MACHINING: TURNING AND SHAPING

GENERAL SAFETY PRECAUTIONS

1. Be sure that all the machines have effective and properly working guards that are
always in place when machines are operating.
2. Replace guards immediately after any repairs.
3. Do not attempt to oil, clean, adjust or repair any machine while it is running. Stop
the machine and lock the power switch in the off position.
4. Do not operate any machines unless authorized to do so by your instructor.
5. Even after the power is off, do not leave the machine until it has stopped running.
6. Do not try to stop the machines with your hands or body.
7. Always see that work and cutting tools on any machine are clamped securely
before starting.
8. Keep the floor clear of metal chips or curls and waste pieces.
9. Get help for handling long or heavy pieces of work.
10. When working with others, only one should operate the machine or switches.
11. Do not lean against the machines.
12. No horse playing.
13. Concentrate on the work and do not talk unnecessarily while operating the
machine.
14. Do not talk to others when they are operating the machine.
15. Get first aid immediately for any injury.
16. Be sure you have sufficient light to see clearly.

SAFETY (GRINDER/ PEDESTAL TYPE)

1. Stand to one side out of line of wheel when starting it up.

2. The face of the wheel must be flat and free from grooves.
3. Work should be feed slowly and gradually.
4. Make sure that the tool rest is only 1/8in from the face of the wheel.
5. Do not set tool rest while machine is in motion.
6. Use face of wheel only, unless it is designed for grinding on the side; otherwise,
side pressure may break the wheel. Use the entire face of the wheel to avoid
grooving.
7. Stop wheel if it chatters or vibrates excessively.
8. All wheels should be tested for soundness.
 9. Hold the job against wheel firmly so that it will not slip out of the hand and cause
hands and fingers to come in contact to the wheel.
10. Use clamp or other holding devices for holding short pieces.
11. Always use face shield or goggles even of grinder is provided with protective
glass shields.

CLOTHING AND SAFETY EQUIPMENT

1. Always wear safety glasses, goggles or face shields designed for the type of
work when operating any machines.
2. Wear clothing suited for the job. Wear shoes with thick soles – safety shoes if
heavy work is being done.
3. Do not wear rings, watches, bracelets, or other jewellery that could get caught in
moving machinery.
4. Do not wear neckties or loose or torn clothing of any kind.
5. Wear shirts or jumpers with sleeves cut off or rolled above the elbows.
6. Always remove gloves before turning on or operating any machine. If material is
rough or sharp and gloves must be worn, place or handle material with machine
turned off.

HOUSEKEEPING

1. Keep floors free of oil, grease, or any other liquid. Clean up spilled liquids
immediately; they are slipping hazards.
2. Aisles should be cleared at all times to avoid tripping or other accidents.
3. Store material in such a way that they cannot became tripping hazards.
4. Do not leave tools or work on the table of the machine even if the machine is not
running. Tools or work may fall off and cause toe or foot injury.
5. Put tools away when not in use.
6. Place all scrap in scrap boxes.

NOTE: Work safely at all times.

Safety is everybody’s concern.

SHARPENING TOOLS
 For some tools it is very important to keep them sharp at all times. Common
tools, such as scribers, center punches, chisels, drill bits, tool bits for lathe
machine needs to be sharpened every time you feel that they do not cut well.

Bench Grinder or Pedestal Grinder

 The bench grinder is used for the sharpening of cutting tools and the rough
grinding of metal. Because the work is usually held in the hand, this type of
grinding is sometimes called “offhand grinding”.
 The bench grinder is mounted on a bench while the pedestal grinder being a
larger machine is fastened to the floor. Both types consist of an electric motor
with a coarse abrasive grinding wheel for the fast removal of metal while the
other is a fine abrasive wheel for finish grinding.
 The grinding wheels are normally made of Aluminum−Oxide or Silicon−Carbide.
 Aluminum−Carbide is used to grind High−Tensile−Strength Materials.
 Silicon−Carbide is used to grind Low−Tensile−Strength Materials.

Parts of a grinder
 The wheel guards give the necessary protection while grinding
 The tool rest provide a rest for either the work or hands while grinding
 The eye shield is an additional protection for the eyes and should be used

Redressing the grinding wheels

When a grinding wheel is used, several things can happen to it:
 Grooves become worn in the face of the wheel
 The abrasive grains will lose its cutting action
 Small metal particles imbed themselves in the wheel, causing it to become
loaded or clogged.
Use from time to time a disc type dresser or a dressing stone to remove the grooves
and the metal particles. This will also re−sharpen the abrasive grains.
Safety precautions (grinder/ pedestal type)

12. Stand to one side out of line of wheel when starting it up.
13. The face of the wheel must be flat and free from grooves.
14. Work should be feed slowly and gradually.
15. Make sure that the tool rest is only 1/8in from the face of the wheel.
16. Do not set tool rest while machine is in motion.
17. Use face of wheel only, unless it is designed for grinding on the side; otherwise,
side pressure may break the wheel. Use the entire face of the wheel to avoid
grooving.
18. Stop wheel if it chatters or vibrates excessively.
19. All wheels should be tested for soundness.
20. Hold the job against wheel firmly so that it will not slip out of the hand and cause
hands and fingers to come in contact to the wheel.
21. Use clamp or other holding devices for holding short pieces.
22. Always use face shield or goggles even of grinder is provided with protective
glass shields.

Sharpening Scriber and Center

Punch
1. Scriber and center punch
should be ground in the
position as shown beside.
2. Use the tool rest to rest your
hands while bringing the tool
in the right position.
3. Rotate the tool while grinding.
4. Cool the tool down from time
to time.
5. Do not overheat the metal.

Sharpening Chisel
1. Chisels should be ground in the position as
shown
2. Use the tool rest to rest your hands while
bringing the tool in the right position.
3. Use the whole grinding wheel while
grinding. Move with the tool regularly from
the left to the right side and back.
4. Cool the tool down from time to time.
5. Do not overheat the metal.
6. Grind the chisel−point parallel and straight.
Lathe Machine
 It is the forerunner of all the machine tools. The lathe is a machine tool used
principally for shaping pieces of metal (and sometimes wood or other materials) by
causing the workpiece to be held and rotated by the lathe while a tool bit is
advanced into the work causing the cutting action.

History
 Lathes were developed as early as the 15th century and were known as "bow"
lathes. The operator rotated the workpiece by drawing a bow back and forth, either
by hand or with the use of a foot treadle. Next became Bessons lathe in 1568, which
was driven by a cord passing over a pulley above the machine. This in turn drove
two other pulleys on the same shaft which rotated the workpiece and a crude,
wooden lead screw, which in turn allowed the operator to remove metal from the
piece being machined. The screw cutting lathe originates in the 17th century.
Development and advancements have continued and today we have sophisticated
computerized controlled lathes.
 The basic lathe that was designed to cut cylindrical metal stock has been developed
further to produce screw threads, tapered work, drilled holes, knurled surfaces, and
crankshafts. Modern lathes offer a variety of rotating speeds and a means to
manually and automatically move the cutting tool into the workpiece. Machinists and
maintenance shop personnel must be thoroughly familiar with the lathe and its
operations to accomplish the repair and fabrication of needed parts.
Sizes
 The size of an engine lathe is determined by the largest piece of stock that can be
machined. Before machining a workpiece, the following measurements must be
 considered: the diameter of the work that will swing over the bed and the length
between lathe centers.

