Union Butterfield 1010405 1588 Spiral Flute Tap, Right Hand Cutting, 5/16-24 Thread, H3 Thread Limit, Bottoming Chamfer, Right Hand Flute Direction, 3 Flutes, Bright, HSS
Similar to the regular spiral flute design of 1582/1586 except that the faster spiral improves the chip drawing action and permits the bridging of larger gaps inside a hole