Best Practices
How to Maintain Rock Tools, Drill Bits, and Drill Steel
When it comes to drilling through hard rock, your tools, bits, and steel are what do the hard work. Properly maintaining them and keeping them in top working order is the only way to complete the job and minimize expensive downtime and delays. To help you out, we've put together some key tips and best practices for ensuring all the components of your rock drills work as effectively as possible on every drilling project.
Match your drill bits to the rock you are drilling
Before you even think about maintenance, you have to choose the right bits for your rock drilling job, and there are several factors that influence that choice:
Material hardness and abrasion resistance—Highly abrasive rock formations can rapidly wear down drill bits. Selecting ones made from strong tungsten carbide that are specifically engineered for high abrasion resistance can substantially increase their operational lifespan.
Bit design—There are various types of bits that are better for different rock types. For example, button bits are effective for drilling shallow to medium depth holes in hard rock, and cross or threaded bits are optimal for penetrating extremely hard rock formations and creating deep holes.
Use the correct feed pressure
In rock drilling, feed pressure is the force applied to the bit as it moves through the rock. If you apply too much feed pressure, then your drill steel can buckle and bind in the hole, stopping rotation, and bringing drilling to a halt. How much feed pressure is required differs based on the material that you are working with. For example, when working with harder rock, penetration is slower and feed pressure should be lowered accordingly. On the other hand, when drilling through softer rock formations, reducing increasing the feed pressure can help drill bits engage and penetrate more effectively.
Check coupling temperatures
Rock drill couplings, also known as coupling sleeves, are components that connect different parts of the drill together and transfer energy between those sections. Couplings are made from high strength alloy steel and are designed to be durable to take on tough conditions. With that said, it is very important to understand the temperature range of your couplings and regularly monitor their temperature using dedicated sensors to ensure they stay within your drill's parameters. If it is too high, then it could indicate that there is an issue with your rig's cooling system, that your drilling speed or feed pressure is too high, or that the coupling is damaged, leading to increased friction.
Don't forget water when collaring
In order to keep your drill from overheating when collaring, it's important to wet the bits and the ground you are drilling into. Water will reduce the amount of friction and lower the temperature of your drill bits, preventing them from becoming too hot. It also delivers the added benefit of minimizing the amount of dust that is produced and thrown up into the air during the initial rock drilling stage.
Regularly inspect your rock tools and bits
Before beginning work each day, we recommend visually checking your drill bits and overall rock drilling rig. Here's what to look for:
- The drill string to make sure threads are not wore out, which can cause breakage
- Missing buttons on your drill bits—Take bits out of service once you are missing two buttons next to each other
- Flat spotting on the drill bit buttons—If the flat spot is on the top of the button, then you're using the correct rotation speed, if it's sloping in the direction of rotation, then your speed is too slow, and if it's sloping in the opposite direction of rotation, then your speed is too fast
Follow a maintenance schedule
Ultimately, properly maintaining your drill bits and drill steel comes down to sticking to a routine. How often you handle specific maintenance activities will vary based on how frequently you're using your rock drilling rig and the type of material you're working with. In general we suggest that you perform these activities regularly:
- Regularly rotate your lead steel to prevent excess wear on one piece of your drill steel
- Clean, change and add fluids, and flush the cuttings from your drill drifter according to the manufacturer's recommendations
- If you will be re-sharpening your drill bit, do it when 1/3 of the carbide is worn off
Utilize a guide tube
When possible, we recommend using a rock drilling guide tube that helps maintain drill alignment and prevent hole deviation. Guide tubes are especially important for jobs that require tight precision and accuracy, such as exploration, geotechnical, and construction projects.
Consider where you're drilling
Before you start rock drilling, it's crucial that you look at the face of the quarry to be aware of any caverns or incompetent rock that could cause damage to your drill bits or get them stuck. Incompetent rock is a less rigid type of rock and more likely to deform than fracture, potentially trapping your bit.
Don't dry fire the hammer when drilling through overburdened
When drilling through the loose upper layers (overburdened) before reaching the solid rock, you should not allow the hammer mechanism to operate without resistance. The drill bit should always be in contact with the material being drilled. Dry firing causes unnecessary wear and tear on the drill components, wastes energy, and can make it difficult to keep control of the drill.
When it comes to maximizing productivity and the longevity of your rock tools, we suggest always relying on Sandvik rock drilling technology. They deliver the most durable, effective equipment on the market. If you have any questions about drill bits, drill steel maintenance, or rock drilling in general, contact our team today!