Description
Product Overview
The Mitutoyo Holtest 368-140 is a three-point internal micrometer covering the 50–63mm bore range — a workhorse instrument for anyone who needs repeatable, accurate bore measurement without the setup fuss of a two-point bore gauge and setting ring. Unlike traditional two-anvil bore mics, the Holtest’s three-contact design self-centres in the bore, eliminating the rocking technique and reducing operator-induced error. If you’re checking cylinder bores, housing fits, or bushing bores to tight tolerances, this is the instrument that earns its place on the bench.
- Three-point self-centring contact system — The tri-anvil head automatically aligns to the bore centreline on insertion, removing the skilled rocking motion required with a two-anvil mic. That means consistent readings between operators and far less chance of measuring a chord instead of a true diameter — critical when you’re holding a fit to a few thou.
- 0.001mm graduation on a direct-reading thimble — The Holtest reads directly off the sleeve and thimble without conversion or interpolation. At 0.001mm resolution across the full 50–63mm range, you’re equipped to verify H7/p6 interference fits and similar close-tolerance work with confidence.
- Hardened and ground measuring contacts — Mitutoyo’s contacts are manufactured to tight geometric tolerances and hardened for wear resistance. The spherical contact points minimise cosine error when the tool isn’t perfectly perpendicular to the bore axis — an honest safety net in production environments.
- Original Mitutoyo wooden case with accessories included — Ships with the original wooden storage box, spanner wrench, and documentation. Proper storage keeps the measuring faces protected and the instrument ready for calibration checks — not rattling around a drawer.
- Ideal for — checking bored housing fits for bearings and bushings, verifying cylinder liner bores, inspecting hydraulic cylinder bores, checking spindle housing bores on lathes and mills, and qualifying bored parts on a machining centre where a two-point gauge would require a master setting ring every session.
Condition
Used (Like New / Minimal Use)
This Holtest presents exceptionally well for a used instrument. The thimble rotates smoothly through its full range with no perceptible backlash or roughness, and the tri-anvil head shows no visible wear, scoring, or corrosion on the contact points — the ground reference surfaces that actually determine your measurement. The barrel and sleeve graduations are clean and fully legible. The body finish retains the vast majority of its original surface with only the lightest handling marks consistent with an instrument that’s been handled carefully and stored properly rather than left on a swarf-covered bench. There is no visible damage, pitting, or impact marking reported by the seller, and nothing visible in inspection imagery that would suggest otherwise. As with any used precision instrument — regardless of cosmetic condition — we recommend verifying zero against a certified ring gauge or a known bore standard before putting it into production work. That’s simply good metrology practice, not a reflection of any functional concern with this specific tool.
Included
- 1 x Mitutoyo Holtest Three-Point Internal Micrometer, 50–63mm, 0.001mm graduation (Series 368-140)
- 1 x Original Mitutoyo wooden storage case
- 1 x Spanner wrench / setting tool (as supplied originally)
- 1 x Original documentation / papers
Not Included
- Setting ring gauge (not supplied by Mitutoyo as standard — purchase separately if calibration traceability is required)
Brand Information
Mitutoyo Corporation, founded in Japan in 1934, is widely regarded as the global benchmark in dimensional metrology — sitting at the top tier of the market alongside Mahr, Tesa, and Starrett, and a clear step above general industrial brands in terms of manufacturing consistency and long-term accuracy retention. Their instruments are manufactured to Japanese Industrial Standards (JIS) and many models carry JCSS-traceable calibration options, making them acceptable for ISO 9001 and AS/NZS quality system environments. For Australian toolrooms, Mitutoyo is the name you calibrate your other gauges against.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model | 368-140 |
| Type | Holtest — Three-Point Internal Micrometer |
| Series | 368 |
| Measuring Range | 50–63mm |
| Graduation / Resolution | 0.001mm |
| Accuracy | ±0.003mm (refer to Mitutoyo specification sheet for full accuracy statement) |
| Contact System | Three-point self-centring tri-anvil head |
| Contact Point Material | Hardened steel (carbide-tipped on select variants — verify on instrument) |
| Display Type | Analogue — sleeve and thimble (vernier) |
| Country of Origin | Japan |
| Condition | Used (Like New / Minimal Use) |
| Included Items | Instrument, original wooden case, spanner wrench, original documentation |
| Not Included | Setting ring gauge |
Keywords
Mitutoyo 368-140, Mitutoyo Holtest, Mitutoyo internal micrometer, three-point bore micrometer 50-63mm, bore mic 50mm, holtest bore gauge, internal micrometer toolroom, precision bore measurement Australia, bore gauge machining centre, Mitutoyo Series 368, tri-anvil internal micrometer, used Mitutoyo bore mic
