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M42 HSS 8% Cobalt Twist Drill Bits
M42 HSS 8% Cobalt Twist Drill Bits - Image 2
M42 HSS 8% Cobalt Twist Drill Bits - Image 3

M42 HSS 8% Cobalt Twist Drill Bits

Material: High-Speed Steel with 8% Cobalt Alloy
Surface : industrial-grade TiN gold finish
Flute Design: Spiral flutes for efficient chip removal
Shank Type: Standard straight shank (compatible with most drill chucks)
Available Sizes: 1mm-20mm (custom sizes available for bulk orders)

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Why Choose Us ?

  • Reliable Manufacturing Experience
  • Strict Quality Control
  • Flexible Customization & Support

Industrial Heavy-Duty Drill Bits for Stainless Steel, Hard Metal & High-Temperature Alloys

Product Overview

Our M42 HSS 8% cobalt twist drill bits are purpose-engineered for heavy-duty, high-difficulty industrial drilling operations, delivering exceptional performance in hard-to-machine materials that standard HSS drill bits cannot handle reliably.

Manufactured with 8% cobalt-alloyed M42 high-speed steel and premium TiN gold coating, these drill bits are the trusted choice for B2B partners including stainless steel fabricators, automotive component manufacturers, aerospace machining facilities, mold & die workshops, hardware distributors, and global MRO service providers. We deliver unrivaled batch consistency, extended tool life, and reduced total operational cost for high-volume production and continuous drilling applications.

Core Material & Engineering Advantages

Premium M42 High-Speed Steel with 8% Cobalt Content

Unlike standard HSS or 5% cobalt (M35) drill bits, our 8% cobalt M42 material delivers industry-leading performance for hard material machining:
  • Superior Red Hardness & High-Temperature Stability: Maintains exceptional cutting edge hardness even at extreme temperatures up to 600°C generated during continuous high-speed drilling of hard metals, eliminating edge softening, chipping, and premature wear.
  • Outstanding Wear & Abrasion Resistance: 8% cobalt alloying significantly boosts material toughness and abrasion resistance, extending service life by 3-5x compared to standard HSS drill bits, and 2x compared to 5% cobalt drill bits in stainless steel applications.
  • Exceptional Impact Resistance: Optimized metallurgical structure reduces breakage risk in heavy-duty, interrupted cutting operations, minimizing unplanned downtime and tool replacement costs for your production line.

Advanced TiN (Titanium Nitride) Gold Coating

The industrial-grade TiN gold finish provides critical functional benefits for heavy-duty drilling:
  • Increases surface hardness to 85+ HRC, further enhancing wear resistance and extending tool lifespan
  • Reduces friction between the drill bit and workpiece, enabling smoother chip evacuation, lower cutting heat buildup, and faster penetration speeds
  • Delivers excellent oxidation resistance, making it suitable for both wet and dry high-speed drilling operations

Precision Fully Ground Manufacturing

Every drill bit undergoes full CNC grinding across the flute, shank, and cutting edge, ensuring:
  • Ultra-tight dimensional tolerance and near-perfect concentricity, eliminating radial runout for straight, round, burr-free holes with zero deviation
  • Consistent batch-to-batch performance, critical for high-volume automated production lines
  • Optimized flute geometry for unobstructed chip removal, even during deep-hole drilling in viscous materials like stainless steel

Ideal Industrial Applications

Our 8% cobalt twist drill bits are the industry standard for:
  • Stainless steel fabrication & kitchenware manufacturing
  • Automotive & heavy truck component machining
  • Aerospace & defense parts production
  • Mold & die manufacturing
  • Medical device & precision instrument machining
  • Oil & gas equipment repair & production
  • Industrial MRO & maintenance operations
  • Metalworking job shops & contract manufacturing

 

Application
HSS Grade
Iron
Aluminum
Carbon Steel
Tile
Plastic
Stainless Steel
4241
YES
YES
NO
NO
YES
NO
4341 YES YES YES NO YES YES
6542(M2)
YES
YES
YES
NO
YES
GOOD
M35 (Co 5%)
YES
YES
YES
NO
YES
VERY GOOD

