Description
Product Overview
The Mitutoyo Holtest 368-107 is a two-point internal micrometer designed for precise bore measurement in the 25–30mm range. Unlike a telescoping gauge and outside mic combination, the Holtest gives you a direct reading inside the bore — no transfer step, no transferred error. For anyone checking bored holes, reamed bores, or bushings to tight tolerances on the bench or at the machine, this is the tool that removes a variable from your process.
- 0.001mm (1 micron) graduation: The thimble reads to one thou of a millimetre, putting it firmly in toolroom territory. When you’re verifying a bored hole to an H7 or similar fit tolerance, a coarser instrument simply won’t tell you what you need to know — this one will.
- Two-point contact measuring system: The spring-loaded, self-centring contact points locate consistently in the bore without rocking the tool to find the minimum reading the way a single-jaw telescoping gauge demands. Repeatability is the practical benefit — you get the same number, take after take.
- Ratchet-stop thimble: Consistent measuring force is built into the design. Operator-to-operator variation in applied force — a genuine source of error on cheaper instruments — is controlled by the ratchet mechanism, the same way it is on a standard outside micrometer.
- Compact, rigid body construction: The short measuring head accesses bores with limited depth — blind bores, short bushings, and bearing housings that a longer bore gauge or three-point mic can’t reach cleanly.
- Ideal for: Checking bored and reamed holes to tolerance in a lathe, mill, or jig boring context; verifying bearing housing bores; inspecting bushing and sleeve bores; confirming cylinder liner diameters in engine rebuilding; and production inspection of 25–30mm H-class fits.
Condition
Used (Good Condition / Pre-Owned, Functionally Sound)
The measuring surfaces and contact points are in good order — no visible damage, pitting, or wear to the carbide-tipped anvils that would compromise contact geometry. The thimble turns smoothly with no binding or play, and the ratchet stop engages cleanly. The barrel graduation and thimble markings are legible. The body carries the expected patina of a used precision instrument: light handling marks and surface wear consistent with careful workshop use, but nothing that affects the measuring function. As with any second-hand internal micrometer, verification against a setting ring in the 25–30mm range before returning the tool to service is strongly recommended — this confirms zero and identifies any drift from the instrument’s nominal accuracy. A suitable setting ring is listed separately by the seller and is not included with this listing.
Included:
- 1 x Mitutoyo Holtest Two-Point Internal Micrometer, 25–30mm, 0.001mm graduation (Series 368-107)
- Original Mitutoyo wooden storage case
- Original accessories (as pictured — wrench/spanner tool and spare contact set visible in case)
Not included: Setting ring (listed separately by seller — strongly recommended for zeroing and verification before use).
Brand Information
Mitutoyo Corporation is Japan’s largest manufacturer of precision measuring instruments and is widely regarded as the global benchmark in hand-tool metrology, sitting at the top tier of the market alongside Mahr, Tesa, and Starrett. Founded in 1934 in Kawasaki, Japan, Mitutoyo instruments are found in toolrooms, quality labs, and on machine shop benches worldwide because their manufacturing tolerances, calibration traceability, and long-term repeatability are genuinely consistent across the product range — not just on premium lines. Buying used Mitutoyo is a well-understood value proposition in the trade: the instruments hold their accuracy and their resale value in a way that lesser brands do not.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model / Part Number | Holtest 368-107 |
| Type | Two-Point Internal Micrometer (Holtest) |
| Series | 368 |
| Measuring Range | 25–30mm |
| Graduation / Resolution | 0.001mm (1 micron) |
| Accuracy | ±0.003mm (per Mitutoyo specification for this series — verify against current datasheet) |
| Measuring System | Two-point, self-centring, spring-loaded contact |
| Thimble / Force Control | Ratchet-stop thimble for consistent measuring force |
| Contact Point Material | Carbide-tipped |
| Country of Origin | Japan |
| Condition | Used — Good Condition |
| Included Items | Instrument, original wooden case, original accessories (spanner, spare contacts) |
| Not Included | Setting ring (listed separately) |
Keywords
Mitutoyo 368-107, Mitutoyo Holtest, Mitutoyo internal micrometer, bore mic 25-30mm, two-point internal micrometer, holtest bore gauge, internal micrometer toolroom, bore measurement micrometer, Mitutoyo bore gauge Australia, precision bore mic, bore gauge machining, internal micrometer metric
