Ladder drill in two, one ladder drill, one step ladder twist drill. The difference is that the staircase drilling process size and precision roughness higher, the staircase twist drill can be processed with relatively low precision and roughness of the hole, can also be used as rough with roughing the use of drilling. Both tools are dedicated to the hole processing tool. Ladder twist drill and the use of ordinary twist drill no difference between ordinary twist drill can process materials, ladder twist drill the same can be processed.