Machine Checking Gauge, Type MCG2, still manufactured by Renishaw Metrology. For evaluating the calibration of coordinate measuring machines and machine tools over 35 cubic feet in capacity.

Price for this one only: SOLD

Complete and unused in fitted mahogany case and with original instruction booklet as well as the original calibration sheets. I cannot find any blemish anywhere; there is no sign that this device was ever used, and it does not even have scratches on the case, which is made of Honduras (swietenia) mahogany.

The two closeups show the ruby balls used as pivot & contact points.

Claimed accuracy is +/- 0.5 microns. The worst deviation in these calibration traces is 0.2 microns. The sheets are in a sleeve tucked in a special spot in the cover of the case and are the original traces. The date of the testing is 1988.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

The images at left were scanned from the uncopyrighted original instruction manual and indicate schematically how the gage works. The "fishing rod" pivots on ruby balls at the central post, while the coordinate measuring machine's sensitive pickup "feels" the contact between another ruby ball that nudges up against a ruby ball at the tip of the "fishing rod." The pair of thin rods at the tip of the "fishing rod" keep the ruby balls from becoming disengaged while the "fishing rod" pivots in order to trace out the spherical calibration volume.