Computer Numerical Control (CNC) Lathe Machine

 It is the general term used for a system which controls the functions of a machine
tool using coded instructions processed by a computer.
 It can be considered to be a means of operating a machine through the use of
discrete numerical values fed into the machine where the required input technical
information is stored on a kind of input media such as floppy disk, hard disk, CD
ROM, DVD, USB flash drive, or RAM card etc.
 In a simple word, a CNC is a system that receives numerical data, interpret the data
and then control the action accordingly.

CNC Applications
 The applications of CNC include both for machine tool as well as non-machine tool
areas.
 In the machine tool category, CNC is widely used for lathe, drill press, milling
machine, grinding unit, laser, sheet-metal press working machine, tube bending
 machine etc. Highly automated machine tools such as turning center and machining
center which change the cutting tools automatically under CNC control have been
developed.
 In the non-machine tool category, CNC applications include welding machines (arc
and resistance), coordinate measuring machine, electronic assembly, tape laying
and filament winding machines for composites etc.
Advantages of CNC
 Higher flexibility: This is essentially because of programmability, programmed control
and facilities for multiple operations in one machining centre,
 Increased productivity: Due to low cycle time achieved through higher material
removal rates and low set up times achieved by faster tool positioning, changing,
automated material handling etc.
 Improved quality: Due to accurate part dimensions and excellent surface finish that
can be achieved due to precision motion control and improved thermal control by
automatic control of coolant flow.
 Reduced scrap rate: Use of Part programs that are developed using optimization
procedures
 Reliable and Safe operation: Advanced engineering practices for design and
manufacturing, automated monitoring, improved maintenance and low human
interaction.
 Smaller footprint: Due to the fact that several machines are fused into one.
Disadvantages
 Relatively higher cost compared to manual versions
 More complicated maintenance due to the complex nature of the technologies
 Need for skilled part programmers.
The above disadvantages indicate that CNC machines can be gainfully deployed only
when the required product quality and average volume of production demand it.
HEADSTOCK AND FEED MECHANISM

4 7

1 9

10

1. Motor switch
2. Isolating switch
3. Gear box
4. Feed reversing lever
5. Clutch
6. Speed selector
7. Spindle nose
8. Lead screw
9. Feed rod
10. Feed selector
TAILSTOCK

4
3

2
5

1. Spindle bore
2. Tailstock spindle
3. Spindle clamp
4. Body clamp
5. Tailstock hand wheel
6. Upper and lower casting clamp
7. Adjusting screw
BED WAYS

2 3
1
4

1. Vee ways
2. Rib casting
3. Heavy construction
4. Flat ways

CARRIAGE 3
2
9

1 7

6
5
8
4
1. Tool post
2. Compound rest
3. Cross slide
4. Micrometer collars
5. Carriage clamp
6. Carriage hand wheel
7. Feed selector
8. Feed control
9. Half nut lever
TYPES OF LATHES

Bench Lathe

 A small lathe usually mounted on a bench and is used for small works. They
have usually made up of all attachments that the large lathe have.

Engine Lathe

 It is large than the bench lathe and it is a machine tool on which many lathe
operations are done like facing, turning, threading, boring, etc.
Turret Lathe

 A special lathe designed to perform a number of operations on a single work

piece. It is characterized by a tool mounting turret. The turret is usually
hexagonal and is designed to hold a variety of cutting tools. Each tool may be
brought into an operative position by rotating the turret.

Top View of Turret Lathe

Turret Lathe/ Front View

HOW TO DISTINGUISH BETWEEN RIGHT AND LEFT HAND TOOLS

Left Hand Right Hand

Headstock
operator Tailstock
facing the
lathe

1 2
3 4 6 7
5

When the tool is held face up with the nose pointing away from the operator and
the cutting edge is on the right side, it is considered a LEFT – HAND TOOL because it
is used to make a cut that begins on the operators left even though it moves to his right;
and vice versa, if the cutting edge of the tool is on the left side, it is called a RIGHT –
HAND TOOL.

1. Left hand roughing tool

2. Left hand turning tool
3. Left hand facing tool
4. Round nose turning tool
5. Right hand facing tool
6. Right hand turning tool
7. Right hand roughing tool
LATHE CUTTING TOOLS

A. Typical outside turning tools

B. Typical boring and facing tools

C. Thread cutting tools

Lathe cutting tools are made of:

A. High speed steel

B. Carbide (throws away and cemented)
C. Ceramics
D. Diamond
TO GRIND A GENERAL PURPOSE TOOL BIT

1. Dress the face of the grinding wheel.

2. Grip the tool bit firmly, supporting the hands on the grinder tool rest.
3. Hold the tool bit at the proper angle to grind the cutting edge angle. At the same
time, tilt the bottom of the tool bit in toward the wheel and grind the 10 side relief
or clearance angle on the cutting edge.

NOTE: The cutting edge should be approximately ½’’ (13mm) long and should
extend over about one – quarter the width of the tool bit.

4. When grinding, move the tool bit back and forth across the face of the wheel.
This accelerates grinding and prevents grooving the wheel.
5. The tool bit must be cooled frequently during the grinding operation. Never
overheat a tool bit.

NOTE: Never quench cemented carbide tools and never grind carbides with
aluminium oxide wheel.

6. Grind the end cutting edge so that it forms an angle of a little less than 90 with
the side cutting edge. Hold the tool so that the end cutting edge angle and end
relief angle of 15 are ground at the same time.

7. Check the amount of end relief when the tool bit is in the tool bit holder using a
tool bit grinding gage.

8. Hold the top of the tool bit at approximately 45 to the axis of the wheel and grind
the side rake to approximately 14.
9. Grind slight radius on the point of the cutting tool, being sure to maintain the
same front and side clearance angle.
10. With an oilstone, hone of the cutting edge of the tool bit slightly. This will lengthen
the life of the tool bit and enable it to produce a better surface finish.
CUTTING TOOL EFFICIENCY

A machine tool is no more efficient than its cutting tool. Magnesium alloys call for
tools od somewhat different design from those used on iron or copper alloys, while cast
iron calls for tool of different design from those use on the alloy steel.

Cutting tools must combined sufficient strength to maintain a sharp cutting edge,
sufficient wear resistance to prevent wearing of the cutting edge, sufficient toughness to
prevent chipping of the cutting edge, and sufficient hardness to prevent picking up of the
chips.

