Extension Rod
Produce Hexagonal and round cross sections, Hexagon 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 a duplicate thread on each end of the steel.,

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 provides 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 harden the entire rod surface both internally and externally to strengthen and extend the life of the rod.
- High Frequency Induction is a process where only the thread ends of the rod are hardened to lengthen thread life.

Extension rod size
R32-Round32-R32 length 3 4 6 8 10 12 ft
T38 (R38) Round39-T38 (38), length 4' 6' 10' 12'ft
T45 -Round46-T45, length 10' 12' 14' 20' ft
T51 -Round52-T51, length 12' 14' 20' ft

MF rod /speed rod size
MF-rod R32-Round32-R32, length 3 4 5 6 10 12 14 ft
MF Rod T38-Round39-T38, length 4 5 6 10 12 14 ft
MF Rod T45-Round46-T45, length 5 6 10 12 14 20 ft
MF Rod T51-Round52-T51, length 6 12 14 20 ft
MF Rod ST58-Round60-ST58, length 12 14 20 ft

(1)Steel grade: 20CrNi3Mo equivalent to SANDBAR 64
SIZE: Hex. 22mm. Hex. 25mm, hex. 28mm. Hex. 32mm hex. 35mm
Dia. 32mm. Dia. 38mm, dia. 45mm dia. 51 mm
(2) Thread: R22, R25, R28, R32, R38, T38, T45, T51, ST58, T60
(3)Length: 0.4m-10m