Description
This listing is for a used Mitutoyo 50-300 mm inside micrometer, model 137-102, offered in its original wooden storage box. The instrument has been inspected and remains fully operational, though the internal foam insert in the box has deteriorated — the mic itself is intact, functional, and ready for precise internal diameter measurements. This unit is ideal for machinists, toolrooms, and precision metrology environments looking for high-quality internal measurement instrumentation at a lower cost than new.
Mitutoyo’s Series 137 “extension rod type” inside micrometers are well regarded in the machining and metrology community for their modular rod system, repeatability, and long-term stability under regular workshop usage.
Below is the technical specification and features summary, with explicit note on condition.
Key Features & Technical Specifications
| Parameter | Detail |
|---|---|
| Condition | Used, fully functional, calibration not certified (sold “as is”) |
| Measuring Range | 50 mm to 300 mm |
| Graduation / Resolution | 0.01 mm (10 µm) |
| Micrometer Head Travel / Stroke | 13 mm |
| Extension Rods Supplied | 5 rods: 13 mm, 25 mm, 50 mm (×2), 100 mm |
| Accuracy / Tolerance | ±(3 + n + L/50) µm (where n = number of rods, L = measurement length in mm) |
| Measuring Face Material | Hardened steel (non-carbide version) |
| Spindle / Thread | Standard micrometer spindle, pitch typical for Mitutoyo micrometer heads |
| Weight / Mass | ~305 g (main body |
| Packaging / Storage | Original wooden box (foam insert degraded) |
| Accessories / Extras | Internal rods, original storage box; no calibration certificate or setting ring included |
| Brand / Series | Mitutoyo, Series 137 extension rod tubular inside micrometer |
Application & Use Cases (SEO Keywords for Machinists / Precision Work)
- Ideal for internal diameter verification (ID measurement) in precision machining, bore gauging, and quality control.
- Useful in toolrooms, fixture manufacturing, and when bridging measurement spans through rod combinations.
- Supports modular measurement setups for internal bores, cylinders, sleeves, and machined holes from 50 mm up to 300 mm.
- Compatible with standard measurement protocols; can be cross-checked with setting rings or gauge blocks in metrology labs.
- A cost-effective alternative for shops needing a mid-range inside micrometer without paying full new prices.
Condition Notes & Buyer Guidance (Important for Used Equipment)
- This is a used instrument; while fully functional, it is sold without a fresh calibration certificate. Buyers should consider verifying accuracy before mission-critical use.
- The wooden box’s foam insert has degraded; users should plan alternate packaging or foam replacement for safe transport.
- All rods and micrometer head bodies show normal wear from workshop use (light surface patina might be present), but no damage or deformation affecting measurement integrity.
- It is recommended to check zero setting at several rod configurations and verify with known standards before use in precision tasks.
