Grizzly H5939 R-8 Boring Head Set, 18-Piece 2 facing tools with 3/16-Inch square HSS cutting tools; Stand included 2-Inch boring head with 7/8-Inch-20 mounting threads 9 carbide tipped boring bars with 1/2-Inch shanks Dial graduated in .001-Inch. .050-Inch per revolution / .025-Inch actual motion R-8 shank with 7/16-Inch-20 mounting threads for drawbar