Five necessary points to be observed:

1. The right kind of tool material for the purpose of the tool must be selected.
2. The tool must be given the correct hardening and heat treatment.
3. The tool must be correctly designed.
4. The tool must be accurately be made by the tool maker.
5. The tool must be properly applied in the machining operation with the proper
coolant and lubricant.

The action of the cutting tool depends primarily on three things:

1. The rigidity of the work that is, of the piece itself, and the manner in which it is
held in the machine.
2. The rigidity of the tool, its size and the way in which it is held.
3. The shape of the cutting tool as it is ground, and as it is presented to the work.

It is very necessary for the student in machine shop practice to realize in the
beginning that the cutting tool is the most important factor. There is nothing in shop
work that would be given more thoughtful consideration than cutting tools.

NOTE: Time is always wasted if an improperly shaped tool is used.

TYPES OF SHOULDERS

Left – Hand Right - Hand

Facing Tool

Round - Nose

A. SQUARE B. FILLETED C. TAPERED

When turning more than one diameter on a piece of work, the change in diameter
or step is known as SHOULDER.

TYPES OF GROOVES

A. SQUARE B. ROUND C. V – SHAPED

GROOVING, commonly called recessing, under – cutting or necking is often

done at the end of a thread or permit full travel of the nut up to a shoulder or at the edge
of a shoulder to ensure a proper fit of mating parts.
 4
7
6
2 3 5 8 9
1
5
B
A

RH R H Tool

LH L H Tool

1. Threaded
2. Parted
3. Turned
4. Faced
5. Necked
6. Tapered
7. Knurled
8. Radius formed
9. Bevelled

This illustration establishes the terms that apply to various lathe operations
performed on different surfaces of a work piece. It also shows the character of tools
used and the direction of tool movement.

NOTE: A. External thread (sharp V – thread)

B. Internal thread
Cutting speed (CS)

 It may be defined as the rate at which a point on the work circumference

travels fast the cutting tool. Cutting speed is always expressed in
Industry demands that machining operations be performed as quickly as
possible; therefore, correct cutting speed must be used for the type of
material being cut.

Feed

 It may be defined as the distance the cutting tool advances along the length
of the work for every revolution of the spindle. For example, if the lathe is set
for a 0.015in (0.40mm) feed, the cutting tool will travel along the length of the
work 0.015in (0.40mm) for every complete turn that the work makes.

Depth off cut

 It may be defined as the depth of the chip taken by the cutting tool and is one
– half the total amount removed from the work piece in one cut. When
machining a work piece, take only one roughing and one finishing cut if
possible. The depth of a rough turning cut will depend on the following
factors:
1. The condition of the machine
2. The type and shape of the cutting tool used
3. The rigidity of the work piece, the machine and the cutting tool
4. The rate of feed
 The depth of a finish turning cut will depend on the type of work and the finish
required. In any case, it should not be less than 0.005in (0.13mm).

NOTE: In order to operate a lathe efficiently, the machinist must consider the
importance of cutting speed, feed and depth of cut.
RECOMMENDED CUTTING SPEED

TURNING AND BORING

ROUGH CUT FINISH CUT THREADING
MATERIALS Ft/min m/min Ft/min m/min Ft/min m/min
Machine steel 90 27 100 30 35 11
Tool steel 70 21 90 27 30 9
Cast iron 60 18 80 24 25 8
Bronze 90 27 100 30 25 8
Aluminum 200 61 300 93 60 18
NOTE: For high – speed cutting tool only.

RECOMMENDED FEED

ROUGH CUT FINISH CUT

MATERIALS In mm in mm
Machine steel 0.010 – 0.020 0.25 – 0.50 0.003 – 0.010 0.07 – 0.25
Tool steel 0.010 – 0.020 0.25 – 0.50 0.003 – 0.010 0.07 – 0.25
Cast iron 0.015 – 0.025 0.40 – 0.65 0.005 – 0.012 0.13 – 0.30
Bronze 0.015 – 0.025 0.40 – 0.65 0.003 – 0.010 0.07 – 0.30
Aluminum 0.015 – 0.030 0.40 – 0.75 0.005 – 0.010 0.13 – 0.25
NOTE: For high – speed steel cutting tool only.

CALCULATIONS/ FORMULAS

ENGLISH SYSTEM METRIC SYSTEM

____________________

____________________

 Distance – length of cut

 CS – cutting speed
 D – Diameter
 RPM – rev. per minute
 LATHE ACCESSORIES AND ATTACHMENTS

Lathe Accessories

 These are tools used to hold the cutting tool and to rotate the work piece.

Lathe Attachments

 These are devices that mounted on the lathe so that a wider range of operations
may be performed.

COMMON LATHE ACCESSORIES

Lathe Dog

 It is a device used with the drive plate as a simple means of causing the work
piece to rotate with the live center when the work is mounted between centers.

COMMON TYPES OF LATHE DOGS

Bent tail lathe dog with headless screw Bent tail lathe dog with square head screw

Bent tail clamp type lathe dog Safety clamp Straight tail
Lathe Tool Holders

 It is a devise used in holding cutting tools/ tool bits when turning in a lathe.

COMMON LATHE TOOL HOLDERS

Left – hand offset Right – hand offset

Carbide inserts Straight tool holder

Carbide tool holder Thread cutting

Boring tool bits and

holders
Lathe Centers

 Lathe centers are the most common devices for supporting workpieces in the
lathe.

Dead Center

Ball Center

Half Center

Revolving Center
Mandrel

 A mandrel is a tapered axle pressed into the bore of the workpiece to support it
between centers.

Straight Solid Mandrel

Gang Mandrel

Threaded Mandrel

Taper – Shank Mandrel

Expansion Mandrel
 COMMON LATHE ATTACHMENTS

Face plates

 A lathe faceplate is a flat, round plate that threads to the headstock spindle of the
lathe. The faceplate is used for irregularly shaped workpieces that cannot be
successfully held by chucks or mounted between centers. The workpiece is
either attached to the faceplate using angle plates or brackets or bolted directly
to the plate. Radial T-slots in the faceplate surface facilitate mounting
workpieces. The faceplate is valuable for mounting workpieces in which an
eccentric hole or projection is to be machined.

Drive plates

 A small faceplate known as a driving faceplate/ drive plate is used to drive the
lathe dog for workpieces mounted between centers. The driving faceplate usually
has fewer T-slots than the larger faceplates. When the workpiece is supported
between centers, a lathe dog is fastened to the workpiece and engaged in a slot
of the driving faceplate.

NOTE: The number of applications of the faceplates depends upon the ingenuity
of the machinist.

Face plate

Drive plate
Lathe Chuck

 A lathe chuck combines the features of the independent chuck and the universal
scroll chuck and can have either three or four jaws. The jaws can be moved in
unison on a scroll for automatic centering or can be moved individually if desired
by separate adjusting screws.

