Jimping file???

[J W Bensinger]

I've been doing thumb knurling for years with sharp triangle files. If you've steady hands (and start each cut very carefully) you can do good work that way, including on concave surfaces

 

[Fish30114]

JW, great pic, of great work! I have some acquaintance maker friends some of whom like and do really cool filework, that looks as good as any I've seen from anywhere. Thanks for the input brother

 

[Ja Baudin]

What ive used in the past it a thread file. They usually have 8 different sides so you can choose how far apart you want your lines. They look like this

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