Expanding Mandrels and Arbors

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: GlennW, Harold_V

JTiers
Posts: 422
Joined: Fri Jan 22, 2010 12:55 am
Location: Missouri

Post by JTiers » Tue Mar 23, 2010 10:34 pm

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.

Image

Harold_V
Posts: 19355
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Post by Harold_V » Wed Mar 24, 2010 12:54 am

Fender wrote: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

Post Reply