 

DESCRIPTION OF HSS C W Mo Cr V Co Si Mn P S
% % % % % % % % % %
W4Mo3Cr4V(4341) 0.88-0.98 3.5-4.5 2.5-3.5 3.8-4.4 1.2-1.8 0.5-1.2 0.2-0.4 <=0.03 <=0.03
W6Mo5Cr4V2(M2) 0.8-0.9 5.5-6.75 4.5-5.5 3.8-4.4 1.75-2.2 – 0.2-0.4 0.2-0.4 <=0.03 <=0.03
W6Mo5Cr4V2Co5(M35) 0.9-0.95 5.5-6.5 4.5-5.5 3.8-4.4 1.75-2.2 4.5-5.5 0.2-0.4 0.2-0.4 <=0.03 <=0.03
W2Mo9Cr4V2Co8(M42) 1.05-1.15 1.15-1.85 9.0-10.0 3.5-4.25 0.95-1.25 7.75-8.75 0.15-0.65 0.15-0.4 <=0.02 <=0.025

 

Metric size

DIA.(mm)
OVERALL LENGTH(mm)
WORKING LENGTH(mm)
1
34
12
1.5
43
20
2
49
24
2.5
57
30
3
61
33
3.5
70
39
4
75
43
4.5
80
47
5
86
52
5.5
93
57
6
93
57
6.5
101
63
7
109
69
7.5
109
69
8
117
75
8.5
117
75
9
125
81
9.5
125
81
10
133
87
10.5
133
87
11
142
94
11.5
142
94
12
151
101
12.5
151
101
13
151
101
13.5
160
108
14
160
108
14.5
169
114
15
169
114
15.5
178
120
16
178
120
16.5
184
125
17
184
125
17.5
191
130
18
191
130
18.5
198
135
19
198
135
19.5
205
140
20
205
140

