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How to Sharpen a Drill Bit

Guide · Updated October 28, 2026

A sharp, evenly ground drill cuts to size, starts true and lasts. Hand sharpening on a bench grinder takes practice, but the geometry is simple: the right point angle, some lip relief, and two equal lips.

Check hole size

Check test holes with a pin gage or a mic verified against gage blocks. Check it with a mic you've verified against gage blocks; the free Gage Block Calculator builds the stack.

Step by step

Dress the wheel: True the face of the grinder wheel so it is flat and sharp.
Set the angle: Hold the drill at about 59° to the wheel face for a 118° point.
Lip horizontal: Hold one cutting lip horizontal and touch it to the wheel.
Add relief: Rotate and drop the shank slightly as you grind so the heel sits below the lip, giving about 8–12° relief.
Do the other lip: Turn the drill 180° and grind the second lip the same way with the same number of passes.
Check it: Check point angle and lip length with a drill point gage; the chisel edge should sit at about 120–135° to the lips.
Test: Drill a test hole and check its size and that both lips make chips.

Worked example

A 1/2 in drill cuts a 0.512 in hole and one spiral chip is heavier than the other. The gage shows one lip is about 1/64 in longer, so the point is off center. Grind the long lip down until both match on the gage. The next test hole measures 0.503 in with equal chips.

Point angles

118° is the general-purpose point for mild steel. 135° split points suit harder steel and stainless and resist walking. Brass and plastics need the lips dubbed off flat to stop the drill grabbing.

Web thinning

As a drill is shortened by sharpening, the web gets thicker and needs more thrust. Thin the web at the point with the corner of the wheel, keeping both sides equal.

Tips

Use it well: drilling speeds and feeds.
Start holes true: spot drilling.
Deep holes: peck drilling.
Sizing holes: reaming a hole.

FAQ

What angle do I sharpen a drill bit?

Usually 118° included, so each lip is about 59° to the drill axis.

How much lip relief does a drill need?

About 8 to 12° for general drilling, a little more on small drills.

Why does my drill cut oversize?

Usually unequal lip lengths or angles put the point off center.

Why does my drill squeal and not cut?

It has no lip relief or the heel is rubbing.

Should I thin the web?

Yes on drills that have been shortened a lot by sharpening.

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