Description
Mitutoyo 35mm Setting Ring — 177-140
A Mitutoyo setting ring is one of those toolroom essentials that quietly underpins accurate bore measurement across the whole shop. This 177-140 is a precision-ground 35.002mm internal diameter reference standard, used to zero and verify bore gauges, internal micrometers, and plug gauges before you commit to a critical measurement. If your bore mic isn’t zeroed against a traceable ground reference, you’re guessing — this ring removes that variable entirely.
- 35.002mm precision-ground internal diameter — The bore diameter is lapped and ground to a certified nominal size, giving you a stable, repeatable master reference. That fractional deviation from a round number (35.002mm rather than 35.000mm) is the actual measured and certified size of this specific ring — what matters is that it’s known, consistent, and marked on the face so you can account for it when zeroing your instrument.
- Hardened steel construction with a stable ground bore — Setting rings are made from hardened tool steel and finish-ground on the bore surface. Hardness means the reference surface resists wear from repeated gauge insertion; a worn bore surface in a setting ring is a slow-moving source of systematic error, so material quality here is directly tied to long-term measurement integrity.
- Direct face-marking of the certified size — The nominal size (35.002mm) and the Mitutoyo brand are engraved directly on the face of the ring, as visible in the photograph. This means you always know exactly what you’re zeroing to — no guessing, no lost paperwork mid-shift.
- Compatible with bore gauges, internal micrometers, and air gauges — Use this ring to zero a Mitutoyo or third-party bore gauge, set an internal micrometer, verify a plug gauge, or establish a datum for an air gauge system. It is a passive reference standard — no instrument is included or required to use the ring itself.
- Ideal for — zeroing bore gauges prior to measuring bearing housings, hydraulic cylinder bores, and gearbox bores; verifying internal micrometer zero-set on a surface plate; calibration checks on plug gauges; and incoming inspection of machined bores in a quality or toolroom environment.
Condition
Used (Good Condition / Surface Patina, Bore Reference Surface Intact)
The bore reference surface — which is the only surface that matters functionally — appears intact and free from visible damage, scoring, or deformation based on inspection of the available photographs. The internal diameter reads 35.002mm as marked. The external faces and outer diameter show the expected patina and minor surface marks consistent with toolroom use and storage; there are also a small number of light rust spots visible on the flat face of the ring, as clearly shown in the image. These are surface-level only and are located on the non-critical outer face, not within the precision-ground bore itself. They do not affect the bore geometry or the ring’s function as a zeroing reference. As with any used setting ring, buyers should verify the bore diameter against a calibrated instrument or send the ring for re-certification if traceable accuracy documentation is required for a quality system. For general toolroom zeroing and bore gauge setup, this ring will perform as intended.
Included:
- 1 x Mitutoyo 35.002mm Setting Ring, Series 177-140
- 1 x Original Mitutoyo cardboard box with foam insert
Not included: Certificate of calibration / inspection report (no current traceable cert supplied — recommend independent re-certification if required for a documented quality system).
Brand Information
Mitutoyo is a Japanese precision instrument manufacturer founded in 1934 and is widely regarded as the global benchmark in metrology tooling — sitting in the same tier as Tesa, Mahr, and Starrett, and consistently above the mid-market field in terms of manufacturing tolerances and long-term stability. Their setting rings, bore gauges, micrometers, and surface plates are found on the benches of aerospace subcontractors, automotive production lines, and quality-critical toolrooms worldwide. Japanese origin is a genuine selling point here: Mitutoyo’s manufacturing tolerances and quality control are not marketing language — they’re the reason the brand commands the price it does on the used market.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model / Part Number | 177-140 |
| Type | Setting Ring (Internal Diameter Reference Standard) |
| Series | 177 |
| Nominal Internal Diameter | 35.002mm (as marked on face) |
| Graduation / Resolution | N/A — passive reference standard |
| Accuracy | Ground and lapped to Mitutoyo series tolerance (re-certification recommended for documented QA use) |
| Material / Construction | Hardened tool steel, precision-ground bore |
| Country of Origin | Japan |
| Condition | Used — Good Condition (surface patina and minor face rust spots; bore surface intact) |
| Included Items | Setting ring, original Mitutoyo box with foam insert |
| Not Included | Calibration certificate |
Keywords
Mitutoyo 177-140, Mitutoyo setting ring, Mitutoyo bore gauge reference, 35mm setting ring, internal diameter setting ring, bore gauge zeroing ring, toolroom reference standard, precision setting ring Australia, bore mic master ring, internal micrometer setting standard, Mitutoyo metrology toolroom, ground bore reference ring
