T38 thread:
Extension rods, T38-Round39-T38, length 1220mm/1525mm/1830mm/2435mm/3050mm/3660mm/3965mm/4270mm/4880mm/5530mm/6095mm
Double thread extension rods, T38-Round39-T38, length 3050mm/3660mm
M/F rods, T38-Round39-T38, length 915mm/1220mm/1525mm/1830mm/3050mm/3660mm/4270mm/4880mm/5530mm/6095mm
Guide speed rods, T38-Round46-T38, length 1830mm/3050mm/3660mm/4270mm/4880mm/5530mm/6095mm
Guide tube, T38-Round56-T38, length 1220mm/1525mm/1830mm/3050mm/3660mm/4920mm
Hex extension rods, T38-Hex32-T38, length 1220mm/1830mm/2435mm/3050mm/3660mm
Extension rod:
Other names are Extension drill steel, Extension drill rod, and Extension steel, M/F rod(Speed rod), produce Hexagonal and round cross-sections, Hexagonal rods are more rigid, heavier and transfer energy more efficiently, while increasing flushing. Round rods are generally lighter than hexagonal rods and are normally used in extension drilling applications. With the longer steel tending to be larger in diameter, conventional extension steel is characterized by duplicate thread on each end of the steel.
Extension rods are made by hollow drill steels, different lengths are available from 600mm to 6400mm. This hollow hole are usually named flushing hole, used for transimitting water or air during drilling. And the threads can be used for connecting couplings, shanks adapters or bits.
Male/Female(M/F) rod, speed rod:
M/F drill steel is an alternative to couplings sleeves to include the female part of the threaded connection as an integral part of the drill steel. M/F drill steel procides more rigid connections and is easier to uncouple and handle. The service life also tends to be better than with separate couplings. The advantages of drilling with M/F steel include: easy handling, quicker uncoupling, tighter connections, the potential to drill straighter holes, and longer service life.
For extension rod and M/F steel process, the below two different types of heat treatment are used to strengthen high speed and powerful percussive drill string components to maximize their performance and reliability. Longer steel larger in diameter, conventional extension steel, Hexagonal and round cross sections are available.
Carburization is a process used to harder the entire rod surface both internally and externally to strengthen and extend the life of the rod.
High frequency induction is process where only the thread ends of the rod are hardened to lengthen thread life.
