[ I asked Dick what is the problem.  -- Robbie ]

Hallo Robbie -- Details for the trackerbar tool.

I would like to check if the top roll is parallel to the bottom roll,
and also that the trackerbar is parallel to the top and the bottom
roll.  The tool that I have in mind looks like a depth tool for
clocks.

Best wishes from sunny Utrecht (but only this day)

Dick van Minnen
Museum van Speelklok tot Pierement
Utrecht
Pays Bas.