Woodworkers use lots of different methods to cut tenons for mortise and tenon joinery. I have used a big Forstner bit and my drill press to waste stock, cut them with a dado blade on a table saw, and even used a hand saw. CMT's carbide tipped Tenon cutter will now have me cutting tenons with my router - and I'll get more consistent tenons with less work! Made like one half of a tongue and groove cutter, the bit set has four stackable 2 tooth cutters which are separated using a variety of spacers (included). Consistently sized tenons from 3/16 to 3/8 thick and up to 1-1/16 long are made easily, since variations in board thickness only affect the position of the tenon, not the thickness. Make all tenon cuts face down so any variation occurs on the back. Use this router bit in a table mounted router only with a miter gauge and backup block, and at speeds less than 12,000 RPM. Made in Italy.