Gives 3 different types diamond knurling pitches by just revolving the head & locking it at any one required position with a screw lock. Shank Size: 6- 1/2" x 1/2" x 7/8" Shank. Fitted with 3 sets of 5/8" x 3/16" x 1/4" Spiral (Right & Left) Coarse, Medium, & fine Knurl Wheels.