All-steel BEAS

bearings: Double direction BEAM

Cartridge unit with angular Sealed All-steel FBSA

contact thrust ball bearings FBSD

44
 Table 1

New assortment
SNFA bearings SNFA publication SKF-SNFA bearings in the series SKF publication
in the series

SEA 1 SNFA General Catalogue 718 CD (SEA CE1) Super-precision angular contact ball bearings:
SEA 3 718 ACD (SEA CE3) 718 (SEA) series (Publication No. 6810)

SEA /NS CE1 718 CD/HC (SEA /NS CE1)

SEA /NS CE3 718 ACD/HC (SEA /NS CE3)

HB CE1 SNFA General Catalogue 719 CB (HB CE1) Super-precision angular contact ball bearings:
HB CE2 719 FB (HB CE2) High-speed, B design, sealed as standard
HB CE3 719 ACB (HB CE3) (Publication No. 6939)

HB /NS CE1 719 CB/HC (HB /NS CE1)

HB /NS CE2 719 FB/HC (HB /NS CE2)
HB /NS CE3 719 ACB/HC (HB /NS CE3)
D
HB /S CE1 S719 CB (HB /S CE1)
HB /S CE2 S719 FB (HB /S CE2)
HB /S CE3 S719 ACB (HB /S CE3)

HB /S/NS CE1 S719 CB/HC (HB /S/NS CE1)

HB /S/NS CE2 S719 FB/HC (HB /S/NS CE2)
HB /S/NS CE3 S719 ACB/HC (HB /S/NS CE3)

HX CE1 SNFA General Catalogue 70 CB (HX CE1) Super-precision angular contact ball bearings:
HX CE2 and previous publications 70 FB (HX CE2) High-speed, B design, sealed as standard
HX CE3 70 ACB (HX CE3) (Publication No. 6939)

HX /NS CE1 70 CB/HC (HX /NS CE1)

HX /NS CE2 70 FB/HC (HX /NS CE2)
HX /NS CE3 70 ACB/HC (HX /NS CE3)

HX /S CE1 S70 CB (HX /S CE1)

HX /S CE2 S70 FB (HX /S CE2)
HX /S CE3 S70 ACB (HX /S CE3)

HX /S/NS CE1 S70 CB/HC (HX /S/NS CE1)

HX /S/NS CE2 S70 FB/HC (HX /S/NS CE2)
HX /S/NS CE3 S70 ACB/HC (HX /S/NS CE3)

BS 200 SNFA General Catalogue BSA 2 (BS 200) Super-precision angular contact thrust ball
bearings for screw drives (Publication No. 6570)
– BSA 2 2RS (BS 200/C)
– BSA 2 2Z (BS 200/Z)
BS 200/S BSA 2 2RZ (BS 200/S)

– BSA 3 (BS 3) Super-precision angular contact thrust ball

bearings for screw drives (Publication No. 6570)
– BSA 3 2RS (BS 3 /C)
– BSA 3 2Z (BS 3 /Z)
– BSA 3 2RZ (BS 3 /S)

BS / SNFA General Catalogue BSD (BS ../) Super-precision angular contact thrust ball
bearings for screw drives (Publication No. 6570)
– BSD 2RS (BS ../C)
– BSD 2Z (BS ../Z)
BS /S BSD 2RZ (BS ../S)

– BEAS (BEAS)
– BEAM (BEAM)

BSDU, BSQU FBSA (BSDU, BSQU)

– –

45
SKF – the knowledge engineering
company
From the company that invented the self- The SKF Group is globally certified to ISO
aligning ball bearing more than 100 years 14001, the international standard for envir-
ago, SKF has evolved into a knowledge onmental management, as well as OHSAS
engineering company that is able to draw on 18001, the health and safety management
five technology platforms to create unique standard. Individual divisions have been
solutions for its customers. These platforms approved for quality certification in accord-
include bearings, bearing units and seals, of ance with ISO 9001 and other customer
course, but extend to other areas including: specific requirements.
lubricants and lubrication systems, critical With over 100 manufacturing sites world-
© Airbus – photo: exm company, H. Goussé
for long bearing life in many applications; wide and sales companies in 70 countries,
mechatronics that combine mechanical and SKF is a truly international corporation. In Evolving by-wire technology
electronics knowledge into systems for more addition, our distributors and dealers in SKF has a unique expertise in fast-growing by-
wire technology, from fly-by-wire, to drive-by-
effective linear motion and sensorized solu- some 15 000 locations around the world, wire, to work-by-wire. SKF pioneered practical fly-
tions; and a full range of services, from de- an e-business marketplace and a global by-wire technology and is a close working partner
sign and logistics support to conditioning distribution system put SKF close to custom- with all aerospace industry leaders. As an example,
virtually all aircraft of the Airbus design use SKF
monitoring and reliability systems. ers for the supply of both products and by-wire systems for cockpit flight control.
Though the scope has broadened, SKF services. In essence, SKF solutions are avail-
continues to maintain the world’s leadership able wherever and whenever customers
in the design, manufacture and marketing of need them. Overall, the SKF brand and the
rolling bearings, as well as complementary corporation are stronger than ever. As the
products such as radial seals. SKF also holds knowledge engineering company, we stand
an increasingly important position in the ready to serve you with world-class product
market for linear motion products, high- competencies, intellectual resources, and
precision aerospace bearings, machine tool the vision to help you succeed.
spindles and plant maintenance services.

