I built a flat recessed dimple die. Just used a peice of 1-5/8" OD tubing welded it to a peice of flat square1/8" thick plate that had a hole drilled in the center. On the backside of the plate I welded a nut. Then threaded a bolt up through. The bolt will help keep everything centered when you put it in tne hydraulic press. I stacked some washers inside the tubing to get the desired depth. You probanly could just tje tubing shkrter bjt i had the washers lying around and was too lazy, lol.