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How to Inspect a Drill Bit in 60 Seconds Before You Use It

Most machinists just grab the next bit out of the tray and go. Then they wonder why the hole came out oversized, why the bit ran hot, or why it walked across the surface before biting.

A 60-second inspection before you chuck the drill prevents most of those problems. Here's the protocol.

Step 1: Check the Shank (5 seconds)

Look at the shank — the cylindrical section that goes into the chuck.

Pass: Round, undamaged, no visible deformation.

Fail: Flats from a slipping chuck, deformation, any visible crack. A damaged shank cannot be held concentrically. The bit will run with runout and cut oversized holes. Retire this bit.

Step 2: Check the Flutes (10 seconds)

Hold the bit up to a light and look down the length of the flutes — the helical channels that carry chips out of the hole.

Pass: Smooth, uninterrupted spiral. No cracks, no deep gouges, no packed material, no blue discoloration more than an inch back from the tip.

Fail conditions:

• Visible crack anywhere — retire immediately. In-hole breakage is a real risk and broken bits in holes are a significant recovery problem.
• Blue heat discoloration 2+ inches up the flute — the steel has lost temper. The bit will look sharp after grinding but the edge won't hold. Retire.
• Packed chips in the flutes — clean before use. Packed flutes can't evacuate chips and will cause binding.

Step 3: Check the Tip — Point Angle (10 seconds)

Hold the bit at eye level and look at the tip. Compare to a known good bit of the same type if possible.

• 135° (flatter tip): Common on split point bits and hard-material drills. Looks almost star-shaped at center. Correct for stainless, hard alloys.
• 118° (sharper tip): Standard general-purpose. More pointed. Correct for aluminum, mild steel, plastics.

What you're looking for: Is the tip symmetric? Both cutting edges should be visible and appear to be at the same angle. A visibly asymmetric tip means the bit has been resharpened unevenly or worn unevenly.

Step 4: Check Lip Height Symmetry (15 seconds)

This is the most critical and most commonly skipped check.

Lip height symmetry means both cutting edges are at the same height when you hold the bit tip-up. When one edge is higher than the other, that edge does all the cutting. The result: an oversized hole (sometimes 3–8 thousandths) and accelerated wear on one side.

How to check:

1. Hold the bit vertically, tip up
2. Look straight down at the tip — the two cutting edges should form a symmetrical "X" or "V" pattern
3. Rotate the bit 180° and compare — if one lip appears higher than the other from this angle, the symmetry is off

Pass: Both edges appear identical in height and angle from all rotations.

Fail: One edge is visibly higher or at a different angle. The bit will cut oversized holes and wear unevenly. Send for resharpening.

Step 5: Check for Split Point (5 seconds)

For split point bits: look at the very center of the tip. A split point has a secondary grind that creates two small additional cutting lips at center — you'll see it as a notch or "W" shape rather than a smooth chisel edge.

If the bit was originally a split point and the split is gone (it was resharpened away), it will still cut but will require more thrust and is more prone to walking. Note this when sending for resharpening.

The 60-Second Summary

Check	Pass	Fail — Do This
Shank	Round, no damage	Retire
Flutes	No cracks, no blue zones	Retire (crack) / Clean (packed chips)
Point angle	Symmetric, correct for material	Resharpen
Lip height	Both edges identical	Resharpen
Split point	Present if originally split point	Note on resharpen order

If it passes all five — chuck it and drill. If it fails one — either retire it or put it in the resharpen bin.

This takes 60 seconds. The payoff is correct holes, longer bit life, and fewer broken bits in workpieces.

Send your dull bits for resharpening →