Three Jaw Chuck/ Universal Chuck

 The universal scroll chuck usually has three jaws which move in unison as an
adjusting pinion is rotated. The advantage of the universal scroll chuck is its ease
of operation in centering work for concentric turning. This chuck is not as
accurate as the independent chuck, but when in good condition it will center work
within 0.002 to 0.003 inches of run out.

Four Jaw Chuck/ Independent Chuck

 The independent chuck generally has four jaws which are adjusted individually
on the chuck face by means of adjusting screws. The chuck face is scribed with
concentric circles which are used for rough alignment of the jaws when chucking
round workpieces. The final adjustment is made by turning the workpiece slowly
by hand and using a dial indicator to determine its concentricity. The jaws are
then readjusted as necessary to align the workpiece within the desired
tolerances.
 The jaws of the independent chuck may be reversed so that the steps face in the
opposite direction; thus workpieces can be gripped either externally or internally.

Universal chuck Independent chuck

Drill Chuck

 A gripping device with two or more adjustable jaws set radially. It is made
especially for holding straight shank twist drill, reamers and other cutting tools
in the spindle of the machine and it is provided with a taper shank which fits
the taper hole in the tailstock spindle.

Drill Holder

 A device used in driving a large twist drill which holds the drill outside of the
tailstock lathe spindle. It is placed on the shank of the tool holder and against
the back of the tool post. The taper shank of the twist drill fits into the
matching taper inside the drill holder which is supported by a tailstock center.

Drill Chuck

Collet Chuck Attachment

 The collet chuck is the most accurate means of holding small workpieces in
the lathe. The collet chuck consists of a spring machine collet and a collet
attachment which secures and regulates the collet on the headstock spindle
of the lathe.

Square Collet Hexagonal Collet Round Collet Cut – away view

  The spring machine collet is a thin metal bushing with an accurately machined
bore and a tapered exterior. The collet attachment consists of a collet sleeve, a
drawbar, and a handwheel or hand lever to move the drawbar.

Spring machine collet

Steady Rest

 The steady rest, also called a center rest is used to support long workpieces for
turning and boring operations. It is also used for internal threading operations
where the workpiece projects a considerable distance from the chuck or
faceplate.

Steady Rest

Cathead

 When the work is too small to machine a bearing surface for the adjustable jaws
to hold, then a cathead should be used. The cathead has a bearing surface, a
hole through which the work extends, and adjusting screws.

Cat Head
Follower Rest

 The follower rest has one or two jaws that bear against the workpiece. The rest is
fastened to the lathe carriage so that it will follow the tool bit and bear upon the
portion of the workpiece that has just been turned.

Follower Rest

Micrometer Carriage Stop

 The micrometer carriage stop is used to accurately position the lathe carriage.
The micrometer stop is designed so the carriage can be moved into position
against the retractable spindle of the stop and locked into place.

Micrometer Carriage Stop

Tool Post Grinder

 The tool post grinder is a machine tool attachment specially designed for
cylindrical grinding operations on the lathe. It consists primarily of a 1/4-or 1/3-
horsepower electric motor and a wheel spindle connected by pulleys and a belt.

Tool Post Grinder

Taper Attachment

The taper attachment has many features of special value, among which are the
following:

 The lathe centers remain in alignment and the center holes in the work are not
distorted.
 The alignment of the lathe need not be disturbed, thus saving considerable time
and effort.
 Taper boring can be accomplished as easily as taper turning.
 A much wider range is possible than by the offset method. For example, to
machine a 3/4-inch-per-foot taper on the end of a bar 4 feet long would require
an offset of 1 1/2 inches, which is beyond the capabilities of a regular lathe but
can be accomplished by use of the taper attachment.

Taper Attachment Taper Turning and Boring

Tool Posts

 Standard tool holders for high-speed steel cutting tools have a square slot made
to fit a standard size tool bit shank.

Standard Round Tool Post

 CENTERING

 It is the process of aligning the work axis along the axis of the lathe main spindle.
Carefully attention is given when performing this process because of the
accuracy of the work piece.
 Different shapes of work pieces are machined in the lathe. The most common
are circulars and sometimes hexagonal, square and rectangular.

Surface gage/ Scriber

 It is a centering device that determines whether the work piece is chucked

accurately. It is efficient when moderate degree of mounting is required.

Surface gage/ Scriber

Dial indicator

 It is specifically test set. It is a general purpose gage used in many testing work
in machine shop, but it is common used for setting or centering work piece of
work accurately in a four jaw lathe chuck.

Dial Indicator
METHODS OF CENTERING

A. Chalk method
 It is an alternative method of centering a work piece in a lathe and it is a
simple way in checking work piece. The work piece is rotated slowly and a
fixed of chalk held in a fixed position is brought in contact with the rotating
surface. If not mount properly in the chuck, only the high side will be mark.

B. Surface gage/ Scriber method

 It determines whether a work
piece is chucked accurately.
It is efficient when moderate
degree of mounting is
required. The scriber can be
place at the end of the work
piece or on the surface.

C. Dial indicator method

 It is an accurate method of centering work piece. It is used when a high
degree of accuracy is required.
1. Adjust the center point of the
indicator on the work piece with
at least one complete
revolution.
2. Adjust the pointer of the dial to
zero.
3. Rotate the work piece by the
hand and determine the extent
to which is not properly in
center.
4. Stop the work piece at the point of highest dial reading; then move it in
a direction from this point toward its center.
 D. Using a Wiggler
 This method of centering is uses especially
when the workpiece has irregular shaped and
aid out of center point. It is usually
accomplished with a dial indicator for more
accurate set – up.

E. Centering an Irregular Shaped Workpiece

 It uses the concentric rings on the face of the chuck as guide. For more
accurate set – up, surface gage or dial indicator can be used.

CENTERING

Checking the alignment of the lathe centers

Drilling the center hole in the end of a shaft

Work mounted between centers

A correctly drilled and countersunk hole

SETTING THE TOOL

1. Catch the tool short. The further the cutting edge of any tool projects from the
tool post, the greater leverage and the more the spring of the tool. This cause
chattering and often worse evils and should be avoided wherever possible.

2. The tool post should be located at the left – hand end of the T – slot in the tool
rest/ post. It is clamped in the middle or right – hand end of the slot. The danger
of the dog/ chuck hitting the tool rest is greatly increased. If the dog/ chuck hit the
tool rest when the lathe is running, the point of the live center will be broken off
and the center hole in the work spoiled.

3. The position of the cutting edge as presented to the work has a considerable
influence on the finished appearance of the work and also on the life of the tool. It
may be easily proved that a cutting edge at right angles to the center line of the
work will not cut so efficiently as when arranged at an angle of about 20 with this
perpendicular.

