How to Mill a Round End on a Square Bar Safely?

For people without rotary tables: Put an endmill in the lathe chuck and use the end of it only. Most of the force is then downwards into the support piece and not trying to add rotation. Be careful at the 180 degree position not to mark the work with the other side of the cutter. Set up the pivot in the middle of the cross-slide so there is room to place some sort of stop at 0 and 180 degrees.

I considered that too, but leaving the adjacent surface untouched would be a challenge I imagine!

.

A properly finished safe-edge on the file should see to that, Paul

[but it does involve quite a lot of effort to get one]

MichaelG.

Should that not be Button as you will only be able to run the file on a button on one side

The part looks a bit long but another method is to put a pin through the hole and rest that on the top of your vice jaws and make a series of cuts altering the angle of the work for each one, this gives a faceted finish that can then be filed quite easily to a curve.

Edited By JasonB on 29/11/2016 17:33:57

JB, Dunno what scale your pics are, but he is only starting with 18 x 18 mm.

Yes but his part looks about 100mm long so the pivot pin won't rest on his vice jaws as the cuts get towards the end unless it is a very big one.

Edited By JasonB on 29/11/2016 19:06:38

JasonB has a good eye for dimensions: the bar is 18x18x100.

I re-tried pivoting this afternoon with much better results. Turning the work into the cutter (not climbing!) and cutting a full semicircle from 0 to 180° was straightforward. In retrospect cutting from 90° to 180 and back to 0° was a daft thing to do. I wasn't able to try the rotary table: visitors stopped play.

Dave