Quote Originally Posted by Rogue View Post
If the screw has been turned down by that stage then would a shaft collar be sufficient for keeping it in place?
Possibly, but it's not ideal. The problem with a collar is, similar to the thrust bearings, it may be skewed on the shaft. A collar that clamps onto the shaft (ring with slit, bolt through slit to squash it) would be better. I would stick with having a thread. It depends what you're doing with the machine. If you're only cutting PCBs then pretty much anything will work ...