The specified tolerance for half-round jaws is ±32µin. (±0.80µm). However, because the
distance over the roll of these jaws is so difficult to measure, Webber reduces our
manufacturing tolerance to ±20µin. or ±0.50µm to allow for any measuring errors.
For B89.1.9 specifications, click here.
When these jaws are included as pairs in sets, they are matched together so that the sum of
the errors is not larger than ±20µin. or ±0.50µm. Thus, if one jaw measures +15µin., the jaw
paired with it is not larger than +5µin. It would be preferable to use a jaw with a negative
measurement, if one was available. Pairing jaws is done to reduce the accumulation of errors
to the user. (By specification, jaws sold as pairs must have a combined size tolerance not
larger than ±40µin. or 1.0µm.)
For users ordering a single replacement jaw, the replacement will be within the normal tolerance
of ±20µin. or ±0.50µm.