Box Joint Router Bits for Excellent Finger Joints This router bit allows you to carry out accurate and functional finger joints in a much easier way. Because the fingers aren't tapered and finish flush and square with the slot and finger the same size, you can work with timbers of different thicknesses without any adjustment. Just run the two work pieces face down on the same reference face and get a flush joint every time. You can also run work pieces through on their ends and cut decorative box joints for fast assembly. Because the cutter heigh is 40mm, you can set the height of the bit exactly half the height of a work piece up to 80mm and run through on both sides to do the full height. The bearing provides a 9.5mm (3/8in) depth of cut. For deeper cuts a fence will need to be used. 1/2in shank box joint bit 12-40mm thickness Shank Size – 1/2in Cutting Height – 12-40mm Cutter Diameter – 47.6 Overall Length – 97.3mm