| Accuracy KOBA Gage Blocks are manufactured and
verified to the specifications of EN ISO 3650. As tolerances are kept to a minimum by
internal standards, every gage block is guaranteed to be within the limits stipulated.
The high level of accuracy and the
reliability of the measuring results are guaranteed by two separate comparisons to the
internationally fixed unit of length by means of a wave length.
1. Permanent comparisons with master
gages, interferometrically verified by the Physikalish-Technischen Bundesanstalt (PTB).
2. Interferometric examination in
KOBA's environmentally controlled laboratories.
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Tolerance
ranges of the individual grades, within the limits of which the actual size is guaranteed,
are indicated in the table below. The durability of gage blocks is achieved by a special
process developed by KOBA combining natural and artificial aging. The grade of accuracy should be selected
according to the intended purpose:
Grade K: Gage blocks of grade
K are suitable as the most accurate material measure with regard to length and for
checking gage blocks of lower grades.
Gage blocks of grade K can be marked
with a serial number and supplied with a DKD calibration certificate which indicates the
deviation from the nominal size of each gage block.
Grade 0: Used as master gages
for all accurate measurements of length, for checking all gage blocks in use, for final
inspection, or for setting accurate measurement instruments.
Grade 1: For checking gages
or setting measurement instruments.
Gage 2: Used as a standard
for setting or as a workshop gage for the manufacture of jigs and gages, as well as for
machines and instruments.
Upon request, we can supply a
certificate of the true size value of the PTB for an additional charge.
In most facilities the use of one
grade only is insufficient as the accuracy requirements vary between individual
departments and manufacturing stages. If, as a result of frequent use, Grade 0 gage blocks
are no longer accurate enough for inspection, they can be passed on to a department or
workshop where the demands on accuracy are accordingly lower -- however, we recommend
having them inspected beforehand. |
