Description
Product Overview
The OJIYAS 25mm Master Setting Ring is a precision metrology standard designed for calibrating and zeroing internal measuring instruments, such as 3-point Holtests, cylinder gauges, and bore gauges.
- Perfect Calibration: By providing an exact, known internal diameter of 25mm, this master ring allows you to set the highly accurate baseline required before measuring critical bores.
- Thermal Stability: OJIYAS master gauges undergo a professional sub-zero heat treatment process. This specialized tempering increases the steel’s hardness and wear resistance, while locking in its dimensional stability so the ring will not warp, shrink, or change size over its lifetime.
- Holtest Companion: An absolute necessity for any machinist using a 20-25mm or 25-30mm three-point internal micrometer (like a Mitutoyo Holtest). Without a master ring, it is impossible to truly verify the accuracy of a 3-point gauge.
Condition
Used (Possibly New Old Stock / Complete).
This setting ring is listed as used but is in excellent, possibly New Old Stock (NOS) condition.
- Included: Crucially, it comes safely stored in its original OJIYAS factory box and includes the original inspection/certificate papers. Having the factory paperwork guarantees its pedigree and provides the exact, certified deviation from 25.000mm, taking the guesswork out of your calibration.
Brand Information
OJIYAS (Ojiya Seiki Co., Ltd.) is a premier Japanese manufacturer specializing in limit gauges, master gauges, and high-precision inspection tools. Alongside giants like Mitutoyo, OJIYAS is considered top-tier in Japanese metrology. Their setting rings are trusted in aerospace and automotive inspection rooms globally for their repetitive consistency and extreme accuracy.+1
Specifications
| Feature | Specification |
| Brand | OJIYAS (Japan) |
| Type | Master Ring Gauge / Setting Ring |
| Size | 25mm |
| Application | Setting Holtests, Bore Gauges, Air Mics |
| Treatment | Sub-Zero Treated (High Stability) |
| Included | Setting Ring, Box, Inspection Papers |
Keywords
OJIYAS setting ring, 25mm master ring, 25mm ring gauge, holtest setting ring, bore gauge calibration, master gauge, Japanese metrology, machinist tools.