A. Most efficient turning tool

B. Does not remain sharp as long or procedure as good work as A.
C. Inefficient except for some finishing cuts
4. The usual practice with modern lathe turning tools (tool holders with high speed
tool bits) is to set the tool point toward the dog, thus obtaining approximately the
proper side rake with less grinding on the top of the tool bit. This is all right for
light cuts if care is taken to tighten the tool securely in the tool post.

o For heavy cuts, however, it is best if possible to have the tool point a
little away from the work and not into it.

5. Have the point of the tool on center in order to have the correct amount of front
clearance.

Setting up of the cutting tool

 CENTER DRILLING OPERATION

Center drilling

 It is a process of producing a center hole in solid metal by drilling and

countersinking hole in each end of the work piece.

Drill Point

Body Size
Center Drill

Center drilling in a lathe with work held in a chuck

Types of center drill

1. Plain type combination center drill

2. Bell type combination center drill

Three commonly used methods on center drilling

1. With a drill press

2. With the work piece in a lathe chuck
3. With the work piece between centers

Insert the center drill into the drill chuck

with not more than 12mm protruding
beyond the chuck jaws.
 Set the tailstock spindle until extends
approximately 25mm beyond the tailstock.

Drill hole until approximately three

quarters of the tapered portion of the
center drill.

Common sizes for combination

countersunk and counter drill

TURNING TOOLS

 Turning tools have a single cutting edge. They are used for forming materials by
chip removal. The basic shape of the cutting edge of a turning tool is a wedge
(chisel – shaped). The cutting head of turning tools are usually of high – speed
tool steel.
 The cutting action is affected by the motion of the work piece (main motion) and
the tool feed motion. The forces generated by the cutting action act on the tool
and the machine. The force on the turning tool can be resolved as follows:
1. Main cutting force
2. Transverse force
3. Feed force
 STRAIGHT TURNING

 It is the process of producing a cylindrical piece of work on which the diameter is

uniform in size throughout its entire length.
 It is the process of reducing the work diameter to a specific dimension as the
carriage moves the tool along the work.
 The work is machined on a plane parallel to its axis so that there is no variation in
the work diameter throughout the length of the cut.

Principles of lathe turning

Turning workpiece between centers Turning workpiece held in a chuck

Checking the alignment of the points of the lathe centers

SHOULDER TURNING

 It is an operation of turning two or more diameters cut on a work piece. The

shoulder is formed at the point where the size changes from one diameter to
another.
Types of shoulder

A. Square shoulders
 It is used on work that is not subject to excessive strain at
the corners. This shape provides a flat clamping surface and
permits parts to be fitted squarely together.

B. Filleted shoulders
 Its corners are rounded and to be used on parts which
require additional strength at the shoulder. These shoulders
are machined with a round-nose tool bit or a specially
formed tool bit.

C. Bevelled/ Angular shoulders

 Although not as common as filleted shoulders, are
sometimes used to give additional strength to corners, to
eliminate sharp corners, and to add to the appearance of the
work.

Turning workpiece (pulley) mounted

on a mandrel

TURNING CLASSIFICATION

Rough turning

 It is an operation of removing excess materials as

quickly as possible to the required diameter and to
prepare the work piece for finish turning. Rough turning
requires a deep cut as possible, a coarse feed and a
speed that is consistent with good safety practices.

Finish turning

 It is an operation of machining a work piece to the

required dimension within the tolerance specified.
Finish turning generally requires a light cut and a faster
speed and finer feed than used for rough turning. The
cutting tool should be sharp and of a suitable form or
shaped to produce a smooth cut.
 COMMON ERRORS IN CENTER DRILLING

CONDITION OF ERROR HOW TO AVOID AND

CENTERHOLE CORRECT THE ERROR
 No clearance for point  Drill pilot hole
of center  Countersink pilot hole
 Center hole incomplete at 60
 Insufficient bearing  Drill center hole with
surface for lathe center center drill

 No bearing surface for  Counter mouth of hole

center at 60

 Insufficient bearing  Countersink deeper

surface for lathe
centers

 Holed drill too deep  Face the end of the

with center drill workpiece
 Poor bearing surface  Ream mouth with
center reamer

 Poor bearing surface  Countersink hole with

 Wrong angle 60 center drill

 Center drilled at angle  Align work squarely

to the axis of the when drilling center
workpiece hole
 Face end and re-center
 FACING

 Facing is machining the ends and shoulders of a piece of stock smooth, flat, and
perpendicular to the lathe axis. Facing is used to cut work to the desired length
and to produce a surface from which accurate measurements may be taken.

Positioning tool bit for facing

FACING WORK PIECE HELD IN A CHUCK WITH THE COMPOUND REST AT 90

 A series of steps or shoulders can be

accurately spaced and along the length
of the work piece when the compound
rest is set at 90 to the cross slide. The
amount of the tool bit travel is the same
as the reading on the graduated collar
of the top slide.

FACING WORK MOUNTED BETWEEN CENTERS

Facing using a side finishing tool and a half center

 Sometimes the workpiece will not fit into

a chuck or collet, so facing must be
done between centers. To properly
accomplish facing between centers, the
workpiece must be center-drilled before
mounting into the lathe.
FACING WORK PIECE HELD IN A CHUCK WITH THE COMPOUND REST AT 90

Procedure

1. Swivel the compound rest at 30.

2. Insert the facing tool in the tool holder
allowing it to extend only about 12mm.
3. Set the facing tool to the center of the
work.
4. Bring the tool bit close to the center of
the surface to be faced.
5. Lock the carriage to prevent it from
moving during a cut.
6. Feed the top slide screw in until a light
cut is started.
7. Stop the lathe.
8. Set the feed dial to zero.
9. Measure the work and calculate the
amount of material to be removed.
10. Start the lathe. Advance the feed by a
small amount and again face the work
until it reached the exact measurement.

NOTE: When compound rest is set at 30, the amount of side movement of the
cutting tool, (example is parallel movement to the axis of the work) is
always ½ of the feed distance indicated of the calibrated hand wheel.
 KNURLING

 It is a process of impressing a diamond – shaped or straight line pattern into the

surface of the work piece to improve its appearance or to provide a better
gripping surface.

 Straight knurling is often used to increase the workpiece diameter when a press
fit is required between two parts.

Knurls Classification

Knurling Tool

Single head Revolving head

To Knurl in a Lathe

1. Mount the work between centers and mark the required length to be knurled.
If the work is held in a chuck for knurling, the right end of the work should be
supported with a revolving tailstock center.
2. Set the lathe to run at one – quarter the speed required for turning.
3. Set the center of the floating head of the knurling tool even with the dead –
center point.
4. Set the knurling tools at right angles to the workpiece and tighten it securely.

 The knurling tool set at 90

and moves near the end of
the workpiece
 5. Start the machine and lightly touch the rolls against the work to make sure
that they are trucking properly. Adjust if necessary.

