Extension rods are one major spare part in terms of drill application area, there are two shapes of extension rods, one is round type, another one is hexagonal type.
But all extension rods are threaded and made by hollow drill steels, this means usually extension rods are hollow.This hollow hole are usually named flushing hole, used for transmitting water or air during drilling. Two ends threads can be used for connecting couplings, shanks, couplings or bits. Typically two ends of extension rods are male, while sometime one end is male and another one is female, then we call it M/F rod. We need couplings to connect extension rods, while for M/F rods, because one end is female, so couplings are not necessary.
Drill rod using thread system. Drilling precision can be further improved by using this as the first rod in a normal drill string. Furthermore, since this is a speed rod design it will produce straighter holes and at least 10% higher penetration rate in good rock conditions compared to rod and coupling sleeve combination system.
Widely used in drifting, tunneling, benching, and long hole drilling
High strength chromium-molybdenum steel with high fatigue strength and excellent wear resistance
For extension drill rod, there are R22, R25, R28, R32, R38, T38, T45, T51, ST58, GT60 threads, and different lengths of rods are available from 600mm to 6400mm.
Xiamen Bestlink Factory Co., Ltd is committed to provide the best drilling and cutting machine, tools and accessories products in marble and granite stone quarrying, as well as in civil engineering application, especial demolition project. it is now a leading manufacturer of cutting and drilling equipment for the extraction of marble, granite and ornamental stones in china.