T38-R39-T38 MM Extension Drill Rod

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 used since the coupling does not enter the hole, this enhances flushing and hole accuracy.

The advantages of drilling with M/M extension drill steel include: easy handling, quicker uncoupling, tighter connections and the potential to drill straighter holes.