Description
Product Overview
This Mitutoyo 133-902 inside micrometer set covers the full 50–300mm range in 25mm steps, giving you a comprehensive bore measurement solution straight out of the one case. Whether you’re checking bored housings, cylinder bores, or large-diameter turned fits on the lathe, this set puts Japanese toolroom accuracy in your hands without the need to swap instrument types mid-job. Each micrometer in the set reads to 0.01mm graduation — enough resolution for the vast majority of precision fitting and inspection work a machinist or toolmaker will encounter on the bench.
- 0.01mm graduation across the full 50–300mm range — At one hundredth of a millimetre per division, these instruments resolve well within typical H7/p6 and similar interference and clearance fits. For bore-to-shaft matching, that resolution is the difference between a confident fit and a guess.
- 25mm step increments from 50mm to 300mm — Each micrometer spans only 25mm, which keeps the measuring faces nearly parallel throughout the range. Wider-spanning instruments introduce more angular error at the extremes; the 25mm steps here maintain consistent measuring geometry and contact integrity across every size in the set.
- Mitutoyo tubular inside micrometer design — The tubular body extends via a screw mechanism at the thimble end with fixed measuring faces (anvils) at each tip. This direct-contact design means no slip joints or interchangeable rods to introduce stack-up error — each instrument in the set is a self-contained, ground-reference unit.
- Original Mitutoyo carry case included — The fitted foam case keeps each mic seated and protected from contact damage. In a set like this, individual instruments rattling loose means dinged anvil faces and lost zero — the case is part of the calibration discipline, not just a convenience.
- Ideal for — checking bored housing diameters on mill or lathe, measuring cylinder liner bores, inspecting large-diameter bearing housings, verifying boring head passes during roughing and finishing cycles, and confirming bore dimensions against a setting ring or bore gauge master prior to final fit.
Condition
Used (Good Condition / Complete Set, One Replacement Unit)
The set is complete across the full 50–300mm range with all eight instruments present and accounted for in the original Mitutoyo fitted case. The 200–225mm micrometer has been replaced with an older Mitutoyo unit — visible in the image by the different body finish and the earlier-generation label style — however it remains a genuine Mitutoyo instrument of the same type and graduation. Mechanically, the instruments present well: thimble action is smooth without noticeable slop or binding, and the measuring faces show no obvious pitting or impact damage to the anvil surfaces. General patina and light handling marks consistent with workshop use are present on the bodies — nothing that affects measurement function. As with any used precision instrument, particularly inside mics that rely on accurate zero-setting, the buyer should verify each unit against a calibrated ring gauge or bore gauge master at the relevant size before putting them to work. The 200–225mm replacement unit in particular should be checked for zero agreement with the remainder of the set.
Included:
- 1 x Mitutoyo 133-902 Inside Micrometer Set, 50–300mm, 0.01mm graduation (8 instruments)
- 1 x Original Mitutoyo fitted foam carry case
- Original accessories as supplied with set
Not included: Setting rings / bore gauge masters for zero verification (recommended for calibration check prior to use).
Brand Information
Mitutoyo Corporation is Japan’s largest manufacturer of precision measuring instruments and one of the most respected metrology brands in the world, with a history dating back to 1934. Their instruments are manufactured in Japan to exacting tolerances and sit at the top tier of production metrology tooling — consistently benchmarked alongside Mahr, Tesa, and Starrett for accuracy, repeatability, and build longevity. In the Australian toolroom and machining centre environment, Mitutoyo is effectively the benchmark brand: widely supported, well-understood by tradespeople, and retaining strong resale and calibration value throughout their service life.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model / Series | 133-902 |
| Type | Tubular Inside Micrometer Set |
| Measuring Range | 50–300mm (8 instruments in 25mm steps) |
| Individual Instrument Steps | 50–75, 75–100, 100–125, 125–150, 150–175, 175–200, 200–225, 225–250, 250–275, 275–300mm (set covers full range) |
| Graduation / Resolution | 0.01mm |
| Accuracy | Refer to Mitutoyo 133-series specifications; verify against calibrated ring gauges prior to critical use |
| Construction | Hardened steel measuring faces, tubular body with knurled thimble |
| Country of Origin | Japan |
| Condition | Used (Good Condition) — complete set; 200–225mm unit is an older Mitutoyo replacement |
| Included Items | Full set of instruments (50–300mm), original Mitutoyo fitted foam case, original accessories |
| Not Included | Setting rings / calibration masters |
Keywords
Mitutoyo 133-902, Mitutoyo inside micrometer set, inside micrometer 50-300mm, tubular bore micrometer, bore mic set, Mitutoyo bore gauge, inside mic 300mm, precision bore measurement, toolroom micrometer set, machinist bore measuring tools, cylinder bore micrometer, Japanese inside micrometer
