IRWIN 63120 5/16-Inch M35 Cobalt Jobber Drill Bit
IRWIN 63120 is a single jobber-length cobalt-HSS bit with a 5/16-inch cutting diameter. Its separately listed overall and flute lengths help buyers check reach without confusing the total bit length with usable drilling depth.
Specifications and included details
- 5/16-inch cutting diameter and straight shank of the same diameter.
- 4-1/2-inch overall length and 3-3/16-inch flute length.
- M35 HSS with 5% cobalt; gold oxide finish.
- 135-degree split point and right-hand clockwise cutting direction.
Before ordering
Confirm the hole size, chuck fit and required flute reach. Select operating conditions for the workpiece material and bit instructions; cobalt content does not establish a universal hardened-steel rating or guarantee that every hole can be started without preparation.
Product questions and answers
Is this a left-hand extraction drill?
No. The listed cutting direction is right-hand, clockwise.
Does the gold finish mean cobalt is only a coating?
No. The material is M35 HSS with 5% cobalt, while gold oxide is a separate finish.
Can I treat 4-1/2 inches as cutting depth?
No. That is overall length. Flute length is 3-3/16 inches and the setup adds further limits.
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