Description
Contact wheels are the heart of the Radius Master system. Each diameter produces a distinctly different grinding profile — from the sharp, tight inside radius of the 19mm wheel through to the broad, gentle sweep of the 50mm. Having the right wheel for the job means the difference between a grinding pass that takes seconds and one that requires multiple compromises with the wrong profile.
These small wheels are 50mm wide, matching the 50 x 1220mm (2″ x 48″) belt used by the Radius Master and Blade Master machines. All wheels feature a smooth rubber surface for consistent belt contact and clean, controlled grinding across the full belt width.
What’s included varies by size:
- 19mm, 22mm, 25mm, 32mm, and 38mm wheels — supplied complete with bearings and mounting screws, ready to install directly onto the machine’s contact wheel spindle.
- 44mm wheel — contact NIROC to confirm inclusions.
- 50mm wheel — supplied with the shaft included, as this size mounts differently to the smaller wheels.
Each size opens up specific grinding capabilities:
- 19mm — extreme tight radius work; finger choils, deep narrow grooves, fine detail on jewellery and instrument work. Variable speed grinders only at medium-low speed; monitor bearing temperatures.
- 22mm — tight radius choils and inside curves with slightly more belt surface contact than the 19mm.
- 25mm — the smallest wheel in the standard RM-48 kit; a versatile tight-radius option for knife choils, fuller entry points, and precision notch work.
- 32mm — mid-small radius; useful for moderate inside curves, guard fit-up, and handle shaping.
- 38mm — approaching mid-range; good for fuller grinding, sweep blending, and larger choil work.
- 44mm — larger small wheel; smooth sweep grinding on blades and curved stock.
- 50mm — a full 2″ diameter contact wheel; popular in the Three-Wheel Cluster assembly and as a standalone grinding station for medium-radius hollow grinds and profiling.
These wheels are fully compatible with the Three-Wheel Cluster Upgrade Kit — if you own a cluster, individual small wheels are available as replacements when a wheel in your cluster is worn.
Company Information
Genuine Radius Master contact wheels are manufactured by NIROC, the Australian company that acquired Radius Master Machinery in 2025 and continues to build and supply the full Radius Master range. NIROC’s lead maker, Corin Urquhart, is a practising knifemaker with over 20 years of daily belt grinder use — the parts and accessories NIROC supplies are designed and validated by people who depend on them in real workshop conditions. All wheels are manufactured to match the original specification for fit, rubber durometer, and bearing quality.
Features & Specifications
| Feature | Specification |
|---|---|
| Make | Radius Master / NIROC |
| Product Name | Small Contact Wheels — 50mm Wide |
| Part Type | Genuine OEM contact wheel |
| Width | 50mm (suits 50 x 1220mm belt) |
| Available Diameters | 19mm, 22mm, 25mm, 32mm, 38mm, 44mm, 50mm |
| Surface | Smooth rubber |
| Compatible Machines | Radius Master RM-48, RM48AE-VS (Series 2); Blade Master belt grinders |
| Also compatible with | Three-Wheel Cluster Upgrade Kit (as replacement wheels) |
| 19–38mm inclusions | Complete with bearings and mounting screws |
| 50mm inclusions | Supplied with shaft |
| Country of Origin | Australia |
Further Information
Choosing the Right Size
If you are replacing a worn wheel, match the diameter of your existing wheel. If you are adding a new size to your setup, consider where the gaps are in your current contact wheel range. The standard RM-48 kit includes 25mm, 38mm, 44mm, 50mm, and 88mm wheels — meaning 19mm and 22mm are the sizes most commonly added by knifemakers seeking tighter radius capability for choil and detail work.
Variable Speed Note for Very Small Wheels
The 19mm and 22mm wheels spin at significantly higher RPM than larger wheels for any given belt speed, which increases bearing load and heat generation. These very small wheels are best used with a variable speed machine (RM48AE-VS) at medium to low belt speeds. Monitor bearing temperatures when first using these wheels in your workflow, particularly during extended grinding sessions.
Compatibility with Three-Wheel Cluster
If you own the Radius Master Three-Wheel Cluster Upgrade Kit, individual wheels from this range can be used as cluster replacement wheels when one of the cluster wheels becomes worn or damaged — extending the service life of your cluster assembly.
