Hi. I just bought a used Sherline mill, and it came without any end mill holders. I looked at their website, and they cost $36 or more each. There is a little warning on the description saying that making these holders is harder than it appears, and that is why they cost so much. This is due to the way that they are attached to the spindle. There is no register, and concentricity comes entirely from the precision of the threads. I guess that the face of the collar enforces parallelism only. So, the threads must be cut to the exact depth. I am not too familiar with precision threading. On all the backplates for my South Bend lathe, I pay close attention to bore the register on size. Straightforward, simple, and they fit well. How bad can the runout be relying only on the threads? What would be the standard way of making such a holder? Would I first build a go gauge based on wire measurements of the actual Sherline spindle threads? How much closer would this get things?
I did a forum search, and there was not too much information, except possibly to bore the final diameter on the mill itself with a boring bar stuck in a vise. Unfortunately, the thread did not clearly indicate how much better this would be. In fact, it appeared to do a worse job.
I did a forum search, and there was not too much information, except possibly to bore the final diameter on the mill itself with a boring bar stuck in a vise. Unfortunately, the thread did not clearly indicate how much better this would be. In fact, it appeared to do a worse job.