Correct pattern

6. Move the knurling tool to the end of the work so that only half the roll faces
bears against the work. If the knurl does not extend to the end of the
workpiece, set the knurling tool at the correct limit of the section to be knurled.
7. Force the knurling into the work approximately 0.025” (0.63mm) and start the
lathe or start the lathe and then force the knurling tool into the work until the
diamond patterns comes to a point.
8. Stop the lathe and examine the pattern. If necessary, reset the knurling tool.

Incorrect pattern

a. If the pattern is incorrect, it is usually the knurling tool is not set on center.
b. If the knurling tool is on center and the pattern is not correct, it is generally
due to worn knurling rolls. In this case, it will be necessary to set the knurling
tool off square slightly so that the corner of the knurling rolls can start the
pattern.

9. Once the pattern is correct, engage the automatic carriage feed and apply
cutting fluid to the knurling rolls.
10. Knurl to the proper length and depth.
11. If the knurling pattern is not to a point after the length has been knurled,
reverse the lathe feed and take another pass across the work.

Damaged (ring)

NOTE: Do not disengage the feed until the full length has been knurled;
otherwise, rings will be formed on the knurled pattern.
 THREAD CUTTING

To set up a lathe for threading (60 Thread)

1. Set the lathe speed to about one – quarter the speed used for turning

2. Set the quick change gear box for the required pitch in thread per inch or
in millimeter

3. Engage the lead screw

4. Secure a 60 threading tool bit and check the angle using a thread center
gage

5. Set the compound rest at 29 to the right; see it to the left for a left hand
thread

NOTE: The threading tool is fed in with the compound rest handle

6. Set the cutting tool to the height of the lathe canter point

7. Mount the work between centers. Make sure the lathe dog is tight on to
the work. If work is mounted on a chuck, it must be held tightly

8. Set the tool bit at right angle to the work, using a thread center gage

9. Arrange the apron controls to allow the split – nut lever to be engaged.
THREAD CUTTING OPERATION

 Thread cutting is one of the special operations in machining which can be

performed on a lathe. It involves manipulation of the lathe parts, coordination of
the hands and strict attention to the operation.

To cut a 60 thread

1. Check the major diameter of the work for size. It is good practice to have a
diameter of 0.002in (0.05mm) undersize

2. Start the lathe and chamfer the end of the workpiece with the side of the
threading tool to just below the minor diameter of the thread

3. Mark the length to be threaded by cutting a light groove the point with the
threading tool while the lathe is revolving

4. Move the carriage until the point of the threading tool is near the right end of
the work.

5. Turn the cross feed handle until the threading tool is close to the diameter,
but stop when the handle is at 3 o’clock position

6. Hold the cross feed handle in this position and set the graduated collar to
zero

7. Turn the compound rest handle until the threading tool lightly marks the work

8. Move the carriage to the right until the tool bit clears the end of the work

9. Feed the compound rest clockwise about 0.003in (0.08mm)

10. Engage the split – nut lever on the correct line of the thread chasing dial and
take a trial cut along the required length to be threaded

11. At the end of the cut, turn the cross feed handle counter clockwise to move
the tool bit away from the work and then disengaged the split – nut lever. In
other lathe machines, the half – nut lever is not being disengaged until the
required cut is attained. Only the reverse/ forward switch is being manipulated
 12. Stop the lathe and check the number of TPI with a thread pitch gage, rule or
center gage. If the pitch produced by a trial cut is not correct, recheck the
quick gear box setting

13. After each cut, turn the carriage handwheel to bring the tool bit to the start of
the thread and return the cross feed handle to zero

14. Set the depth of all threading cuts with the compound rest handle

NOTE: When the tool is fed in at 29, most of the cutting is done by the leading
edge of the tool bit

15. Apply cutting fluid and take successive cuts until the top (crest) and the
bottom (root) of the thread are in the same width

16. Remove the burs from the top of the thread with a file

17. Check the thread until the required pitch is attained

Six ways of checking thread pitch

1. Master nut
2. Thread micrometer
3. Thread roll or snap gage
4. Three wires
5. Thread ring or plug gages
6. Optical comparator
 INTERNAL THREADS

1. Calculate tap drill size of the thread

Example: to cut 1 3/8” – 6NC internal thread

Tap drill size = major diameter – 1/N

TDS = 1.375 – 1/6 TDS = 1.375 – 0.116 TDS = 1.209”

2. Mount the work to be threaded in a chuck or a collet

3. Drill a hole approximately 1/16inch smaller than the trap drill size in the
workpiece. For this thread, it would be 1.209 – 0.062 = 1.147 or 1 5/32inch
hole

4. Mount a boring tool in the lathe and bore the hole to the tap drill size
(1.209in). The boring bar should be as large as possible and held short in the
tool post. The boring operations cut the whole size and make its diameter to
its required size.

5. Recess the start of the hole to major diameter of the thread for 1/16” length.
During the thread cutting operation, this will indicate when the thread is cut to
depth.

6. If the thread does not go through the workpiece, a recess should be cut at the
end of the thread to the major diameter. This recess should be wide enough
to allow the threading tool to run out and permit time to disengage the split –
nut lever.

NOTE: The compound rest is set at 29 to the left for cutting right – hand thread

7. Set the compound rest 29 to the left for cutting right – hand thread and right
for left – hand thread
 8. Mount a threading tool bit into the boring bar and set it to the center

9. Set the threading tool using a thread center gage

10. Put a mark on the boring bar to indicate the length that is to be threaded. The
marking will also shows when to retract the threading tool

11. Start the lathe and turn the cross feed handle out until the threading tool just
scratches the internal diameter

12. Set the cross feed graduated collar to zero

13. Set a 0.003in depth of cut the feeding the compound rest out and take a trial
cut

14. At the end of each cut on the internal thread, disengage the half – nut lever
and turn the cross feed handle in to clear the thread

15. Clear the threading tool from the hole and check the pitch of the thread

16. Return the cross feed handle back to zero and set the depth of cut by turning
the compound rest out to the desired amount

17. Cut the thread to the required depth and check the pitch using a screw or
threaded plug gage

NOTE: The last few cuts should not be deeper than 0.001”
 THREADS

 A thread may be defined as a helical ridge of uniform section formed on the

inside or outside of a cylinder or cone.

