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How to Deburr and Break Edges
Guide · Updated October 27, 2026
Burrs cause bad measurements, assembly trouble and cuts. Drawings often say "break all sharp edges", which typically means a small chamfer or radius, often around 0.005 to 0.015 in. Check your shop or drawing standard.
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Step by step
- Pick the tool: Use a swivel blade deburrer for edges, a countersink for holes, and files and stones for faces.
- Break evenly: Make the edge break small and even. Don't round the corner off.
- Protect critical faces: Keep tools off sealing and datum faces.
- Clean up: Blow off chips and wipe the part.
- Inspect: Check for burrs by feel and under good light, and measure after deburring.
Tips
- Chamfer sizes: see checking a chamfer.
- Burrs on gage blocks or setup tools ruin wringing and accuracy. Stone them lightly.
Related: chamfers and countersinks, drilling.
Worked example: breaking edges on a milled block
A milled steel block has sharp burrs along all top edges. Wipe off chips, then run a hand deburring tool along each edge at a steady angle, with light pressure, to raise a small, even chamfer. Follow with a fine file or stone held at about 45 degrees for one or two light strokes per edge. Run a fingernail or a cotton swab along the edge; if it catches, repeat. Clean the part again before measuring so loose burrs do not sit under the anvils.
FAQ
What does break sharp edges mean?
Remove sharpness with a small chamfer or radius, often 0.005 to 0.015 in. Check the drawing or your shop standard.
Why measure after deburring?
Burrs give false high readings, and heavy deburring can remove size.
Best deburring tool?
A swivel blade deburrer covers most edges, with countersinks for holes.
Should I deburr gage blocks?
Only stone off raised burrs, very lightly, with a flat stone.
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General shop information only — follow your gage manufacturer's instructions and your quality system.