Description
Product Overview
The Mitutoyo 368-141 Holtest is a three-point internal micrometer covering the 62–75mm bore range — a workhorse instrument for any toolroom or production floor where accurate bore measurement is non-negotiable. Unlike a two-point bore gauge that relies on a separate dial indicator and master setting, the Holtest reads directly off a calibrated thimble and barrel, giving you a true micrometric reading in one instrument. The three-point contact system self-centres in the bore, eliminating the rocking error that plagues two-jaw internal mics and delivering repeatable readings without operator technique being a variable.
- Three-point self-centring contact system — Three tungsten carbide-tipped anvils spread 120° apart locate the instrument on the true centreline of the bore automatically. This removes the need to rock and find the minimum reading as you would with a two-point mic, which means faster measurement cycles and results that don’t vary between operators on the shop floor.
- Direct micrometric readout to 0.001mm graduation — Reading directly off the thimble and barrel means no secondary dial indicator to zero, no transfer error from a separate gauge head, and a direct dimensional value you can record or call out without mental arithmetic. For bore tolerances in the H7/H8 range this resolution is more than adequate.
- Hardened and ground measuring faces — The carbide contact points resist wear during repeated insertion into bored bores, ground bores, and reamed holes. On a production run of cylinder liners, hydraulic bodies, or bearing housings, this matters far more than it does on a single-off job — the accuracy doesn’t drift mid-run.
- Newer-style 368 Series body — The 368 Series uses Mitutoyo’s updated barrel and thimble design with a friction thimble (ratchet stop) for consistent measuring force, keeping readings repeatable regardless of how hard the operator winds in. Setting ring required for zeroing; available separately (see seller note below).
- Ideal for — Checking finished bore diameter on turned components on the lathe or machining centre, verifying reamed holes against H7 tolerance, measuring cylinder bores, bearing housing fits, hydraulic valve bodies, and any bored feature in the 62–75mm range where a plug gauge gives pass/fail but you need the actual number.
Condition
(Used — Like New / Well Cared For, Minimal Use)
This Holtest presents in exceptional used condition — about as close to new old stock as a used precision instrument gets. The barrel markings and thimble graduations are crisp and fully legible with no rubbing or wear to the engraving. The carbide measuring faces show no visible pitting, chipping, or flat-spotting under inspection, and the thimble turns smoothly with consistent friction-stop engagement throughout the range — no sticking, grinding, or backlash beyond normal micrometric play. The instrument body carries only the lightest bench patina consistent with careful storage and occasional use; there are no dings, dents, or impact marks to the spindle or measuring head that could indicate a drop or misuse. Functionally, the three contact points extend and retract evenly. As with any used precision instrument, zeroing against a certified setting ring before use is standard practice — a matching setting ring is available separately from the seller, which is the correct way to establish the zero reference on a Holtest regardless of whether it’s new or used. The included calibration certificate provides an additional confidence reference point.
Included:
- 1 x Mitutoyo Holtest 368-141 Three-Point Internal Micrometer, 62–75mm
- Original Mitutoyo wooden storage case
- Original operation manual / papers
- Calibration certificate
- Original accessories (as supplied by Mitutoyo)
Not included: Setting ring (required for zeroing — available separately from the seller; contact Makers Market to enquire about purchasing alongside this instrument).
Brand Information
Mitutoyo Corporation is a Japanese precision instrument manufacturer founded in 1934 and widely regarded as the global benchmark for hand-held metrology tooling. Their products are manufactured in Japan to exacting standards and sit at the top of the market alongside Mahr, Tesa, and Starrett — the instruments you find in NATA-accredited calibration labs and aerospace toolrooms as much as on the average CNC shop floor. When machinists specify “get a Mitutoyo” they’re not paying a brand premium for the name — they’re paying for consistent factory accuracy, long-term parts and calibration support, and instruments that hold their spec over a working lifetime.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model | 368-141 |
| Series | 368 — Holtest Three-Point Internal Micrometer |
| Type | Three-point internal micrometer (self-centring) |
| Measuring Range | 62–75mm |
| Graduation / Resolution | 0.001mm |
| Accuracy | ±0.003mm (refer to calibration certificate for verified value) |
| Measuring Force | Consistent via friction thimble / ratchet stop |
| Contact Points | Three-point, tungsten carbide tipped, 120° spacing |
| Construction | Hardened and ground steel body, carbide measuring faces |
| Country of Origin | Japan |
| Condition | Used — Like New / Well Cared For |
| Included Items | Instrument, original wooden case, operation manual, calibration certificate, original accessories |
| Not Included | Setting ring (available separately from seller) |
Keywords
Mitutoyo 368-141, Mitutoyo Holtest, Mitutoyo three-point internal micrometer, bore mic 62-75mm, internal micrometer 62mm, Holtest 368 series, three point bore gauge, internal mic toolroom, precision bore measurement, bore micrometer Australia, Mitutoyo internal gauge, machining bore inspection
