Re: [penturners] Mandrel?
Sorry to be so long in answering the question. You were wondering about
putting a dimple in the end of a 1/4" bolt to use as a mandrel. First
note that it will not be as accurate as a commercial mandrel which is a
hair off of 1/4". Having said that, you need a jig to accurately dimple
the end. Most accurate method I have found is:
1) using a drill press drill a 1/16" hole through a 1" thick piece of
maple or other hard wood.
2) in the same hole drill a 3/16" hole 1/2" deep
3) hold a 1/4" metal tap in the drill press and tap the 3/16" hole as
deeply as you can.
note!!!! turn the tap by hand, the drill press is merely an accurate
4) using the drill press as a guide, thread the bolt into the threaded
hole as far as you can.
5) you now have a jig to guide a 1/16 bit on center in the end of the
Optionally, you could hold the bolt in a chuck and the drill in the tail
stock, perhaps with a steady rest you could get an accurate center
God bless and safe turning