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.

Dynabrade 53533 Cone or Plug Grinder (Triple Extension)
Insize 6140, DEPTH BASE ATTACHMENT, suitable for calipers with beam width (w) .630", 6928640303579 