Knurling confusion
Hey, I was hoping someone here could help me because I'm losing my mind over something that seems like it should be simple. I'm a new machinist and this is my first time tackling knurling. I have a single wheel bump style knurling tool with a diamond shaped 20tpi wheel inserted. When stationary, the knurling produces is great, but any time I try to feed to make a larger knurl, it just comes out awful. I've played with feed rates, speeds, and depth of cut. I've gone online to look for answers but every source I find either disagrees with every other source and/or just doesn't work when I try their methods. The best I've gotten so far is the image attached. If anyone could give some advice or point me to somewhere that can actually help, it would be greatly appreciated. At this point I just feel like I'm running my head into a wall.
1 reply
tl;dr: make yourself a clamp-style knurling wheels holder.
i'll assume your lathe is a manual one.
i've never gotten good results with the bump-style knurling tools, even though i follow the calculations precisely, undersized or oversized. i am talking about the dual-wheel type knurling tools, i have a single-wheel tool that knurls straight, but honestly, i don't remember if it worked or not (probably was a disappointment as well).
one day i was bored, and decided to make myself a clamp-style tool. didn't measure much, just made it up as i went along. i used a manual hacksaw to cut and split the steel flat bar stock. it was a tall order but it got done.
i never failed a knurling since (although i don't do much knurling if i am honest).
the biggest problem is rigidity, knurling with bump-style tools requires an insane level of rigidity. i didn't have it, and by the looks of things, you don't either.