Description
Product Overview
The Mitutoyo 526-150 Dial Hole Gauge is a precision small-bore measuring instrument designed to accurately measure internal diameters from 3.7 mm to 7.3 mm — a range that covers the fiddly, hard-to-reach bores where standard inside micrometers simply won’t fit. Supplied as a full kit with interchangeable contact points, this is a toolroom-grade instrument built to Mitutoyo’s exacting Japanese manufacturing standards, ready to go straight onto the bench.
- Interchangeable contact system across seven size steps (4.0–7.0 mm nominal heads): The kit includes multiple anvil heads covering the full 3.7–7.3 mm range in incremental steps (3.7–4.3, 4.2–4.8, 4.7–5.3, 5.0–5.8, 5.7–6.3, 6.2–6.8, 6.7–7.3 mm). This matters because each head is optimised for its sub-range — you’re not stretching one contact point across the full span and compromising repeatability at the extremes.
- Dial indicator mount for your own indicator: The 526-150 body accepts a dial indicator via its dedicated mount — meaning you use your own tenths or thou-reading indicator, so you’re reading from a gauge face you already trust and know how to zero. This also lets you upgrade indicator resolution without replacing the whole instrument.
- Hardened and ground measuring faces: The contact tips are ground to a high surface finish, which keeps measurement scatter low when checking small bores like pin holes, hydraulic ports, dowel locations, and reamed holes. Hard faces resist wear in production use and hold their geometry far longer than cheaper cast alternatives.
- Compatibility note: This kit is supplied without a dial indicator — you will need to fit your own (standard stem size; verify against Mitutoyo 526-series specifications for stem diameter before fitting). A setting ring is included for zeroing the gauge to a known reference — essential for accurate comparative measurement.
- Ideal for: Checking reamed pin-hole diameters, verifying hydraulic valve body bores, inspecting small bushings and bearing housings, checking four-jaw chuck collet bores, production inspection of drilled and reamed holes in the 4–7 mm range, and any application where a telescope gauge would sacrifice repeatability.
Condition
Used (Good Condition / Like New — Full Kit, No Dial Indicator)
This 526-150 presents exceptionally well for a used instrument — the seller describes it as “like new,” and the photographs support that. The contact heads and anvil tips show no visible wear or burring, and the measuring faces appear clean and free from the pitting or corrosion that can compromise small-bore gauges stored poorly. The body and grip show no significant handling marks. All interchangeable heads are present and individually bagged, consistent with a kit that has seen light use or careful storage. The original orange carry case is intact and structurally sound, with the foam insert holding all components securely in their correct positions — a good sign the kit has been stored correctly rather than rattled around loose in a drawer.
The kit is supplied without a dial indicator — this is normal for the 526-series, which is designed to accept the user’s own indicator, but it is worth confirming you have a compatible indicator before purchase. No cosmetic or mechanical issues have been identified that would affect measurement function. As with any used precision instrument, we recommend verifying zero against the included setting ring and, if the application demands certified traceability, having the instrument calibrated against a NATA-traceable ring gauge before use in a formal inspection role.
Included:
- 1 x Mitutoyo 526-150 Dial Hole Gauge body and grip assembly (3.7–7.3 mm)
- 7 x Interchangeable measuring heads (full size range, individually bagged)
- 1 x Setting ring (for zeroing / reference)
- 1 x Spanner (for head changes)
- 1 x Original Mitutoyo carry case with foam insert
- 1 x Original instruction sheet / manual (Japanese and English)
- 1 x Calibration certificate / inspection papers
Not included:
- Dial indicator (must be sourced separately — not supplied by Mitutoyo with this model)
Brand Information
Mitutoyo Corporation, founded in Japan in 1934, is the world’s largest manufacturer of precision measuring instruments and is widely regarded as the benchmark against which other metrology brands are judged. Their product line spans micrometers, verniers, CMMs, surface plates, and specialised gauging — all manufactured to exacting tolerances in their Japanese facilities. In the Australian toolroom and production environment, Mitutoyo sits at the top tier alongside Mahr and Tesa, and is the default specification on most aerospace, defence, and automotive inspection drawings where brand is called out.
Specifications
| Feature | Specification |
|---|---|
| Brand | Mitutoyo |
| Model | 526-150 |
| Type | Dial Hole Gauge (Small Bore Gauge) |
| Series | 526 |
| Measuring Range (Full Kit) | 3.7–7.3 mm |
| Head Sub-Ranges | 3.7–4.3 / 4.2–4.8 / 4.7–5.3 / 5.0–5.8 / 5.7–6.3 / 6.2–6.8 / 6.7–7.3 mm |
| Number of Heads Included | 7 |
| Dial Indicator | Not included — user-supplied (check stem compatibility with Mitutoyo 526-series) |
| Measuring Face Material | Hardened and ground steel |
| Country of Origin | Japan |
| Condition | Used (Good Condition / Like New) |
| Included Items | Gauge body, 7 x measuring heads, setting ring, spanner, carry case, instruction sheet, calibration certificate |
| Not Included | Dial indicator |
Keywords
Mitutoyo 526-150, Mitutoyo dial hole gauge, Mitutoyo small bore gauge, dial hole gauge 3.7-7.3mm, small bore gauge kit, internal bore gauge Japan, hole gauge toolroom, bore gauge machinist, precision bore measurement, reamed hole inspection, internal diameter gauge Australia, Mitutoyo 526 series
