Authentic negative rake replacement cutter fits Simple Woodturning Tools engraved with SR. Negative Rake Cutters are perfect for turning man made materials like resins or acrylics. Simple Woodturning Tools are machined for this exact cutter. Other cutters may not work. Negative Rake Carbide Cutter for SR tool. Ideal for turning resins or acrylics. This negative rake replacement carbide cutter was designed to fit the Full Size Simple Rougher (tools engraved with SR). This cutter is for the full size tool only, it will not fit the mid size tool engraved with MSR or the Simple Start tool engraved with SSR. Specifications: 15mm x 15mm. Screw required for this cutter is M6 X 1 x 8mm length.