Gage Blocks and Accessories Technical Data
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.
- Permanent comparisons with master gages, interferometrically verified by the Physikalish-Technischen Bundesanstalt (PTB), and
- Interferometric examination in KOBA's environmentally controlled laboratories
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 which combines natural and artificial aging. Grade accuracy should be selected according to the intended purpose:
- Grade K: suitable as the most accurate material measure with regard to length and for checking gage blocks of lower grades. Grade K gage blocks can be marked with 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: used for checking gages or setting measurement instruments
- Grade 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, and for an additional charge, we can supply a certificate of the true size value of the PTB
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.
Gage Block Accuracy
| Nominal Length Range, mm | Grade K | Grade 0 | Grade 1 | Grade 2 | ||||
| Limit deviations of length at any point from nominal length | Tolerance for the variation in length | Limit deviations of length at any point from nominal length | Tolerance for the variation in length | Limit deviations of length at any point from nominal length | Tolerance for the variation in length | Limit deviations of length at any point from nominal length | Tolerance for the variation in length | |
| ± te µm | tv µm | ± te µm | tv µm | ± te µm | tv µm | ± te µm | tv µm | |
| from 0.5-10 | 0.2 | 0.05 | 0.12 | 0.1 | 0.2 | 0.16 | 0.45 | 0.3 |
| from 10-25 | 0.3 | 0.05 | 0.14 | 0.1 | 0.3 | 0.16 | 0.6 | 0.3 |
| from 25-50 | 0.4 | 0.06 | 0.2 | 0.1 | 0.4 | 0.18 | 0.8 | 0.3 |
| from 50-75 | 0.5 | 0.06 | 0.25 | 0.12 | 0.5 | 0.18 | 1.0 | 0.35 |
| from 75-100 | 0.6 | 0.07 | 0.3 | 0.12 | 0.6 | 0.2 | 1.2 | 0.35 |
| from 100-150 | 0.8 | 0.08 | 0.4 | 0.14 | 0.8 | 0.2 | 1.6 | 0.4 |
| from 150-200 | 1.0 | 0.09 | 0.5 | 0.16 | 1.0 | 0.25 | 2.0 | 0.4 |
| from 200-250 | 1.2 | 0.1 | 0.6 | 0.16 | 1.2 | 0.25 | 2.4 | 0.45 |
| from 250-300 | 1.4 | 0.1 | 0.7 | 0.18 | 1.4 | 0.25 | 2.8 | 0.5 |
| from 300-400 | 1.8 | 0.12 | 0.9 | 0.2 | 1.8 | 0.3 | 3.6 | 0.5 |
| from 400-500 | 2.2 | 0.14 | 1.1 | 0.25 | 2.2 | 0.35 | 4.4 | 0.6 |
| from 500-600 | 2.6 | 0.16 | 1.3 | 0.25 | 2.6 | 0.4 | 5.0 | 0.7 |
| from 600-700 | 3.0 | 0.18 | 1.5 | 0.3 | 3.0 | 0.45 | 6.0 | 0.7 |
| from 700-800 | 3.4 | 0.2 | 1.7 | 0.3 | 3.4 | 0.5 | 6.5 | 0.8 |
| from 800-900 | 3.8 | 0.2 | 1.9 | 0.35 | 3.8 | 0.5 | 7.5 | 0.9 |
| from 900-1000 | 4.2 | 0.25 | 2.0 | 0.4 | 4.2 | 0.6 | 8.0 | 2.0 |
| Limit deviations of the length "te" at any point and tolerances of variation in length "tv" to EN ISO 3650:1998, for DIN 861 | ||||||||
Applicable SIC Codes: 3423, 3545, 5049, 5084 Applicable NAICS Codes: 332212, 333515, 423490, 423830