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Irw in Cobalt Drill Bit Set 29-Piece

M42 cobalt with 8% cobalt content - highest cobalt grade for hardened steel

✎ PickHonest Research Desk▦ Updated October 15, 2026◷ 3 min read

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Best Overall

Irw in Cobalt Drill Bit Set 29-Piece

Irwin

M42 cobalt with 8% cobalt content - highest cobalt grade for hardened steel

  • M42 cobalt steel
  • 8% cobalt content
  • 135-degree split point
  • 29-piece 1/16 to 1/2 inch

Pros

  • M42 cobalt with 8% cobalt content - highest cobalt grade for hardened steel
  • 135-degree split point starts without a center punch on most surfaces
  • Irw in is the benchmark bit brand used by professional machinists
  • 29-piece coverage from 1/16 to 1/2 inch

Cons

  • Set price is high - individual bits available if only specific sizes are needed
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