Yeah, the “real” machinists will be in a tizzy over these.
Do you have only a 3 Jaw Lathe Chuck??
These won’t win you any machining accuracy awards, but it you have a piece of square stock that you need to chamfer, drill a holes close to on-center, part or make part of it round…well, one of these is the only way you are going to do it on a 3 jaw chuck.
3D Printed with 100% infill. You’ll need to take a hacksaw and cut as in the pictures, deburr and tap your square stock in with a mallet.
If you are doing heavy cutting, let the piece cool from time to time as these are PETG plastic. Check jaw tightness from time to time and never stand inline with a lathe chuck.
They come in 1/4″, 5/16″, 3/8″, 1/2″ and 5/8″.
Sold separately, or as a set of five.