The only way I know how to create knurls is by using a helix, making a cut sweep with the helix and mirroring. This works on normal cylindrical bodies that aren't tapered. However, in order to do this to a frustrum, I need a way to project the helix onto the surface of the frustrum, but I'm not sure how. Using the taper feature on the helix is meh because although the tapered angle of the frustrum is 86 deg, I tried putting it in but I couldn't go above 4 deg so I have no clue. Any tips?
If there's another way to do this (that does not involve adding knurled appearance on the surface), I'm all ears.