Description
Product Overview
The Mitutoyo 368-162 Holtest is a three-point internal micrometer designed for the 8–10 mm bore range — the go-to tool when a bore gauge won’t cut it and you need repeatable, direct-reading accuracy inside small bores, reamed holes, and precision bushings. Unlike two-point bore gauges that require a master setting and can drift with jaw wear, the Holtest’s three-point contact system self-centres in the bore, eliminates the rocking error that plagues two-point designs, and delivers a direct micrometer reading without a separate comparator. For small-bore work where a tenth or two matters, this is the instrument you reach for.
- Three-point self-centring contact system — Three equally spaced, carbide-tipped measuring faces contact the bore simultaneously, automatically centring the instrument on the bore axis. This removes the operator skill variable that affects two-point gauges and eliminates cosine error, giving you a true diameter reading rather than a chord measurement.
- 0.001 mm graduation with ±0.003 mm accuracy — At this resolution, you can confidently verify H7 fits, check reamed holes to tolerance, and detect taper or bell-mouth across a bore depth. For small bores in the 8–10 mm range, where tolerances on interference and clearance fits are tight, that level of discrimination is what separates a Holtest from a standard bore gauge.
- Hardened and ground contact anvils — The measuring faces are carbide-tipped and precision ground, meaning they resist wear on repeated use in cast iron, steel, and hardened bores without introducing measurement error from face wear over time. A worn anvil is the silent killer of bore gauge accuracy — Mitutoyo’s material choice addresses this at the design level.
- Compact 8–10 mm range in a single head — This range covers common small-bore applications including small hydraulic cylinder bores, guide bush IDs, small bearing housings, and precision-drilled pilot holes. The range is narrow enough that the instrument maintains accuracy throughout — unlike extended-range bore gauges that compromise at the extremes.
- Ideal for — Checking reamed and bored holes to H6/H7 tolerance, verifying small bearing housing fits on a lathe or mill, inspecting guide bush and drill bush IDs, checking hydraulic valve body bores, and QC of small precision components on a surface plate or inspection bench.
Condition
New Old Stock (Unused / Factory Packaged)
This Holtest is exactly as it left the Mitutoyo factory — still sealed in its original factory packaging, with all papers and the original Mitutoyo calibration certificate included. The measuring faces, thimble, and body show no signs of use, contact wear, or handling marks. The carbide contact anvils will be in factory-ground condition with no pitting, flat spots, or scoring. The micrometer mechanism should operate with the smooth, consistent feel characteristic of a new Mitutoyo instrument. As this is New Old Stock rather than a freshly shipped production unit, it is good practice to verify the zero against a certified setting ring or gauge block stack before putting it into service — not because there is any reason to doubt the calibration, but because all precision instruments benefit from an incoming inspection check as a matter of sound metrology practice. The calibration certificate references an issue date of 22L06041E01; confirm this aligns with your calibration cycle requirements before use in a formal QC environment.
Included:
- 1 x Mitutoyo Holtest Three-Point Internal Micrometer, 368-162, 8–10 mm range, 0.001 mm graduation
- 1 x Original Mitutoyo hard case
- 1 x Mitutoyo calibration / inspection certificate (Issue No. 22L06041E01)
- 1 x Original warranty card / papers (保証書)
- 1 x Original factory accessories (as packaged)
Not included: Setting ring (not supplied by Mitutoyo as standard — a certified setting ring or gauge block stack should be sourced separately for in-house calibration verification).
Brand Information
Mitutoyo Corporation, founded in Japan in 1934, is the world’s largest manufacturer of precision measuring instruments and sits at the absolute top tier of the global metrology market — the benchmark against which other brands are measured, alongside Tesa (Switzerland) and Mahr (Germany). Mitutoyo instruments are manufactured in Japan under ISO 9000-series quality management systems with full national-standard traceability, and are the default choice in toolrooms, calibration labs, and inspection departments throughout Australian industry. When you put a Mitutoyo on the bench, you’re working with a tool that has earned its reputation on production floors, not just in catalogues.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model / Part Number | 368-162 |
| Type | Three-Point Internal Micrometer (Holtest) |
| Series | 368 Series |
| Measuring Range | 8–10 mm |
| Graduation / Resolution | 0.001 mm |
| Accuracy | ±0.003 mm |
| Reference Temperature | 20°C |
| Contact Points | Three-point, carbide-tipped, self-centring |
| Material / Construction | Hardened steel body, carbide measuring faces |
| Country of Origin | Japan |
| Condition | New Old Stock (Unused / Factory Packaged) |
| Included Items | Instrument, original hard case, calibration certificate, warranty / papers, original accessories |
| Not Included | Setting ring (not Mitutoyo standard supply) |
Keywords
Mitutoyo 368-162, Mitutoyo Holtest, Mitutoyo internal micrometer, three-point bore micrometer 8-10mm, small bore micrometer, Holtest bore gauge, internal mic toolroom, precision bore measurement, bore mic Australia, bearing housing gauge, reamed hole inspection, CNC inspection instrument
