Indent thing

A while back on this list, I think in regards to building a handwheel for
a CNC machine, someone mentioned the name of the part that gives
the indent feel. Basiclly it's a small threaded rod, hollowed out with a
spring and a ball inside. The ball sticks out the end a bit and would engage
a series of holes to give an indented feel. I looked them up at the time,
and now that I need one I can't remember the name. Have not been able
find the post in the archives since I can't remember the name of the damn
thing. Anyone??

Thanks
Bill