Dimar 108R4-X-X Series Adjustable Slotting CNC Router Bit SystemAdjustable Slotting Router Bits offer the flexibility of adjusting the kerf to the desired width, from 1 8 to 1 4 or 1 4 to 1 2 without the use of shims. By releasing the counter nut, one can set the kerf using a precise dial. By rotating the dial, you are able to change the kerf in 0. 01 increments. This system saves a lot of time needed to adjust and readjust a conventional slotting router bit to the right kerf