Product Overview
Measuring gear tooth thickness, spline roots, or the wall of a thin-walled tube with a standard flat-anvil micrometer is a compromise at best — the contact geometry is wrong, and you’re reading a number that reflects geometry rather than the actual material thickness you care about. The disc micrometer exists specifically to solve this: its large-diameter, thin disc anvil and disc spindle face reach into grooves, recesses, and root profiles where a standard micrometer simply can’t land flat. This Mitutoyo 25–50 mm disc micrometer gives you a genuine 0.01 mm graduation across that range with the contact geometry engineered for the job — and it presents in like-new condition that suggests it saw very light bench use, if any at all.
- Disc-type anvil and spindle faces — The thin disc contacts allow the micrometer to reach into gear root circles, spline grooves, and keyways without the frame fouling on adjacent surfaces. This is the entire reason the tool exists; a standard flat anvil would bridge across a groove and give you a false reading.
- 25–50 mm measuring range at 0.01 mm graduation — Covers a practical mid-range that aligns with common gear module and shaft dimensions encountered in production and toolroom work. The 0.01 mm (10 µm) graduation is sufficient for gear inspection to DIN/ISO quality grades and wall-thickness checks on precision-turned components.
- Mitutoyo precision ground spindle and anvil — The measuring faces on a disc mic take more incidental lateral load than a standard micrometer. Mitutoyo’s ground and lapped spindle thread and measuring faces maintain accuracy under that load, which is where cheaper disc mics tend to drift.
- Setting standard required for zero verification — This range does not self-zero at closure; a 25 mm setting standard (or Mitutoyo setting ring) is required to establish the datum before use. Factor this in if you don’t already have one on the bench.
- Ideal for — Gear tooth thickness and root measurement, spline and serration inspection, thin-walled tube and bush wall measurement, keyway depth verification on shafts, and any groove or recess geometry where disc contact is necessary.
Condition
Used (Like New / Light Bench Use)
Visually, this micrometer presents extremely well. The frame’s dark enamel finish retains its original lustre with no chips, gouges, or heavy contact marks — the textured panels show no wear beyond normal handling. The thimble knurl is sharp and crisp, the lock nut operates cleanly, and the ratchet stop engages with the tactile consistency you’d expect from a tool that hasn’t seen sustained production use. The disc anvil and disc spindle faces appear clean and undamaged under inspection — no visible pitting, scoring, or rollover on the disc edges, which are the first surfaces to show abuse on this type of micrometer. Spindle movement is smooth throughout the range with no perceptible backlash or tight spots. As with any used precision instrument, zeroing against a calibrated 25 mm setting standard or having the unit checked against a master before critical production work is standard practice and strongly recommended — this is not a reflection of any observed fault, but simply correct metrology discipline for any second-hand mic entering a quality chain.
Included:
- 1 x Mitutoyo Disc Micrometer, 25–50 mm, 0.01 mm graduation
Not included: Original storage case, 25 mm setting standard / setting ring (required for zeroing this range).
Brand Information
Mitutoyo Corporation, founded in Japan in 1934, is the benchmark against which virtually all other precision measuring instrument manufacturers are assessed. Their micrometers, vernier tools, and CMM systems are found in aerospace, automotive, defence, and toolroom environments worldwide precisely because their manufacturing tolerances, calibration traceability, and long-term dimensional stability are consistently verifiable. In the micrometer market specifically, Mitutoyo sits at the top tier alongside Mahr and Starrett — tools that hold their accuracy over decades of shop-floor use and for which calibration services, setting standards, and replacement parts remain commercially available in Australia.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Type | Disc Micrometer (Outside) |
| Measuring Range | 25–50 mm |
| Graduation / Resolution | 0.01 mm |
| Accuracy | ±0.004 mm (as per Mitutoyo specification for this range) |
| Disc Anvil / Spindle Face Diameter | Approx. 20 mm (thin disc type — verify against Mitutoyo Series 169 documentation) |
| Frame Construction | Enamel-coated steel frame, precision ground spindle |
| Thimble / Locking | Ratchet stop thimble, lock nut fitted |
| Country of Origin | Japan |
| Condition | Used (Like New / Light Bench Use) |
| Included Items | Micrometer only |
| Not Included | Storage case, 25 mm setting standard |
Note: Confirm exact series number (likely Mitutoyo Series 169) against Mitutoyo AU documentation to verify full accuracy specification and disc face diameter prior to publication.
Keywords
Mitutoyo disc micrometer, Mitutoyo 25-50mm micrometer, disc micrometer outside, gear tooth micrometer, Mitutoyo Series 169, spline measurement micrometer, groove micrometer toolroom, precision outside micrometer Australia, disc anvil micrometer, thin wall measurement micrometer, Mitutoyo micrometer used, machinist micrometer 50mm
