Grizzly H5679 Boring Head Set R-8 Anyone creating models or any fine precision work in smaller scales will be glad to see this new Boring Head Set Boring bar sizes (overall length X bore depth X min bore): 2" X 3/4" X 17/64", 2 7/16" X 1 1/8" X 5/16" and 2 13/16" X 1 1/2" X 11/32" Come with 3 boring bars, wrenches and fitted case