Slotted nut with a long shank and various thrust bearings

Brief description

With this slot cutter, you can cut clean slots for flat dowels on your router—without needing a dedicated Lamello router. It features two carbide cutting edges, a 4 mm cutting width, and a 40 mm outer diameter; it rotates clockwise and is mounted on an 8 mm shank.

The key feature is the guide ball bearing: it guides the cutter along the edge of the workpiece, and its diameter determines how deep the slot will be. Three ball bearings are included—Ø 15, 19, and 23 mm. You loosen the nut at the top, swap out the bearing, and thus set the groove depth for flat dowels in sizes 0, 10, and 20. One tool for all three common Lamello sizes.

This router bit is suitable for softwood, hardwood, and laminated panels. With its 8-mm shank, it fits into any 8-mm collet—on RUWI router tables, hand-held and bench routers, as well as CNC machines. In our own workshop, we use it to cut precise flat dowel joints. You can find more router bits in the router tool section.

Possible applications

• Cut flat dowel slots (Lamello, form springs) for sturdy cabinet and panel joints
• Adjust the groove depth to sizes 0, 10, and 20 using three self-aligning ball bearings (Ø 15, 19, 23 mm)
• Move the ball bearing along the edge of the workpiece without side guidance
• For softwood, hardwood, and laminated panels
• 8-mm shank for RUWI milling tables, hand-held and bench-top routers, and CNC machines

Downloads

RUWI Product Catalog 2026 (PDF)

All the details

• Cutting
- Double-edged (Z2) for clean flat dowel slots
- Cutting width: 4 mm
- Clockwise rotation

• Dimensions and design
- Outer diameter: Ø 40 mm
- Shank Ø 8 mm, shank length 49 mm
- Working length: 4 mm, total length: 70 mm
- Weight: approx. 81 g

• Thrust ball bearings
- Three ball bearings: Ø 15 mm, Ø 19 mm, Ø 23 mm
- For the groove depths of flat dowel sizes 0, 10, and 20

• Material
- Carbide (HW)

• Compatibility
- For softwood, hardwood, and coated panels
- Compatible with RUWI router tables, hand-held and bench routers, as well as CNC machines