 Threads are used for several purposes such as the following:

 To fasten devices such as screws, bolts and nuts

 To provide accurate measurement as in a micrometer

 To transmit motion; the threaded lead screw on the lathe causes the
carriage to move along when threading

 To increase force; heavy work can be raised with a screw jack

Parts of a screw thread

Screw Thread Terminology

The common terms and definitions below are used in screw thread work and will be
used in discussing threads and thread cutting.
 External or male thread is a thread on the outside of a cylinder or cone.
 Internal or female thread is a thread on the inside of a hollow cylinder or bore.
 Pitch is the distance from a given point on one thread to a similar point on a
thread next to it, measured parallel to the axis of the cylinder. The pitch in inches
is equal to one divided by the number of threads per inch.
 Lead is the distance a screw thread advances axially in one complete revolution.
On a single-thread screw, the lead is equal to the pitch. On a double-thread
screw, the lead is equal to twice the pitch, and on a triple-thread screw, the lead
is equal to three times the pitch.
  Crest (also called "flat") is the top or outer surface of the thread joining the two
sides.
 Root is the bottom or inner surface joining the sides of two adjacent threads.
 Side is the surface which connects the crest and the root (also called the flank).
 Angle of the thread is the angle formed by the intersection of the two sides of the
threaded groove.
 Depth is the distance between the crest and root of a thread, measured
perpendicular to the axis.
 Major diameter is the largest diameter of a screw thread.
 Minor diameter is the smallest diameter of a screw thread.
 Pitch diameter is the diameter of an imaginary cylinder formed where the width of
the groove is equal to one-half of the pitch. This is the critical dimension of
threading as the fit of the thread is determined by the pitch diameter (Not used
for metric threads).
 Threads per inch are the number of threads per inch may be counted by placing
a rule against the threaded parts and counting the number of pitches in 1 inch. A
second method is to use the screw pitch gage. This method is especially suitable
for checking the finer pitches of screw threads.
 A single thread is a thread made by cutting one single groove around a rod or
inside a hole. Most hardware made, such as nuts and bolts, has single threads.
Double threads have two grooves cut around the cylinder. There can be two,
three, or four threads cut around the outside or inside of a cylinder. These types
of special threads are sometimes called multiple threads.
 A right-hand thread is a thread in which the bolt or nut must be turned to the right
(clockwise) to tighten.
 A left hand thread is a thread in which the bolt or nut must turn to the left (counter
clockwise) to tighten.
 Thread fit is the way a bolt and nut fit together as to being too loose or too tight.
 Metric threads are threads that are measured in metric measurement instead of
inch measurement.

Screw thread types

Common gages for checking threading tool bits

Thread forms
 DRILLING OPERATIONS

Lathe chuck

Workpiece

Drill chuck

Drill

1. To start the drilling operation, compute the correct RPM for the drill and set the
spindle speed accordingly.
2. Ensure the tailstock is clamped down on the lathe ways.
3. The feed is controlled by turning the tailstock handwheel. The graduations on the
tailstock spindle are used to determine the depth of cut.
4. If a large twist drill is used, it should be preceded by a pilot drill, the diameter of
which should be wider than the larger drills web.
5. Use a suitable cutting fluid while drilling. Always withdraw the drill and brush out
the chips before attempting to check the depth of the hole.
6. If the drill is wobbling and wiggling in the hole, use a tool holder turned
backwards to steady the drill.

7. Always use a drill that is properly ground for the material to be drilled.
8. Use care when feeding the drill into the work to avoid breaking the drill off in the
work.
9. The drill should never be removed from the work while the spindle is turning
because the drill could be pulled off the tailstock spindle and cause injury or
damage.
TAPER TURNING

 When the diameter of a piece changes uniformly from one end to the other, the
piece is said to be tapered.

 Taper turning as a machining operation is the gradual reduction in diameter from

one part of a cylindrical workpiece to another part.

 Tapers can be either external or internal. If a workpiece is tapered on the outside,

it has an external taper; if it is tapered on the inside, it has an internal taper.

Three basic methods of turning tapers with a lathe

1. With the use of the compound rest

2. Offset the tailstock

3. With the use of taper attachment

Compound Rests

 The compound rest is favorable for turning or boring short, steep tapers, but it
can also be used for longer, gradual tapers providing the length of taper does not
exceed the distance the compound rest will move upon its slide.

 This method can be used with a high degree of accuracy, but is somewhat
limited due to lack of automatic feed and the length of taper being restricted to
the movement of the slide.

 The compound rest base is graduated in degrees and can be set at the required
angle for taper turning or boring. With this method, it is necessary to know the
included angle of the taper to be machined.

 The angle of the taper with the centerline is one-half the included angle and will
be the angle the compound rest is set for. For example, to true up a lathe center
which has an included angle of 60°, the compound rest would be set at 30° from
parallel to the ways.

 If there is no degree of angle given for a particular job, then calculate the
compound rest setting by finding the taper per inch, and then calculating the
tangent of the angle (which is the: compound rest setting).

Formula:

Where:

TPI = taper per inch

D = large diameter,
d = small diameter,
L = length of taper
angle = compound rest setting

Checking tapers using plug gage

 SHAPER

 A shaper is a machine tool which holds and locates a workpiece on a table and
machines or cuts the workpiece by feeding it against a reciprocating cutting tool.
 In other words, the ram of the shaper moves a single point cutting tool back-and-
forth, and on each forward stroke, the tool removes a chip of metal from the
workpiece. The workpiece is held in the vise of the shaper or secured to the table
of the shaper with clamps, T-bolts, etc.
 When horizontal surfaces are being machined, the table automatically feeds the
work to the cutting tool on each return stroke of the ram.
 When vertical cuts are being made, the work is fed to the cutting tool on each
return stroke of the ram either manually or automatically.
 The cutting tool on a shaper can be set to cut horizontally, on an angle, or
vertically.
 Shaper size is determined by the largest cube which can be machined on the
shaper. A 14" shaper can machine a cube 14" x 14" x 14"; a 300 mm shaper can
machine a cube 300 mm x 300 mm x 300 mm, and so forth.
TYPES OF SHAPERS

There are three types of shapers:

Crank shapers

 Crank shapers are most commonly used. A rocker arm, operated by a crank pin
from the main driving gear, gives the ram of the crank shaper a back-and-forth
(reciprocating) motion.

Gear shapers

 Gear shapers are driven by a gear and rack assembly. Gear shapers have a
reversible electric motor or mechanical mechanism which quickly returns the
ram, in readiness for another cut.

Hydraulic shapers

 Hydraulic shapers are driven by movement of a piston in an oil-filled cylinder.

Mechanical features on these shapers are the same as those on crank shapers.