Imperial size

DIA. OVERALL LENGTH (INCH) WORKING LENGTH (INCH) DIA. OVERALL WORKING LENGTH (INCH) DIA. OVERALL WORKING LENGTH (INCH)
1/64″ 3/4″ 3/16″ 15# 3-3/8″ 2-3/16″ 61# 1-/5/8″ 11/16″
1/32″ 1-3/8″ 1/2″ 16# 3-3/8″ 2-3/16″ 62# 1-1/2″ 5/8″
3/64″ 1-3/4″ 3/4″ 17# 3-3/8″ 2-3/16″ 63# 1-1/2″ 5/8″
1/16″ 1-7/8″ 7/8″ 18# 3-1/4″ 2-1/8″ 64# 1-1/2″ 5/8″
5/64″ 2″ 1″ 19# 3-1/4″ 2-1/8″ 65# 1-1/2″ 5/8″
3/32″ 2-1/4″ 1-1/4″ 20# 3-1/4″ 2-1/8″ 66# 1-3/8″ 1/2″
7/64″ 2-5/8″ 1-1/2″ 21# 3-1/4″ 2-1/8″ 67# 1-3/8″ 1/2″
1/8″ 2-3/4″ 1-5/8″ 22# 3-1/8″ 2″ 68# 1-3/8″ 1/2″
9/64″ 2-7/8″ 1-3/4″ 23# 3-1/8″ 2” 69# 1-3/8″ 1/2″
5/32″ 3-1/8″ 2″ 24# 3-1/8″ 2″ 70# 1-1/4″ 3/8″
11/64″ 3-1/4″ 2-1/8″ 25# 3″ 1-7/8” 71# 1-1/4″ 3/8″
3/16″ 3-1/2″ 2-5/16″ 26# 3″ 1-7/8″ 72# 1-1/8″ 5/16″
13/64″ 3-5/8″ 2-7/16″ 27# 3” 1-7/8″ 73# 1-1/8″ 5/16″
7/32″ 3-3/4″ 2-1/2″ 28# 2-7/8″ 1-3/4″ 74# 1″ 1/4″
15/64″ 3-7/8″ 2-5/8″ 29# 2-7/8″ 1-3/4″ 75# 1″ 1/4″
1/4″ 4″ 2-3/4″ 30# 2-3/4″ 1-5/8″ 76# 7/8″ 3/16″
17/64″ 4-1/8″ 2-7/8″ 31# 2-3/4″ 1-5/8″ 77# 7/8″ 3/16″
9/32″ 4-1/4″ 2-15/16″ 32# 2-3/4″ 1-5/8″ 78# 7/8″ 3/16″
19/64″ 4-3/8″ 3-1/16″ 33# 2-5/8″ 1-1/2″ 79# 3/4″ 1/8″
5/16″ 4-1/2″ 3-3/16″ 34# 2-5/8″ 1-1/2″ 80# 3/4″ 1/8″
21/64″ 4-5/8″ 3-5/16″ 35# 2-5/8″ 1-1/2″ A 3-/7/8″ 2-5/8″
11/32″ 4-3/4″ 3-7/16″ 36# 2-1/2″ 1-7/16″ B 4″ 2-3/4″
23/64″ 4-7/8″ 3-1/2″ 37# 2-1/2″ 1-7/16″ C 4″ 2-3/4″
3/8″ 5″ 3-5/8″ 38# 2-1/2″ 1-7/16″ D 4″ 2-3/4″
25/64″ 5-1/8″ 3-3/4″ 39# 2-3/8″ 1-3/8” E 4″ 2-3/4″
13/32″ 5-1/4″ 3-7/8″ 40# 2-3/8″ 1-3/8″ F 4-/1/8″ 2-7/8″
27/64″ 5-3/8″ 3-15/16″ 41# 2-3/8″ 1-3/8″ G 4-/1/8″ 2-7/8″
7/16″ 5-1/2″ 4-1/16″ 42# 2-1/4″ 1-1/4″ H 4-/1/8″ 2-7/8″
29/64″ 5-5/8″ 4-3/16″ 43# 2-1/4″ 1-1/4″ I 4-1/8” 2-7/8″
15/32″ 5-3/4″ 4-5/16″ 44# 2-1/8″ 1-1/8″ J 4-/1/8″ 2-7/8″
31/64″ 5-7/8″ 4-3/8″ 45# 2-1/8″ 1-1/8″ K 4-/1/4″ 2-15/16″
1/2″ 6″ 4-1/2″ 46# 2-1/8″ 1-1/8″ L 4-/1/4″ 2-15/16″
1# 3-7/8″ 2-5/8″ 47# 2″ 1″ M 4-3/8″ 3-1/16″
2# 3-7/8″ 2-5/8″ 48# 2″ 1″ N 4-3/8″ 3-1/16″
3# 3-3/4″ 2-1/2″ 49# 2″ 1″ O 4-1/2″ 3-3/16″
4# 3-3/4″ 2-1/2″ 50# 2″ 1″ P 4-5/8″ 3-5/16″
5# 3-3/4″ 2-1/2″ 51# 2″ 1″ Q 4-3/4″ 3-7/16″
6# 3-3/4″ 2-1/2″ 52# 1-7/8″ 7/8″ R 4-3/4″ 3-7/16″
7# 3-5/8″ 2-7/16″ 53# 1-7/8″ 7/8″ S 4-7/8″ 3-1/2″
8# 3-5/8″ 2-7/16″ 54# 1-7/8″ 7/8″ T 4-7/8″ 3-1/2″
9# 3-5/8″ 2-7/16″ 55# 1-7/8″ 7/8″ U 5″ 3-5/8″
10# 3-5/8″ 2-7/16″ 56# 1-3/4″ 3/4″ V 5″ 3-5/8″
11# 3-1/2″ 2-5/16″ 57# 1-3/4″ 3/4″ W 5-1/8″ 3-3/4″
12# 3-1/2″ 2-5/16″ 58# 1-5/8″ 11/16″ X 5-1/8″ 3-3/4″
13# 3-1/2″ 2-5/16″ 59# 1-5/8″ 11/16″ Y 5-1/4″ 3-7/8″
14# 3-3/8″ 2-3/16″ 60# 1-5/8″ 11/16″ Z 5-1/4″ 3-7/8″

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