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How to Knurl on a Lathe

Guide · Updated October 28, 2026

Knurling rolls (or cuts) a diamond or straight pattern into a turned diameter for grip. A good knurl comes from the right blank size, a square tool and enough pressure on the first touch.

Size the blank

Measure the blank diameter with a mic you've checked against gage blocks; the free Gage Block Calculator builds the check stack.

Step by step

Pick the tool: Use a scissor or cut-type knurler for small lathes; a bump knurler needs a rigid machine.
Turn the blank: Turn the diameter round and true; a blank close to a multiple of the knurl pitch tracks more cleanly.
Square the tool: Set the wheels on center height and square to the work, or tilted slightly so one wheel edge leads.
Set slow speed: Run slow, often 60–100 RPM on a 1 in part, and flood with oil.
Start hard: Engage firmly on the first contact, about half the knurl width on the part, so the pattern forms in one try.
Feed along: Power feed along the length at roughly 0.010–0.020 in/rev with oil.
Deepen and finish: Take one or two more passes until the diamonds come to points, then chamfer the ends.

Worked example

1.000 in blank with a medium 21 TPI (diamond) knurl: circumference is about 3.142 in, which is about 66 pitches — close to whole, so it should track. Run about 80 RPM, engage hard, feed 0.015 in/rev.

Double tracking

A doubled or fuzzy pattern means the wheels did not lock into one track. Pressure was too light on first contact, or the blank size splits a pitch. Change diameter by a few thousandths or re-engage harder at a fresh spot.

Bump vs scissor knurlers

A bump tool pushes radially and loads the cross slide and spindle bearings. A scissor (clamp) tool squeezes from both sides, so it is easier on small lathes.

Tips

Knurling grows the diameter — turn the blank a few thousandths under the finished size.
Set center height first; see setting tool height.
Support long parts with the tailstock; see aligning a tailstock.
Use plenty of oil and brush chips from the wheels.

FAQ

What speed should I knurl at?

Slow — roughly a quarter to a third of turning speed, often 60–150 RPM depending on diameter.

Why is my knurl double tracking?

Too little pressure on first contact or a blank diameter that does not suit the pitch.

Does knurling change the diameter?

Yes, form knurling raises the diameter a few thousandths as metal is displaced.

Can I knurl on a small lathe?

Yes, a scissor-style knurler keeps load off the spindle bearings.

Should I use oil when knurling?

Yes, flood with cutting oil to clear chips and protect the wheels.

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