What is the general consensus on Caliper tolerances?

[DietCokeofEvil]

This is probably a lame question- but I'm a thread person that's been tasked with cleaning up caliper templates. What is the general consensus on caliper tolerances? There doesn't seem to be a "standard" for calipers- there is a NAVAIR spec, but that's a calibration procedure- not a standard like what I am used to seeing in threads.

NAVAIR for dial calipers basically says ±0.001 in./6 in, or ±0.001 in./ft. Fowler catalog gives 0.001 for 6" and 0.002 for 12". So for a 12" caliper would it be ±0.001 to 6" and then ±0.002 over 6-12"?

I don't understand Navair's tolerance- how can something be ±0.001 in./6 in, or ±0.001 in./ft? Any input would be helpful.

 

[BoardGuy]

I would go with the manufactures specification of 0-6”, +/- .001 and 6-12”, +/- .002” which is normal tolerance from most manufactures for both digital and dial calipers.

The military orders inspection kits to their own requirements and that may be what you are seeing with the NAVAIR document. Without knowing the specific NAVAIR document, you are getting this tolerance from, its hard to say.