5c Z axis datum stop ring for different diameter parts.

[@AlHackel]

This is a great idea! Thanks for sharing.

[@alansmith5690]

Struggled to get this till the end. It needs the relief for the collet face. Great idea.

[@machinists-shortcuts]

Thanks. The relief is larger in diameter than the collet end. The depth is almost 1mm deeper than the collet protrusion at rest.