Not all hammer warranties are the same, so it’s important you are familiar with yours.
By LaTisha Shipman
It’s important to have realistic expectations with your hammer warranty.
Not all hammer manufacturer’s warranty policies are the same, and you should always read the manual to see how long your hammer will be under warranty and what all it covers.
Most often, hammer warranty only covers manufacturing defects, and only for a certain period of time. Normal wear and tear and improper use are not covered. Knowing that, let’s review things that are common between hammer manufacturers regarding their warranty.
First, I suggest keeping your hammer manual in a file at the office with the serial number written down inside. That way you can easily reference it in the event you need to file a warranty claim. There is a master serial number for the hammer often stamped on the top sub, but there can also be a piston serial number stamped on the piston, and other parts might be stamped as well.
Keep your good used bits as backups, regrinding the buttons for best results.
If you have the opportunity to disassemble the hammer upon receipt and log these numbers, it might be helpful to you later on. Some serial numbers are stamped better than others, but over time, they can fade with normal wear and tear, and it can be difficult to determine any identifiable markings on the hammer. Logging the stamped markings can also help when needing to reorder parts.
Causes Not Covered
Here are some of the common causes of premature hammer wear or failure that are not covered under warranty.
Incorrect lubrication/lack of lubrication
Not oiling the hammer properly can create excessive heat within the hammer, causing the parts to become brittle or even melting parts inside that are not metal—darts, make-up rings, or O-rings.
Lack of lubrication can also cause bits to shank across the splines. You may also need to change the grade of oil you use between summer and winter months, depending on what area of the country you are in.
If you are drilling with water injection, use the next higher grade of rock drill oil than what is recommended and increase the recommended dosage as well. A good rule of thumb is to double the recommended amount of oil suggested when using foam or water.
Water/debris contamination
If you are drilling in acidic conditions, your hammer can fail prematurely due to contamination. Proper lubrication can help combat acidic conditions and protect your hammer. Anytime there is debris in the hammer, parts can fail.
Keep the hammer flushed clean with dry air and oil. This is helpful especially at the end of your day. Even the foam you use can be corrosive to hammer parts.
We often see debris between the striking face of the piston and striking face of the bit. If this is severe, you might want to reduce the amount of water injection. If you see damage on the anvil end of the bit, you also need to check the anvil end of the piston.
You can resurface the striking face if you see evidence of erosion. Otherwise, it can lead to catastrophic failure of the piston or the bit.
Insufficient clearance between hammer and bit
When possible, it is probably best to run the same brand of hammers and bits together. The reason being is that dimensions can differ, even slightly, from one manufacturer to the next and cause you to experience clearance issues.
If the hammer manufacturer is on the lower end of their tolerance and the bit manufacturer is on the higher end of their tolerance, you can have an interference fit. If the fit is too tight, it can lead to galling in the splines of the bit and the chuck.
Okay, I know it can be difficult at times to run the same brand bit as the hammer with lead times the way they are and lack of inventory. But you can help yourself by planning ahead and having a backup bit on hand. Also, ask your distributor if they would be willing to stock a bit for you. Keep your good used bits as backups, regrinding the buttons for best results.
Inadequate removal of cuttings
If you are regrinding cuttings at the bottom of the hole, that will normally wear most on your bit face, but you will also start to see rapid wear on the chuck and the chuck end of your wear sleeve.
If you have a reversible sleeve, you can flip the sleeve to get longer life from your hammer. Be sure to monitor wear prematurely.
Running your hammer past its wear limits can also lead to failure. Make sure your air pressure and foam are sufficient to aid in cuttings evacuation.
Too much weight or not enough weight
Both will have adverse effects on your hammer, leading to premature wear or failure. We see evidence of this by inspecting the splines of both the chuck and the bit. The splines can wear in a tapered pattern, which is indicative that the hammer has been running in the open position, and not fully cycling, leading to increased wear.
If you see tapered splines on your bit, you also need to check the chuck splines as well. If you install a new bit on a worn chuck, the new bit will fail. Insufficient weight on the bit when drilling in unconsolidated materials can loosen the chuck, which can result in lost tooling downhole.
Poor servicing tools
Many wear sleeves are damaged by improperly using servicing tools or not using the correct servicing tools. Do not apply force to the threaded areas on the wear sleeve.
When breaking connections on your hammer, please make sure the chains on your breakout wrench are in the proper place which is often indicated in your hammer manual. Otherwise you can crack the threads or warp the wear sleeve.
Do not weld or apply heat to break out the hammer, especially while it is under warranty—it can negate the warranty on your hammer. I want to reiterate, please do not weld on your hammer while it is under warranty—it will void your warranty.
Thread failures
Many top sub thread failures are the result of not regularly reapplying thread compound. The threads are exposed to corrosion through the use of foam, so it is important to apply adequate amounts of thread protectant.
Wear sleeve threads are often damaged through improper use of breakout wrenches as previously mentioned. It is important to also keep these threads coated with compound.
Another failure you might experience with threads can be attributed to loose tool joints. Always check to make sure your tooling is adequately torqued up. Applying too much torque can also lead to thread failures.
Submitting a Claim
When you submit a warranty claim, it’s important to fill out the necessary paperwork or to at least verbally answer the questions so the hammer manufacturer can properly assess the failure.
You can realistically expect to answer a 20-question quiz about your operational parameters. Some of the questions you will most likely encounter are:
- Hammer make, model, and serial number
- Air compressor PSI and CFM
- Operating pressure at the time of failure
- Weight on bit: thrust/pulldown
- Rate of penetration
- Rotations per minute (RPM)
- What type of rock drill oil and rate of lubrication?
- Are you drilling with water or foam?
- Part life received vs. part life expected: How much footage did you have on the hammer when it broke and how much footage would you expect to get out of the hammer in your drilling conditions? This can vary depending upon formation and other factors.
Wrapping Up
No one can correct a problem they don’t know about, so please communicate with your distributor and manufacturer when you experience a problem.
Be aware that your distributor or manufacturer will have many questions about the events prior to the failure and at the point of failure. The best thing you can do to protect your asset is to use it as the manufacturer suggests, especially while it’s under warranty.
Understanding your warranty is imperative. After all, you can inadvertently void your warranty if you don’t read the hammer’s manual.
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.