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How to Use a Center Punch and Prick Punch

Guide · Updated October 28, 2026

A prick punch has a sharp point (about 30° to 60°) for marking a layout intersection accurately. A center punch has a blunter 90° point that enlarges the mark so a drill point can start in it. Prick first, check the mark under a loupe, then center punch.

Check hole location

Measure the drilled location with an indicator and gage blocks, or a caliper from the edges. The free Gage Block Calculator builds the stack.

Step by step

Lay out: Dye the part and scribe two crossing lines at the hole location.
Place the prick punch: Tilt it to feel the point drop into the line intersection, then stand it vertical.
Tap lightly: One light hammer tap with a small ball-peen hammer.
Check with a loupe: The mark should sit exactly on both lines.
Draw it back if needed: Angle the punch toward the correct spot and tap to move the mark, then recheck.
Center punch: Seat the 90° punch in the prick mark and tap firmly to enlarge it to roughly the drill web size.
Spot drill then drill: Start with a spot or center drill, then the final drill.

Worked example

A 3/8 in hole is located 1.250 in from two edges. After pricking, the loupe shows the mark 0.005 in toward one edge. Tilt the prick punch about 20–30° toward the correct position and tap; the mark grows on that side and its center shifts. Recheck: now on the lines. Center punch to about 0.060 in diameter, which is a little larger than the web of a 3/8 in drill (about 0.05–0.06 in), so the chisel edge seats in the mark instead of walking. Spot drill with a 90° spot drill, then drill. By hand this usually lands within about 0.005 in; to hold 0.001 in, locate the hole on the mill with an edge finder or DRO instead of a punch mark.

Automatic punches

A spring-loaded automatic center punch fires with one-handed pressure, which leaves the other hand free and makes repeat marks consistent. Most adjust their striking force by turning the cap. They are great for sheet metal and many marks, but a separate prick punch still gives the most accurate first mark.

Common problems

Drill walking means the punch mark is too small for the drill web or the drill is dull; punch deeper or spot drill first. A mark off the line means it was not checked before center punching, and center punching only makes the error bigger. Double marks come from a punch that bounced; hold it firmly. Punching near an edge can bulge the edge on thin stock; back it up on a solid block.

Tips

FAQ

What is the difference between a prick punch and a center punch?

A prick punch has a sharp 30–60° point for accurate marking; a center punch has a 90° point that enlarges the mark for drilling.

How do I correct a punch mark that is off?

Tilt the prick punch toward the correct spot and tap to draw the mark over, then recheck.

How accurate is drilling from a punch mark?

Usually within about 0.005 in with a spot drill; less without one.

Is an automatic center punch worth it?

Yes for repeat marks and sheet metal; adjust the force with the cap.

How do I get better than 0.005 in?

Locate on a mill with an edge finder or DRO rather than a punch mark.

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