Description
Peacock CG-3 Dial Bore Gauge Kit — 50–100mm
The Peacock CG-3 is a competent, workshop-proven dial bore gauge kit covering the 50–100mm range — the bread-and-butter capacity for engine rebuilders, toolmakers, and machining shops checking bored holes, cylinder bores, and precision fits. Paired with Peacock’s own No.36B dial indicator, this kit gives you a complete, ready-to-use internal measurement setup straight out of the case, without sourcing extra accessories. Whether you’re checking a freshly bored cylinder for taper and out-of-round, verifying a reamed housing bore against a H7 tolerance, or setting up a boring head for a precision fit, this gauge gives you the reach and resolution to do it properly.
- 50–100mm measuring range with graduated extension anvils — The kit ships with a full set of interchangeable measuring anvils (0.5, 1, 2, 3mm steps visible in the tray, scaling up to cover the full 50–100mm capacity). This matters because a bore gauge without its full anvil set forces you to compromise — gaps in coverage mean you’re either reaching for a different gauge or improvising. With the complete set, you can step through the range continuously without interruption.
- Peacock No.36B dial indicator, 0.01mm graduation — The analogue dial indicator reads in 0.01mm increments, which is sufficient resolution for most production and toolroom bore checking. On a 0.01mm-per-division gauge, one graduation is roughly 0.4 thou — more than adequate for clearance fits, bearing housing checks, and cylinder ovality measurement where you’re working to tolerances in the order of 0.02–0.05mm.
- Rigid one-piece gauge body — CG-3 series — The CG-3 body uses a centralising mechanism that self-centres the measuring head in the bore, ensuring the gauge always reads on the true diameter rather than a chord. This is the critical design feature that separates a dial bore gauge from a telescoping gauge — the reading is repeatable and operator-independent once you’ve found the rocking minimum, which is the correct measurement technique.
- Complete kit in fitted case — All anvils, the gauge body, the dial indicator, and ancillary hardware are housed in the original moulded plastic case. A complete kit in its original case is worth noting — individual Peacock replacement anvils and spare parts aren’t always easy to source in Australia, so having every piece accounted for is a genuine practical advantage.
- Ideal for — Cylinder bore measurement (taper, ovality, and wear checks on engine rebuilds), checking precision-bored housings and bearing fits, verifying reamed holes against H6/H7 tolerances, inspecting hydraulic cylinder bores, and production QC of machined bores in the 50–100mm range.
Condition
Used (Good Condition / Complete Kit, Minor Modification)
The gauge body and anvil set are in good working condition. The centralising head moves freely, the measuring anvils are present and undamaged, and the dial indicator (Peacock No.36B) functions as expected with a live, responsive needle. The critical precision surfaces — the measuring anvil contacts and the bore-contacting reference points — show normal workshop patina consistent with a used tool but no visible damage that would compromise measurement integrity. The anvil tray appears complete across the full range from 50mm to 100mm, with both the small-increment spacers (0.5, 1, 2, 3mm) and the larger stepped anvils visible and accounted for.
One modification requires clear disclosure: the rear mounting eyelet on the dial indicator has been cut off. This eyelet is used for lug-back mounting of the indicator to a stand or arm — its removal does not affect the indicator’s function when mounted in the bore gauge body, where it seats and clamps via the indicator stem in the conventional manner. However, if you intended to repurpose this indicator separately as a standalone dial indicator mounted to a magnetic base or indicator stand via the lug, that option is no longer available without a replacement indicator. For use as a dedicated bore gauge indicator — its primary purpose here — this modification is functionally irrelevant.
As with any used bore gauge, we recommend verifying zero against a calibrated ring gauge or a precision-bored master before putting this tool into critical production work. For general workshop use, engine rebuilding, and toolroom checking, it is ready to use as received.
Included:
- 1 x Peacock CG-3 Dial Bore Gauge Body — 50–100mm
- 1 x Peacock No.36B Dial Indicator (0.01mm graduation) — rear mounting eyelet removed
- 1 x Full set of interchangeable measuring anvils (50–100mm range)
- 1 x Original fitted plastic carry case
Not included:
- Setting ring gauge / master ring (required for accurate zeroing — not supplied, buyer to source separately)
Brand Information
Peacock is a Japanese precision instrument brand manufactured by Ozaki Mfg. Co., Ltd., with a production history spanning several decades in the metrology and precision gauging sector. Their dial indicators and bore gauging systems are manufactured in Japan to toolroom-grade standards and sit comfortably alongside RSK and Mitutoyo in the mid-to-upper tier of the Japanese metrology market — a meaningful endorsement given Japan’s well-established reputation for consistent, high-accuracy gauge manufacture. Peacock instruments are used across automotive, aerospace, and general engineering environments where Japanese build quality and long-term reliability are valued over budget-tier alternatives.
Specifications
| Feature | Specification |
|---|---|
| Brand | Peacock (Ozaki Mfg. Co., Ltd.) |
| Model | CG-3 Dial Bore Gauge Kit |
| Dial Indicator Model | Peacock No.36B |
| Type | Dial Bore Gauge (Centralising) |
| Measuring Range / Capacity | 50–100mm |
| Graduation / Resolution | 0.01mm per division |
| Anvil Set | Full set included — 0.5, 1, 2, 3mm increments plus range anvils |
| Indicator Mount | Standard stem mount to gauge body; rear lug eyelet removed on indicator |
| Construction | Steel gauge body, hardened measuring contacts |
| Country of Origin | Japan |
| Condition | Used — Good Condition / Complete Kit, minor modification (lug removed) |
| Included Items | CG-3 gauge body, Peacock No.36B indicator, full anvil set, original fitted case |
| Not Included | Setting / master ring gauge |
Keywords
Peacock CG-3 bore gauge, Peacock dial bore gauge, dial bore gauge 50-100mm, internal bore gauge kit, cylinder bore gauge Australia, bore mic 50-100mm, Peacock No.36B dial indicator, toolroom bore gauge, engine rebuild bore measurement, internal measuring gauge, bore gauge set Japan, precision bore gauge machinist
