I store my espresso tamper on top of the convenient flat surface of the "doser" of my Rancilio coffee grinder. Unfortunately, the vibration of the grinder often caused the heavy tamper to move and eventually fall (loudly!) to the counter top.

I created this ring to store the tamper so this doesn't happen any more. Works great!

My tamper is 2 9/32-inch (about 58 mm) in diameter. The hole in the retainer ring is 61 mm, which leaves so wiggle room. I included the OpenSCAD file if you want to adjust the size for your different size tampers.

The screw holes were intentionally left small. I drilled them out to fit self-tapping screws for attaching to the lid. You could also glue the ring to the lid if you prefer.