(3) common designs of drifter rods

Drifter rods are divided into standard rods and MF rods according to connections with shank adapters. The standard drifter rods are connected to shank adapters through couplings, which is widely used.The MF rodsare designed with couplings integrally to connect with shank adapters. According to different designs of threads connecting with threaded bits, the drifter rods are  divided into drill rods with undercuts and drill rods with slow cutting return. According to different threads, most of drifter rods are connected with shank adapters by T38 threads, and some by R38 threads. Most of drifter rods are connected withdrill bits by R32 threads, and some by TR35 and SR32 threads.