Drill pipe is the most expensive wear part on any horizontal directional drill and there are many important factors to take into consideration when in the market for new pipe. We are going to examine how to know when it’s the right time to purchase new drill pipe.
First examine the rod to make sure it has not been bent. If the rod is not straight set aside for further evaluation. Next, visually inspect the pin and box connections because the connection between the two rods is by far the area that is most susceptible to failure. Inspect the threads for galling and wear. This is something that should be done on a continual basis, not just when your pipe is getting near the end of its life. A thread profile gauge is a very useful and inexpensive tool to use when evaluating thread wear also. You will also want to measure the outside diameter of the box end tool joint tong spaces with a caliper for wear because the ability of the pipe to carry its designed torque load is directly proportional to the surface area of the connection. It’s time to start watching your pipe closely when that surface area has been diminished by roughly 0.075”. As wear progresses past this point the torque rating of the pipe will become compromised, so if and when it drops below the torque output of the drill you will be risking failure with every make up, as well as every other function the pipe is designed to perform. Flared box ends and mushrooming pin ends of tool joints are another indicator of significant wear, not to mention potential make up process issues. If you are experiencing some, or several of the issues mentioned above you are likely approaching the time to purchase new pipe.