It’s important to have a maintenance program for your down-the-hole tools.
By LaTisha Shipman
I’m not sure where this year went. It seemed to fly by! How are we already in the midst of dealing with winter weather?
Preparing our down-the-hole (DTH) tooling for winter differs significantly from coast to coast and from North to South. Here in Texas, we drill pretty much all year. We might take off a week or two in February while everything seems to freeze over, but that’s really the extent of our winter most years.
But I think no matter where you’re located, we all have some expected downtime during the winter months.
Winter To-Do List
An inclement weather day is an excellent opportunity to carry out that much-needed maintenance on our tooling and equipment. I’m sure you already have a list a mile long of things to repair or upgrade this winter. Please consider implementing a maintenance program for your DTH tooling while you’re making your winter to-do list.
Now would be a great time to tear down and inspect your hammer. If you’re going to be down for an extended period of time, I recommend completely tearing the hammer down and inspecting the wear limits of each part. You can get the dimensions from your hammer manufacturer or distributor.
Check for worn areas and replace parts as necessary, paying special attention to the splines of your chuck, the striking end of your piston, and replace all soft-packing such as O-rings.
Inspect the check valve and spring and replace if necessary. Inspect the piston for cracking or wear. If you have a reversible wear sleeve on your hammer, now is a good time to reverse and reassemble. Liberally reapply thread compound to your tool joints, and oil your hammer parts before reassembling.
Proper Storage Procedures
If you’re going to be storing your hammer this winter, please refer to the proper storage procedures listed here:
Short Term (three weeks or less): Blow air and oil through the hammer to ensure all parts are clean and lubricated. Any debris left in the hammer can cause the piston to seize. Store horizontally in a dry, temperature-controlled location with both ends covered with protective caps.
Long Term (longer than three weeks): Tear the hammer down completely and wipe down all parts and coat with oil. Store the assembled or disassembled hammer in a dry, temperature- controlled location. If the hammer is assembled, store it with both ends covered with protective caps.
Other Action Items
Another action item to add during the winter months is to make sure your hammer oiler/lubricator is working properly. Test it to make sure the output is what you expect it to be.
We have seen some hammer failures due to lack of lubrication where the cause of failure was simply the lubricator; it had stopped working unbeknownst to the driller. The piston seized up in the hammer and had to be replaced completely. This is a good example of why downtime is a good time to make sure all parts on your rig are functioning properly.
Cold weather days are also a good time to resharpen carbide on your used bits, keeping them as a good backup that will save you time and money in case of a bit failure later. It is worth noting that not all carbide is able to be re-sharpened—coated carbide falls into this category.
Check to make sure your blow tubes are seated properly and are tight, and change them out if necessary. Inspect the drill bit splines and remove any sharp edges with a file. If the splines of the bit are in rough condition, please also inspect the splines on the chuck, and if worn, replace the chuck.
If you are continuing to drill through the cold winter months, you might consider changing the rock drill oil that you use. At temperatures below freezing, using a rock drill oil with an antifreeze additive may be required. For ambient temperatures below 50°F, 100 weight rock drill oil is recommended.
I would also like to remind you that your drilling foam can separate and freeze, so please keep your foam stored inside during these upcoming cold months. If it separates, it’s pretty much ruined.
Keep in mind when drilling in cold winter months the CFM on your compressor must be adjusted to overcome the effects of extreme temperatures. Cold air is denser and exerts more pressure. Please see your hammer or compressor manufacturer to reference correction factor charts for temperature and altitude.
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For many parts of the country the winter months are a time to catch our breath. They are also an ideal time to do much-needed maintenance on our equipment and tooling. Please make sure you do. Time flies, and before you know it, the weather will thaw, and that job list will be long once again.
LaTisha Shipman is the Texas branch manager for Drilling Equipment Resources. She has more than 20 years of experience in the drilling industry, with most of that time spent working in manufacturing with DTH hammers and bits. She can be reached at latisha@drillingequipmentresources.com.