PARTS OF A SHAPER
 The base and column provide the main support and structure for the machine
 The ram provides the back – and – forth strokes or forward and return motion for
the cutting tool
 Stroke indicator shows the length of stroke
 Stroke regulator shaft adjust the length of stroke
 Stroke regulator nut locked in place the stroke regulator shaft
 Ram adjusting shaft is use to set the position of the stroke
 Ram positioning lock locked in place the ram adjusting shaft
 Table is fastened to the crossrail
 Cross rail provides support for the work
 Vertical traverse shaft can lower or raises the table
 Cross feed traverse crank moves the table horizontally under the cutting tool
 Cross feed direction lever automatically feeds the table and workpiece to the
cutting tool when cutting horizontally
 Gear change levers can set the several speeds that is required to the needed
work
 Tool head is fastened to the ram

Tool head

 Apron is attached to the tool head and is hooked over the rail and moves right
and left to the rail (apron consists of a clapper box, clapper block, tool post and
hinge pin)
 Slide is attached to a swivel base and allows the cutting tool to move upward and
downward
  Clapper box is attached to the slide with a pivot screw and clamping nut and
allows the cutting tool to rise slightly on the return stroke of the ram (the clapper
box can swivel to enable angular and vertical cuts; for horizontal cuts, the clapper
box is often set vertically)

 Tool post holds the cutting tool which is similar to the shape of a lathe cutting tool
 Down feed handle and graduated micrometer collar allows the setting of the
correct depth of cut
 Power is supplied to the shaper by a standard electric motor mounted at the back
of the main body. The drive is transmitted to the gear box by V- belts through a
multiple disk friction clutch

SHAPER TOOLS

 A removable handle to turn all feed screws and to adjust the length and the
position of the ram stroke
 Wrenches to lock the table and tool holder in position

OPTIONAL TABLE

 A swivel or rotating table allows for a greater freedom of machining.

 The amount of swivel is 45° on either side of the vertical centreline.
 The table is locked in position by three clamps.
CUTTING TOOLS

 Shapers are used to make many different cuts on flat surfaces and most cutting
tools are made from high speed steel (HSS); for cutting very hard materials,
tungsten carbide tools are used

Uses of shaper cutting tools

 Cutting horizontally right or left

 Cutting vertically right or left
 Use for grooving

The usual practice when working in a shaper is to make rough and then finish cuts

Rough cuts - made leaving a steel surface 0.80mm (1/32”) oversize and a cast iron
surface 0.25mm (.01”) oversize

Finish cuts - specified size are made with a square – nosed tool

Types of tool holders

NOTE: The slot in the tool holder for a shaper cutting tool is parallel to the shank;
the slot for a cutting tool in a lathe tool holder is inclined.

Several common problems that can be encounter in operating a shaper:

 Too high cutting speed

 Poor setting of the tool
 Poorly secured workpiece
 Incorrect cutting tool angle

NOTE: Be sure to watch for and correct any of these problems in order to help
ensure a quality job with shaper
TYPES OF CUT

Horizontal Cuts Vertical Cuts

Combined Cuts Angular Cuts

Chamfers

Slots

Serrations Form Cuts

WORK HOLDING DEVICES

 Workpiece vary in size and shape so numerous work holding devices are
available to support or hold work to be cut on a shaper

Common work holding device:

 Vise
 Hold – downs
 Parallels
 Angle plate
 Clamps and bolts

NOTE: Work must be held securely before operating the shaper

Vise

 A vise, fastened to the shaper table, is used to hold most of the work in place for
machining on the shaper.
 It has a movable jaw, a fixed jaw, and a base that is graduated in degrees.
 The vise can be rotated on its base to any desired angle.
 A workpiece in the vise is held either parallel to or at right angles to the ram.

Hold-downs

 Hold-downs are used when machining thin stock.

 Made of steel or cast iron, hold-downs are wedge shaped, with the thick edge
bevelled 2° or 3°.
 When brought against the work, the thin edge presses downward, holding the
workpiece rigid for efficient and clean cuts.

Parallels

 Parallels are steel or cast iron bars with opposite sides parallel and adjacent
sides square.
 They are made in various sizes, are hardened and ground made from steel, and
are used to raise a workpiece above the vise jaws for machining.
 Paper feelers are placed between the parallels and the workpiece, then the vise
is tightened and the workpiece is hammered down with a soft hammer.
 When the feelers are securely in place you can be sure that the workpiece is
securely in place also.
Angle Plate

 An angle plate is sometimes clamped to a shaper table so that a workpiece can

be held securely when shaping one surface perpendicular to another.
 Before clamping the workpiece to the angle plate, check it with steel square to be
sure that the angle plate is square to the table.
 If the angle plate is not square, use paper shims under the corners in contact
with the table to make it square.

Mounting a Workpiece

1. Clean the workpiece and the vise.

2. Select parallels which will raise the workpiece 6 mm (1/4") above the vise jaws.
3. Set parallels and the workpiece in between the vise jaws.
4. Place paper feelers between the parallels and the workpiece.
5. Tighten the vise.
6. Tap down the workpiece with a soft-faced hammer until all paper feelers are
tightly held in place. The workpiece is now securely mounted in place.

Setting Shaper Stroke Length and Position

1. Correctly mount the workpiece in the vise.

2. Measure the length of the workpiece and add 25 mm (or 1") to determine the
length of stroke.
3. Use the start-stop button or the stroke regulator shaft crank and move the ram to
the back end of its stroke.
4. Loosen the stroke regulator locknut.
5. Turn the stroke regulator shaft until the stroke indicator shows the desired stroke
length.
6. Tighten the stroke regulator locknut.
7. With the ram still at the back end of its stroke, loosen the ram positioning lock.
8. Pull the tool head and the ram (or turn the ram adjusting screw) until the tool bit
is within 12 mm (1/2") of the workpiece.
9. Tighten the ram positioning lock.
10. With the cutting tool clear of the workpiece, start the machine and check that the
tool bit clears each end of the workpiece by 12 mm (1/2"); if so, the shaper stroke
length and position are now correctly set.

Setting Table Feed

 When machining horizontal surfaces, the table automatically feeds the workpiece
secured to it toward the cutting tool on the return stroke of the ram. If the table
 feed were to operate on the cutting or forward stroke, the cutting tool would be
damaged and the work surface would be made rough and irregular.

 The crank-gear shaft turns gear A. Gear A turns gear B. Gear B has the
connecting rod fastened to it. The connecting rod moves the mechanism to which
the pawl is attached. Moving the pawl causes the sprocket wheel to turn. As the
sprocket wheel turns, so does the table feed screw shaft, which moves the table
on the return stroke. The rate of feed is varied by moving the connecting rod
along the T-slot on gear B. The closer the connecting rod is to the centre of gear
B, the finer the table feed will be; the more the connecting rod is off-centre on
gear B, the more coarse the table feed will be. To disengage the table feed, raise
the pawl knob and turn the pawl 90°. This prevents the pawl from entering any of
the teeth of the sprocket wheel and so prevents activating the feed mechanism.

NOTE: Reversing the ratchet plunger reverses the feed direction.

When to use Vertical Feed

 Vertical feed is required when machining
vertical or angular surfaces.
 Either the down feed handle is turned by hand,
or a power down feed automatically engages,
and the workpiece is moved closer to the
cutting tool on each return stroke of the ram.
 When machining a vertical surface, the top of
the clapper box is swivelled away from the
surface to be machined in order to prevent the
cutting tool from binding on the work on its
return stroke.