There are quite a number of factors that you should look out for when selecting rods for a diamond drill. Apart from the material used and the product properties, you should also look at the straightness of the rods. Though it may seem like a lesser quality to consider, rod straightness plays a huge role in terms of rod durability and overall drill success. Here's why.
Reduces wear from the rig
Once the rods are loaded into the rig, they have to be lowered into the drill string through hydraulic movements. The same applies when the rods have to be brought up. The up and down movement of the rods on the rig can cause wear if the rods do not have an even smooth surface. This is because exposed parts will hit the rig loader and create dents or other damage on the rods.
Reduces damage below ground
Once lowered into the ground, the rods come under even more pressure. If the rods are flush, they will bear very little wear as the drill bit will clear the path for them. However, if they are not aligned in a flush setup, they will rub excessively against the ground surface which mostly includes rocks. This, again, will accelerate the wear of the rods.
Avoids dislocation during a drill
As the drill progresses, the whole operation hinges on the reliability of the rod string to stick together. However, if the rods are not straight, the string will not be flush all through. Some rods will be positioned at odd angles. This can force the joints to come apart amid a drill. This is because if the rods aren't flush, then they aren't well locked into place. Such a dislocation can halt the drill and cause undue delays.
Avoids damage to joints due to traction force
If a dislocation does not happen, the rod joints will still be affected. The ill-positioned rods will cause increased wear on the joint ends due to friction and traction force (pressure between rig and drill bit). This will drastically reduce the lifespan of the rods. In the end, the rods will need to be replaced sooner that they ought to be. This can inconvenience your drill operation. In addition to that, it will cost you more than you should.
Enables easy core retrieval
Lastly, if the rod string is not accurately straight from top to bottom, it may affect the ability to bring up core samples later on in the drill. This is because the joints will hinder smooth movement of the sample. Though a total blockage scenario is not easy to come by, challenges of varying degrees may be expected depending on the deviation of the rods.
Remember that the straightness of the rods has to be as accurate as possible. That's because with every rod added to the string, any deviation in straightness will be multiplied. With tens of pipes being used, the end result may be quite skewed. A wireline drill rod supplier or expert will be able to help if you have further questions.