SKF is also a leader in automotive by-wire tech-

nology, and has partnered with automotive engin-
eers to develop two concept cars, which employ
SKF mechatronics for steering and braking. Fur-
ther by-wire development has led SKF to produce
an all-electric forklift truck, which uses mecha-
tronics rather than hydraulics for all controls.

Bearings Lubrication
Seals
and units systems

Mechatronics Services

46
Harnessing wind power
The growing industry of wind-generated electric power provides a source of
clean, green electricity. SKF is working closely with global industry leaders to
develop efficient and trouble-free turbines, providing a wide range of large,
highly specialized bearings and condition monitoring systems to extend equip-
ment life of wind farms located in even the most remote and inhospitable
environments.

Working in extreme environments

In frigid winters, especially in northern countries, extreme sub-zero tempera-
tures can cause bearings in railway axleboxes to seize due to lubrication star-
vation. SKF created a new family of synthetic lubricants formulated to retain
their lubrication viscosity even at these extreme temperatures. SKF knowledge
enables manufacturers and end user customers to overcome the performance
issues resulting from extreme temperatures, whether hot or cold. For example,
SKF products are at work in diverse environments such as baking ovens and
instant freezing in food processing plants.
D

Developing a cleaner cleaner

The electric motor and its bearings are the heart of many household appli-
ances. SKF works closely with appliance manufacturers to improve their prod-
ucts’ performance, cut costs, reduce weight, and reduce energy consumption.
A recent example of this cooperation is a new generation of vacuum cleaners
with substantially more suction. SKF knowledge in the area of small bearing
technology is also applied to manufacturers of power tools and office
equipment.

Maintaining a 350 km/h R&D lab

In addition to SKF’s renowned research and development facilities in Europe
and the United States, Formula One car racing provides a unique environment
for SKF to push the limits of bearing technology. For over 50 years, SKF prod-
ucts, engineering and knowledge have helped make Scuderia Ferrari a formid-
able force in F1 racing. (The average racing Ferrari utilizes more than 150 SKF
components.) Lessons learned here are applied to the products we provide to
automakers and the aftermarket worldwide.

Delivering Asset Efficiency Optimization

Through SKF Reliability Systems, SKF provides a comprehensive range of
asset efficiency products and services, from condition monitoring hardware
and software to maintenance strategies, engineering assistance and machine
reliability programmes. To optimize efficiency and boost productivity, some
industrial facilities opt for an Integrated Maintenance Solution, in which SKF
delivers all services under one fixed-fee, performance-based contract.

Planning for sustainable growth

By their very nature, bearings make a positive contribution to the natural
environment, enabling machinery to operate more efficiently, consume less
power, and require less lubrication. By raising the performance bar for our
own products, SKF is enabling a new generation of high-efficiency products
and equipment. With an eye to the future and the world we will leave to our
children, the SKF Group policy on environment, health and safety, as well as
the manufacturing techniques, are planned and implemented to help protect
and preserve the earth’s limited natural resources. We remain committed to
sustainable, environmentally responsible growth.

47
 The Power of Knowledge Engineering

Seals
Bearings Lubrication Drawing on five areas of competence and application-specific expertise amassed over more than 100
and units systems years, SKF brings innovative solutions to OEMs and production facilities in every major industry world-
wide. These five competence areas include bearings and units, seals, lubrication systems, mechatronics
(combining mechanics and electronics into intelligent systems), and a wide range of services, from 3-D
Mechatronics Services
computer modelling to advanced condition monitoring and reliability and asset management systems.
A global presence provides SKF customers uniform quality standards and worldwide product availability.

® SKF and SNFA are registered trademarks of the SKF Group.

© SKF Group 2009
The contents of this publication are the copyright of the publisher and may not be reproduced (even extracts) unless prior written permis-
sion is granted. Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be
accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained herein.
Publication 6939/I EN  ·  June 2009
This publication supersedes all information about SKF bearings in the 719 .. B and 70 .. B series in the SKF publication 6002 EN
­High-precision bearings, and SNFA bearings in the HB and HX series in the SNFA General Catalogue.
Printed in Sweden on environmentally friendly paper.

skf.com