Description
Product Overview
The Nikko 100mm Sine Bar is a precision ground reference tool used to set and verify exact angles in the toolroom and on the surface grinder. With a hardened and ground steel body, precision ground cylinder rolls, and a nominal 100mm centre distance between rolls, this sine bar lets you dial in angles to within seconds of arc when used correctly with gauge blocks — a level of angular accuracy that a protractor simply cannot touch.
- 100mm roll centre distance — The 100mm dimension is the working constant of the bar. Sine calculations are clean and fast: sine of the required angle multiplied by 100 gives you the stack height in millimetres directly, with no conversion factor needed. This makes gauge block selection straightforward at the bench.
- Hardened and precision ground working surface — The top face and side references are ground flat and parallel to tight tolerances, giving you a reliable datum when setting up angular work on a magnetic chuck or surface plate. Any deviation in that ground face corrupts your angle setup — on a quality sine bar, it won’t.
- Precision ground cylinder rolls — The rolls are the critical components. They need to be equal in diameter and truly cylindrical for the trigonometric relationship to hold. Worn or out-of-round rolls introduce angular error that compounds across the sine function — particularly noticeable at steeper angles above 45°.
- Compatibility / accessories — This sine bar is used in conjunction with a set of slip gauges (gauge blocks) and a surface plate or magnetic chuck. Neither gauge blocks nor a surface plate are included. The bar also features relief holes through the body, reducing weight and providing clamping points for workholding on the grinder.
- Ideal for — Setting precise angles on a surface grinder for form tool grinding, angular relief grinding on HSS tool bits, setting up sine vices, verifying taper angles on ground components, and checking angular accuracy of machined features against a reference surface plate.
Condition
Used (Good Condition / Pre-owned, Fully Functional)
The working surfaces of this sine bar — the top face and the cylinder rolls — present well, with no visible damage, burrs, or deformation to the critical ground areas. The rolls appear intact and undamaged, which is the most important thing to confirm on a used sine bar; a dinged or pitted roll face is a deal-breaker for accuracy, and these look sound. The body carries a light patina and handling marks consistent with careful toolroom use, but nothing that affects the reference surfaces. The original wooden storage box is included and is in used but functional condition, showing wear appropriate to its age — it does its job of protecting the bar in storage and transit. A date code written in red on the lid reads “48-10-12,” which likely indicates a manufacture or inspection date. As with any pre-owned precision tool, we recommend verifying the roll diameters for equality with a bench micrometer and checking the top face for flatness on a known surface plate before committing it to critical work. For most toolroom and surface grinding applications this bar will perform exactly as intended.Included:
- 1 x Nikko 100mm Sine Bar (No. 7347)
- 1 x Original wooden storage box
Not included:
- Gauge blocks / slip gauges (required for use)
- Surface plate (required for use)
- Calibration certificate
Brand Information
Nikko is a Japanese manufacturer of precision metrology and machine tool accessories, producing hardened and ground toolroom equipment to standards consistent with Japan’s reputation for rigorous dimensional accuracy in the metrology sector. Japanese-made sine bars and angle references from this era sit in the same reliable mid-to-upper tier as brands such as RSK and Showa, offering genuine toolroom-grade accuracy at a practical price point compared to European equivalents. Nikko tooling was widely imported into the Asia-Pacific region and has a solid track record in production and toolroom environments across Australia.
Specifications
| Feature | Specification |
|---|---|
| Brand | Nikko |
| Model / Catalogue No. | No. 7347 |
| Type | Sine Bar |
| Roll Centre Distance | 100mm |
| Body Material | Hardened and precision ground steel |
| Rolls | Precision ground cylinder rolls (2x), equal diameter |
| Body Features | Relief holes through body for weight reduction and clamping access |
| Accuracy | To Japanese toolroom grade (verify against master blocks if critical) |
| Country of Origin | Japan |
| Condition | Used (Good Condition) |
| Included Items | Sine bar, original wooden storage box |
| Not Included | Gauge blocks, surface plate, calibration certificate |
Keywords
Nikko sine bar, Nikko 100mm sine bar, sine bar No 7347, precision sine bar Australia, 100mm sine bar toolroom, Japanese sine bar, surface grinder angle setup, angle setting tool machinist, toolroom sine bar, slip gauge sine bar setup, precision angle reference, sine bar surface plate
