Used with standard outside micrometers with spindle .256″DIA to measure pitch diameter of screw threads.
Diameter accuracy: ?20_in. Cylindricity: 39_in.
Cylindricity: 1um. Hardness: HRC60.
Supplied with manufacturer inspection certificate.
Supplied with manufacturer inspection certificate.

3M 21639, PSA Cloth Disc 348D, 36 X-weight, 6 in x NH, Die 600Z, 7000148149
3M 95725, Venture Tape Metal Building Facing Tape 1552CW, White, 72 mm x 45.7 m, 7010313505 
