Description
Condition
New old stock (NOS). Light patina on the top and bottom faces from storage. Bore is clean and spotless, suitable as a master for checking.
Product Use / Description
Precision 25.5 mm set ring (master ring gauge) for zero-setting and verifying three-point internal micrometers (Holtest-type) and other bore measuring tools. Use as a stable reference to calibrate 20–30 mm class internal mics and to perform quick repeat checks during inspection.
Brand
SK (Japan)
Features / Specs
| Item | Detail |
|---|---|
| Type | Master set ring gauge |
| Nominal size | Ø25.5 mm |
| Intended use | Setting/calibrating 3-point hole micrometers and comparative bore gauges |
| Finish | Lapped bore; outer faces show light storage patina |
| Accuracy | Working master (grade not marked on item) |
| Compatibility | Ideal companion for 20–30 mm internal micrometers (Holtest-type) |
| Included | Set ring only (no certificate or case unless shown in photos) |
| Condition notes | NOS; cosmetic patina externally; bore is clean and to size |
