... parts can be connected by threads. So we say shank adapters, couplings, extension rods, threaded cross bits and threaded button ... the world, there are different drill machines, so different shank adapters are available, like Atlas Copco, Tamrock, Ingersoll Rand,etc. ... same drill machine, due to different applications, the shank adapters can be different length and different threads. Sinodrills shank ...