Rock Drilling Rod Extention Drill  Rod  And MF Drill Rod 

1).Made from steel as same grade as internationally well-known brand

2).Hollow drill steel processing by Boring Method ensuring quality reliability

3).Optimize processing procedure, entirely automatic threading equipment to finish the thread naturally and reduce the concentration of stress.

4).Shape once of whole heat-treatment ensures long lifespans.
Drill Rod Show :

Extension rods are made by hollow drill steels; there are two shapes of extension rods, round type and hexagonal type. This hollow hole are usually named flushing hole, used for transmitting water or air during drilling. And the threads can be used for connecting couplings, shanks, couplings or bits. 
Usually for extension rods, there are R22, R25, R28, R32, R38, T38, T45, T51, ST58, T60 threads, and different lengths of rods are available from 600mm to 6400mm usually
(1)Steel grade: Male-Male Rod, MF Rod
(2) Thread: R22, R25, R28, R32, R38, T38, T45, T51, 
(3) Rod size: hex. 22mm, hex. 25mm, hex. 28mm, hex. 32mm, hex. 35mm, dia. 39mm, dia. 46mm. dia. 52mm
(3)Length: 0.4m-6m
(4)Package: in wooden case or in bundles. 
(5)Productivity: 20000MT / month