HSS-Co8. The break-proof design of the keyhole saws makes them perfect for cutting round holes in practically all machinable materials, including cast iron, stainless steel, tool steel, copper, bronze, aluminium and wood. All dimensions have a 4/6 combi-tooth and can be used for cutting depths of up to 38 mm.. The associated mounting shanks enable quick and easy clamping in hand-held and stationary drills Supplied without adapter shank