The drill rod string is the transmitter of the rotation and torque to the cutting tool. Must be hollow to allow circulation of the drilling fluid to the front of the core barrel (core bit).
There are different types of drill rods and different diameters. The type of fitting with another rod varies in different standards.
The characteristics of the steels which TECSO, S.A. manufactures its drill rods, are higher than those required by the standard governing them.
A balanced and in good condition drill rod string causes the rotational motion and torque is transmitted vibration free and without swinging.
This prevents premature wear and breakage of the materials.
It is especially important when working with diamond bits.