It is common practice to bump up the drive end of drifting drill steel for added strength at the rock drill end to accommodate larger diameter and shank adapters. Drill steel of rock drilling tools is available in many standard lengths to match the drill feeds on a multitude of available drifting jumbos. A rock drill bit diameter closer to the steel diameter can be usedsince the coupling does not enter the hole, this enhances flushing and hole accuracy.
T38 MM ROD 3050MM
The advantages of drilling with M/M extension drill steel include: easy handling, quicker uncoupling, tighter connections and the