Description
Product Overview
The Mitutoyo Holtest 368-143 is a three-point internal micrometer covering the 87–100mm range — a workhorse bore measuring tool built for toolrooms and production floors where a two-point bore mic or telescoping gauge simply won’t cut it. Three-point contact self-centres in the bore automatically, eliminating the rocking errors that plague two-anvil designs and giving you a repeatable reading without chasing the axis manually. This is the newer-style Mitutoyo Holtest body — cleaner ergonomics, tighter tolerances from the factory, and a thimble action that reflects the fit-and-finish you expect from Japanese metrology at this level.
- Three-point self-centring contact system — Unlike a two-anvil bore mic that requires the operator to find true diameter by rocking, the three-jaw contact system centralises itself in the bore. That means your reading is the actual diameter, not an approximation, which matters when you’re checking a bearing housing to H7 tolerance or verifying a cylinder liner after honing.
- 0.005mm graduation (5 micron resolution) — At this resolution you’re reading in single-digit microns across the thimble and vernier, which is enough precision to verify interference fits, check bores against a ground ring standard, and catch taper across a bore depth — all without needing a dedicated bench air gauge.
- 87–100mm measuring range — This range covers common engineering bores: 90mm and 95mm bearing housings, large hydraulic cylinder bores, gearbox and transmission cases, and larger lathe spindle bores. A single Holtest covers 13mm of range, so you’re not swapping anvils mid-job.
- Setting ring required for zeroing — A Holtest is zeroed against a calibrated ring gauge, not against itself. The seller notes a setting ring is available separately — if you don’t already have one for this range, factor that into your purchase. Without a traceable ring, you’re relying on the calibration certificate supplied, which is a reasonable starting point but not a substitute for a ground reference at your bench temperature.
- Ideal for — Checking bearing housing bores to H7/H6 fit, verifying honed cylinder bores, inspecting gearbox case bores, confirming large chuck register fits, and production inspection of 87–100mm bored components on a machining centre or horizontal borer.
Condition
Used (Like New / Well Cared For)
This Holtest presents in exceptional used condition — the seller describes it as like new and well cared for, and the visual evidence backs that up. The measuring faces and carbide contacts show no visible pitting, scoring, or wear that would affect measuring accuracy. The thimble rotates smoothly with no perceptible slop or drag, and the locking mechanism functions correctly. The newer-style Mitutoyo body is clean with no corrosion, deep scratches, or impact marks to the barrel or frame. Surface finish on the spindle and contact points appears consistent with a tool that has seen careful bench use rather than production floor abuse. The calibration certificate is included, providing a documented accuracy baseline — as with any used precision tool, we recommend verifying zero against a calibrated ring gauge at your working temperature before taking it into a critical tolerance job. A setting ring for this range is available separately from the seller if required.
Included:
- 1 x Mitutoyo Holtest Three-Point Internal Micrometer, 87–100mm, 0.005mm graduation, Model 368-143
- Original Mitutoyo wooden storage case
- Original papers / instruction manual
- Calibration certificate
- Original accessories (as supplied by Mitutoyo)
Not included: Setting ring gauge for 87–100mm range (available separately from the seller — enquire prior to purchase).
Brand Information
Mitutoyo Corporation, founded in Japan in 1934, is the largest dedicated precision measuring instrument manufacturer in the world and the benchmark against which all other metrology brands are measured — literally and figuratively. Their Holtest series sits at the top of the three-point internal micrometer market, in the same tier as Tesa and Mahr for bore measurement, and is the de facto standard in Australian toolrooms, automotive engine reconditioning shops, and aerospace subcontract facilities. Japanese manufacture, rigorous factory calibration, and a global service and calibration network make Mitutoyo instruments a sound long-term investment rather than a consumable.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model | 368-143 |
| Series | Holtest — Series 368 (Three-Point Internal Micrometer) |
| Type | Three-point self-centring internal micrometer |
| Measuring Range | 87–100mm |
| Graduation / Resolution | 0.005mm (5 micron) |
| Accuracy | ±0.003mm (per Mitutoyo specification for this series — verify against supplied calibration certificate) |
| Contact Points | Three-point carbide-tipped anvils |
| Zeroing Method | Setting ring gauge required (not included) |
| Country of Origin | Japan |
| Condition | Used — Like New / Well Cared For |
| Included Items | Instrument, original wooden case, papers/manual, calibration certificate, original accessories |
| Not Included | Setting ring gauge (available separately from seller) |
Keywords
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