Description
Product Overview
The Mitutoyo 141-206 is a tubular inside micrometer designed for measuring large bores, housings, and cylinder diameters across a wide 50–300mm range — a single instrument that replaces an entire set of fixed-range bore mics. With its modular extension rod system, this tool is built for the toolroom and the shop floor alike, delivering repeatable, high-confidence measurements in applications where a standard caliper or three-point bore mic simply won’t reach or won’t fit.
- 50–300mm measuring range via extension rods — the modular rod system lets you step through the full range without switching instruments. This matters when you’re chasing a precise fit on a large bearing housing or checking a bored-out casting — one tool, one reference datum, no accumulation of instrument-swap error.
- 0.01mm graduation — a single-thou resolution is appropriate for toolroom and general machining work on large-bore features, where fits and tolerances are rarely tighter than H7/g6. Enough precision to qualify a bore without over-engineering the instrument selection.
- Tubular micrometer head construction — the cylindrical head and extension rod geometry allows the anvil and spindle to reach into deep bores and narrow housings that a conventional inside mic or telescoping gauge can’t access cleanly, and without the operator-skill variability of a telescoping gauge feel.
- Mitutoyo extension rod system (included) — the kit ships with multiple extension rods in original wrapping, allowing the range to be built up incrementally. Important note: the extension rod thread is left-hand on one end — refer to the included instruction card before assembly to avoid cross-threading or unintended detachment during measurement.
- Ideal for — qualifying large bearing seats and housings, checking bored-out lathe and mill work, measuring hydraulic cylinder bores, verifying cast iron housing diameters on heavy equipment, and incoming inspection of large-bore components against engineering drawings.
Condition
Used (Like New / Virtually Unused)
This instrument presents in exceptional condition consistent with the seller’s disclosure — used approximately three times and stored in its original case. The micrometer head shows no meaningful wear on the thimble, sleeve graduations, or spindle faces. The measuring anvils are clean and free of the pitting, raised burrs, or wear flats that typically appear on a worked instrument. The chrome surfaces retain their original factory finish with no pitting, scoring, or corrosion — just the very lightest handling marks that would be invisible in normal use. Critically, the precision contact surfaces — spindle face and anvil — are undamaged, which is the only place condition truly matters for measurement integrity.
Of the extension rod packets, the seller confirms only two have been opened; the remainder are still in original factory wrapping, visible in the photograph. All components appear to be present and accounted for. As with any used precision instrument, even one in this condition, we recommend zeroing the head against a known standard or calibrated ring gauge at your working range before taking it to drawing for the first time — not because there’s any reason to suspect drift, but because that’s sound toolroom practice regardless of condition or age.
Included
- 1 x Mitutoyo 141-206 Tubular Inside Micrometer, 50–300mm, 0.01mm graduation
- Extension rods (full set — majority in original unopened factory wrapping)
- Original moulded plastic carry case
- Original instruction / assembly card (English and Japanese, visible in photograph)
- Original accessories as supplied by Mitutoyo
Not Included
- Setting ring / calibration master (not standard with this model — source separately if formal calibration records are required)
Brand Information
Mitutoyo Corporation, founded in Japan in 1934, is the benchmark against which most other precision measuring instrument manufacturers are judged. Their products are manufactured to exacting tolerances in purpose-built metrology facilities and are found in toolrooms, quality labs, and on machine shop floors across every serious manufacturing nation. In the metrology market, Mitutoyo sits alongside Mahr and Tesa at the top tier — above most Chinese and Taiwanese production brands, and on par with the best European alternatives in terms of calibration traceability, surface finish quality, and long-term dimensional stability. For Australian machinists, Mitutoyo instruments are widely supported with local calibration services through accredited labs.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model | 141-206 |
| Type | Tubular Inside Micrometer (Extension Rod Type) |
| Measuring Range | 50–300mm |
| Graduation / Resolution | 0.01mm |
| Accuracy | ±0.006mm (refer to Mitutoyo specification sheet for full range accuracy — verify against current datasheet) |
| Construction | Tubular micrometer head with modular extension rod system; hardened and ground contact surfaces |
| Extension Rod Thread Note | Left-hand thread on rod end D — refer to instruction card before assembly |
| Country of Origin | Japan |
| Condition | Used (Like New / Virtually Unused — approx. 3 uses) |
| Included Items | Micrometer head, extension rod set (majority unopened), original case, instruction card, original accessories |
| Not Included | Calibration / setting ring |
Keywords
Mitutoyo 141-206, Mitutoyo tubular inside micrometer, inside micrometer 50-300mm, large bore micrometer, extension rod inside mic, bore mic 300mm, Mitutoyo inside mic, toolroom micrometer, bore measurement instrument, inside micrometer Australia, large bore measurement, cylinder bore micrometer
