Router cutter HS single-edged, with base blade

Single-flute end-cutting groove cutters in HS steel, 3 to 5 mm, 8 mm shank. HS steel takes a keener edge than carbide and runs smoothly in softwood, which is exactly where these belong. In board or hardwood they blunt quickly — reach for the carbide equivalents there. Inexpensive enough to treat as consumable.