Q.Max QMA20M Sheet Metal Punch 20mm A quick and easy way to cut clean metric sized holes in sheet metal up to 16 gauge. The special design allows even load during cutting and produces a burr free hole that needs no extra finishing. Heat treated cutting edges with black anti-corrosive surface finish to prevent rusting. All punches are sold singly without key which should be ordered separately. Thread the punch onto the hexagonal screw and then pass the hexagonal screw through the hole. Position the die on top of the die nut and then screw the die nut onto the projecting hexagonal screw until it touches the metal sheet. Use a hexagonal key to turn the hexagonal screw. The screw will pull the punch through the metal and a hole will result. Please note these instructions apply to cutters up to 15 mm in size for cutters 15 mm and over have a different configuration. Notably they have fewer components in the larger cutters the thread is in the punch and thus there is no die nut.