I just turn them from a piece of mild steel and polish them a bit, then drill a 1/4" hole in the center while it's in the lathe, tack weld a 1/4" rod in that is long enough to allow it to be driven under the dent. My mandrels get a generous radius on the nose and I polish that radius and grease the mandrel so it drives under the dent nicely without damage. It seems like no two jobs I've done had the same bore diameter.
I did use a high precision gauge pin recently for a .410 dent.
Last edited by Chuck H; 03/22/12 09:19 AM.
