What you guys use for a piston base tool?

I recently made a set of these using my originals which looked pretty sad after 38 years of existence. The originals I made from 1/2" plywood and they were beat. These are some scrap 1/2" poplar trim I had leftover from a house project.



I milled the slots in my mini mill. These look more solid that the plywood ones which ended there life in the fire pit.

Here using primitive technology, just some clamps and some pieces of wood.