Knurling presses or cuts a pattern of small ridges into a round surface on a lathe. A diamond knurl gives a firm grip on knobs, handles and thumb screws; a straight knurl helps parts press into plastic or soft metal and stay put. The pattern is set by the knurl wheel's pitch and angle.
Quick facts
- Patterns
- Straight, diagonal, diamond (cross)
- Common pitches
- About 0.5–2 mm (0.0197–0.0787 inch)
- Methods
- Form (pressing) or cut knurling
- Diameter change
- Form knurling raises the diameter slightly
- Machines
- Centre lathe, CNC lathe, sliding head lathe
- Usually priced
- Added to the turning cost per part
Form or cut knurling?
| Form knurling | Cut knurling | |
|---|---|---|
| How | Wheels press metal into a pattern | Wheels cut chips like a tool |
| Diameter | Grows a little | Stays close to size |
| Force on part | High | Lower, good for thin parts |
| Finish | Good | Sharper, cleaner |
Typical uses
- Knobs, thumb screws and handles
- Inserts pressed into plastic mouldings
- Shafts pressed into hubs
- Decorative finish on tools and fittings
What to send
- Drawing showing pattern type, pitch and length
- Diameter before and after knurling
- Material
- Quantity
Need knurling done?
Post your requirement free. Workshops that take your kind of work see it and get in touch. You only talk to the ones that fit.
Get startedRelated
Related job work
Questions
- Does knurling change the diameter?
- Form knurling raises it a little because metal is pushed up into the ridges. Allow for it on the drawing, or turn the blank slightly undersize.
- Diamond or straight knurl?
- Diamond for grip by hand; straight where a part must press in and resist turning.
- Can stainless steel be knurled?
- Yes, though it needs more force; cut knurling often gives a cleaner result on stainless.
The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 23 October 2026.