Description
Product Overview
When you’re measuring a large bore — a cylinder liner, a bearing housing, a deep counterbore — a standard inside mic or bore gauge simply won’t reach. You need a telescoping rod system that can span the gap accurately, hold a repeatable reading, and give you a real micrometer thimble to read from, not a dial you’re second-guessing under workshop lighting. That’s the exact problem the Mitutoyo 137-104 solves: a full 50–1000mm inside micrometer set with interchangeable extension rods that lets you walk up to any large internal diameter, lock a measurement, and read it with the same confidence you’d expect from a bench micrometer. This set is used and fully serviceable, with all rods accounted for and accuracy confirmed — a genuine shop-floor workhorse at a fraction of new price.
- 50–1000mm measuring range via interchangeable extension rods — The modular rod system is what makes this set genuinely versatile. Rather than buying multiple dedicated instruments, you build up the stack to suit the bore. That 950mm of coverage handles everything from medium-sized hydraulic cylinder bores to large pump housings in a single instrument set.
- Micrometer head with 0.01mm graduation — Unlike telescoping gauges that only transfer a size, this instrument reads directly off a calibrated thimble. You get a real measurement, not a comparative one. On large bores where a tenth of a millimetre matters — bearing fits, sleeve fits, liner clearances — that direct readout removes a transfer step and the error that comes with it.
- Mitutoyo build quality — ground measuring faces and hardened spindle — The anvil and spindle contact faces are precision ground and hardened. On an inside mic working at extended rod lengths, any slop in the contact surfaces or spindle thread compounds across the stack. Mitutoyo’s manufacturing tolerances keep that error controlled.
- Compatibility — Rods are proprietary Mitutoyo 137-series extensions. Setting rings or a known-good reference bore are recommended for zeroing at each rod combination — these are not included and should be sourced separately if you don’t already have them in your toolroom.
- Ideal for — Measuring large cylinder bores, hydraulic ram housings, bearing housing bores, large lathe chuck register fits, pump and compressor component inspection, and any internal diameter work beyond the reach of a standard three-point bore mic.
Condition
Used (Good Condition / All rods opened and used, case exterior heavily soiled)
The micrometer head functions correctly — the thimble turns smoothly with no detectable backlash or binding, the locking mechanism holds, and the spindle thread is in good order. All extension rods are present and accounted for, and the seller confirms the set is still accurate and perfectly serviceable after use. The measuring faces and rod mating surfaces show normal wear consistent with a used precision instrument — no deep scoring or impact damage observed. The original foam-lined case holds all components securely in their correct cut-outs, which is a genuine plus: rod sets that have been stored loose or in wrong positions often suffer thread damage at the coupling joints. The case exterior, however, is described as very dirty — this is a cosmetic issue only and has no bearing whatsoever on the instrument’s measuring function. As is standard practice with any used inside mic set, it is strongly recommended that you verify zero at each rod combination against a certified setting ring or a known master bore before putting this instrument into production use — this is good metrology practice regardless of the instrument’s age or source.
Included:
- 1 x Mitutoyo Inside Micrometer Set, Model 137-104, 50–1000mm range
- Full set of interchangeable extension rods (all opened and used)
- Micrometer head with thimble
- Original foam-lined plastic case
Not included: Setting rings / reference masters (recommended for zeroing — not supplied), calibration certificate.
Brand Information
Mitutoyo is Japan’s largest manufacturer of precision measuring instruments and sits at the top tier of the global metrology market alongside Mahr, Tesa, and Starrett. Founded in 1934 and headquartered in Kawasaki, Mitutoyo instruments are manufactured to exacting Japanese Industrial Standards and are the reference-grade choice in toolrooms, quality labs, and on machine shop floors worldwide. In the Australian trade, Mitutoyo is the benchmark brand against which other measuring instruments are compared — their micrometers, bore gauges, and height gauges are standard issue in precision engineering shops across the country.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model | 137-104 |
| Type | Inside Micrometer Set (Interchangeable Rod Type) |
| Measuring Range | 50–1000mm |
| Graduation / Resolution | 0.01mm |
| Accuracy | Refer to Mitutoyo 137-series specification sheet (verify against setting ring before use) |
| Rod System | Interchangeable extension rods, proprietary Mitutoyo 137-series |
| Material / Construction | Hardened and ground steel measuring faces; hardened spindle |
| Country of Origin | Japan |
| Condition | Used — Good. All rods present and used. Set confirmed accurate and serviceable. Case exterior soiled (cosmetic only). |
| Included Items | Full rod set, micrometer head, original foam-lined case |
| Not Included | Setting rings, calibration certificate |
Keywords
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