This is an adapter for holding a 1 inch internal-diameter PVC pipe into my mini-lathe. I wanted to knurl the plastic pipe for use as an exerciser handle. One side was clamped internally with a small three-jaw chuck; this adapter was put into the other end and a tailstock center was then used on the adapter. Printed from Overture PLA with 6 outer perimeters and 5% infill.

The stl file is included; if you need to adapt for a different size pipe the model can be accessed at https://www.tinkercad.com/things/2L5QyLIEhyK?sharecode=ThIG6cetdygONYEEd8RPtCkgxwkakioqorjX1EPld_0