Spherometers are used by professional opticians and advanced telescope mirror
makers for monitoring the depth of the curve, or "sagitta", during coarse and fine
grinding glass operations.
For Sale: 8 inch precision spherometer with three (3) point ball feet and a dial
indicator. The span is extreme high precision machined 4.0000" to the center
bore, and the ball feet are precision 0.375" in diameter. The indicator locking
collar is improvised from a welded nut and nylon bushing, but it works very well.
Included is a dial indicator with 0.001" precision, 1" travel and a rounded probe
tip. Also, an excel spreadsheet for calculating your Radius of Curvature from
the precise sagitta measurements which can be taken with this instrument.