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 20967, Portable Utility Cloth Roll 314D, P240 J-weight, 1 in x 20 yd, 7010290604 
