Expanding Mandrels and Arbors

[JTiers]

A set of them of the type in the picture is handy.... they work quite well, and hold concentricity about in proportion to their cost and quality....... The sleeve is split, and expands on teh tapered part. they go between centers.

[Harold_V]

Well, these certainly give me a lot of ideas! I like the idea of making my own arbor to just the right size. I think I remember a photo somebody posted that tapped the end of the arbor for 1/8" NPT, then cutting two slits at 90º lengthwise. Put the wheel on the arbor, then screw in a pipe plug to tighten.

You're on the right track, but keep in mind a larger pipe plug can prove quite valuable if you have larger diameter work. The negative is you have a much coarser thread as you move up, so the tightening effort becomes greater.

It is generally a good idea to rough turn the desired diameter, then drill and tap, then split the piece. Consider 60° intervals for larger diameters. Debur the threads, install the plug and get it lightly snugged up, then finish machine the desired diameter and face the shoulder. When you back off the pipe plug, the turned diameter should relax enough to allow fast and easy installation of the part to be machined. Machining to size after all other operations are performed insures that it runs true.

I used these extensively in my years in the shop. Properly applied, they are a very nice holding tool.

Harold