UDC 622’243’5’051 IS:8166 -1988
Indian Standard ( Reaffirmed 1999 )
SPECIFICATION FOR
ROTARY DRILL BITS FOR DRILL~ING
PRINCIPALLY IN COAL
( First Revision )
1. Scope - Covers the-requirements for rotary drill bits used for drilling holes, The tools are mprinci-
oally for use in coal but are applicable to other materials having appropriate driving characteristics.
1.1 This standard also covers the pilot and reamer bits for drilling large diameter holes.
2. Types
a) Type A - One piece bits, and
b) Type B - Two piece bits consisting of pilot and reamer bits.
3. Nominal Sizes
-_
Type 14 Type 6
Pilot Reamer
35
:35 7”:
x: -
52 - -
Q. Dimensions
4.A Shanks
All dimensions in millimetres.
Typeof D, D, L, i L* 4 L4 4 R,
Bit +;I5 1 &0’4 Max kO.3 *%3 Max
-o”.lO -:.25 --00.33
--
A 12’7 8’6 23 29’9 39’3 9’7 13’1 3’2 0’3
B 12’7 8’6 40’5 47’4 57’2 9‘7 13’1 3’2 0’3
Adopted 18 July 1988 0 April 1989, BIS Or 3
I
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MAW
NEW DELHI 110002
4.2 Body
4.2.1 Type A bits and pilot bits for Type B bits
WATER GROOVE IF
All dimensions in millimetres.
--
Nomi- Cut- Tip Tip Tip Tip Tenon Core Body Lead Body Overall Gap
nal ting Width Cham- Height Thick- Dia Width Width Length Length Hei-
Size Dia fer ness L ght
X Y W z F G H J K M
$76 Min iwe TYPO
A B
35 35 14 4 19 20 22 32 64 52 91’3 109.2 24
38 38 14 4 19 21 19 32 76 52 91’3 - 27
43 43 16 4 24 22 22 40 76 66 95’3 113’2 30
52 52 19 6 25 29 24 49 127 60 99’3 - 32
4.2.2 Reamer bits for Type B bits
? I/_ 3 TIP. THICKNESS
OSITIVE
DRAWN
CORNER RAD K
17.53
lPT0~ }2-y
All dimensions in millimetres.
Nominal Tip Tip Heal Tip Bit Bit Gap Gap Corner Slot Clearance
Size ““zn” Width Cham- Radius Length Width Height Width Height Radius Depih Angle
fer
A X Y D W F G H J K L 8
+0*51
0
63 63 14 4 10 19 48 51 9 25 3 9 15” NEG
75 75 16 4 16 24 51 51 11 25 6 6 3” POS
IS : 8166 - 1988
5. Material
a)’ Shank and Body - High tensile steel with 0’55 percent carbon, Min.
b) Tips - Tungsten carbide conforming to IS : 4005-1967 ‘Specification for tungsten carbide
for mining tools’. Grade used shall be at the option of the purchaser.
6. Designation - A rotary drill bit of Type A, nominal size 38 and having tip of H grade of tungsten
carbide shall be designated as:
Rotary Drill Bit A38H
7. Hardness - 210 HV, /Win for bit bodies.
8. General Requirements
8.1 The bit body shall allow an unrestricted flow of cuttings away from the bit when the latter is
fitted into the rod.
8.1.1 The attachment of the bit to the drill rod shall be streamlined to give unobstructed flow of
the cuttings.
8.2 The tips shall be firmly brazed to the body of the bits.
8.3 Rotary drill bits shall be supplied with or without ~water grooves as specified by the purchaser.
8.4 Rotary drill bit shall have~rake angle normally of $3”. However, if required by the purchaser,
rotary drill bit with 0 to -4” rake angle may be supplied.
9. identification - Except for the shank, the bits shall be painted with the colour appropriate to the
grade of tungsten carbide used in the manufacture of the tip (see IS : 4005 - 1967 ).
10. Marking - Each rotary drill bit shall be marked on the driving flats with the following:
a) Manufacturer’s name or trade-mark;
b: Letter H, M, T or XT to identify the grade of tungsten carbide; and
c) Nominal size.
10.1 Standard Marking - Details available with the Bureau of Indian Standards.
EXPLANATORY NOTE
This standard was first published in 1976. This revision is based on the experience of the
manufacturing industry and the users of this product. The revision incorporates options for water
groove and rake angle, and tolerances on tip width, tip height and gap height have been deleted.
While preparing this standard, considerable assistance has been derived from the following:
IS0 1717-1974 Rock drilling - Rotary drill rods and rotary drill bits for dry drilling - Connecting
dimensions. International Organization for Standardization.
BS 2593 : 1964 Specification for rotarv drill rods and tunasten carbide tipped rotary drill bits for
dry drilling, principally in coal. British Standards In&tution.
N.C.B. Specification No. 148/1967 Positive rake rotary drill bits, 12 in dia. National Coal Board,
London.
N.C.B. Specification No. 543/l 968 Rotary drilling bits and reamer bits other than 1; in dia.
National Coal Board, London.
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Printed at Printrade, New Delhi, India
