765timb new member

[765timb]

Hello, Just stumbled onto your site looking for an expandable mandrel for rings on a lathe. My interests are coin rings, turning pens, wood and plastic rings, robotics, 3D printing, electronics, ETC.

[mklotz]

A quick and dirty way to make an expanding mandrel is to turn a piece of stock to a diameter a bit less than the inside diameter of the ring, then drill and tap the end for a suitably sized tapered pipe plug. Saw four or six slits into the mandrel.

When the tapered plug is screwed into the mandrel, the leaves formed by the saw slits will expand to grip the inside of the ring.