... for medium and heavy drilling. Super precision key type drill chuck10mm 3/8"-24UNF13mm 1/2 ... drilling machine ,bench and wood working machine.3.The nut and jaws adopt special steel ,durability and ... . High-precision thread and tapered bore closely connected to the tool. 2. Shell, keyhole, keys after quenching. ... . 4. Gears and gear housing Pressing the key. 5. Accuracy accurate and reliable, durable ...