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Machinists always have to engage in a lot of drilling. Apart from drilling into woods and glasses, they often drill through-hardened steels. Each of these is a different type of material, so the drilling process and bits are also different. Honestly speaking, drilling through hardened steel is much more difficult than it seems. To drill through steel, you need both the proper knowledge and appropriate tools. Also, you need to maintain proper safety because the drill bit may break due to excessive rotational force and the small steel particles may cause injuries.
Therefore, in this post, we have discussed the methods of drilling through hardened steel. We have also mentioned some tips that will help you to execute the steel drilling process smoothly.
Method 1: Using A Drill Machine
A drilling machine is a versatile tool as it allows you to drill through a variety of materials. In addition, it is easy to carry around and not too complex to operate. Corded or cordless, regardless of the type of drill machine, they all show equal proficiency. So, you can use a drill machine for hardened steel, but you need specific drill bits to accomplish the task.
There are two types of drill bits that you can use – titanium-coated drill bits and cobalt drill bits. Cobalt drill bits are specialized to penetrate materials such as cast iron or titanium. These drill bits are a mixture of steel and 5%-8% of cobalt. It’s more expensive than other types of drill bits. However, you can use titanium drill bits on metal but cobalt bits perform better. So, even though it’s a more expensive option, it’s wise to go with a cobalt drill bit.
Before you start drilling, you need to maintain some safety precautions. Wear gloves and goggles to protect yourself. You also need the following tools to drill through hardened steel – clamps, a marker, a hammer, a center punch, a working surface, etc.
The process of drilling through hardened steel with a drill machine goes like this –
- First, place the steel on a surface and secure it using clamps. Tighten the clamps firmly so that the steel doesn’t move while drilling. To prevent scratches, you can also use stir sticks between the steel and the clamp.
- Once your steel is secured, you need to mark the spot where you’ll be making the hole. Use a permanent marker or pencil and mark the spot with a dot.
- For efficiency, you should create a dent in the marked spot. Take the center punch and place its tip on the target. Then, gently hammer over the center punch to create the divot on the steel surface. You can also use a nail instead of a center punch. This dent helps to prevent slippage and makes a hole so that you can drill accurately.
- Pick a sharp cobalt drill bit to use over hardened steel. Cobalt drill bits will let you make plenty of holes. But ensuring the sharpness is a must because drill bits with damaged tips struggle to penetrate through metals and don’t give a smooth finish.
- Start drilling with a half-sized drill bit than the actual size you need. So, if you need a hole of ½”, start with a ¼” drill dit. Using smaller bits makes it easier for larger drill bits to create holes efficiently.
- Then use the actual drill bit to enlarge the hole. Make sure not to put pressure on the drill and let it work at its own pace. However, if you need a really big hole, use three or four different size bits before using the final size bit.
- Once the penetration is done, take out the drill bit slowly. The drill bit gets hot during the drilling, Thus, if the drill bit is not removed steadily, it may break or bend. Wait 5 minutes for it to cool down before taking the drill bit out.
- After the hole is successfully made, clean the particles from the steel surface. Lastly, use a metal rasp to smoothen the edges to complete the task.
Method 2: Using A Drill Press
A drill press is a heavy-duty tool with a motorized mechanism for boring holes in wood and metal. Just like corded or cordless drills, you can use various drill bits on a drill press. But using cobalt drill bits is the best option. You can consider it as a large drill machine with more power.
The tools required for drilling with a drill press are the same as it is for a drill machine. In fact, except for some minimal changes due to the mechanism, the drilling procedure is also the same.
- Lay your hardened steel on a surface and mark the area where you want to drill. Use a marker or pencil to indicate the target zone.
- Use a center punch or nail to make a dent in the marked area.
- The drill bit you’ll be using should have a durable shank. Also, the flutes of a drill bit should be clean so that it can take out the debris easily. Again, the tip should be sharp enough to drill smoothly. Attach the drill bit to the chuck of the drill press and tighten the screw.
- Now place your drilling subject on the drill pressboard and use a clamp to secure it. It’s important to clamp the item, otherwise, it may move while drilling and may become unusable.
- Then set up the drilling speed and table height. As you are working on a metal surface, it’s advisable to run the drill bit at a slow speed.
- Apply lubricants such as 30-weight oil, water spray, and oil on the steel, then turn the drill press on.
- After that, you need to complete the drilling process gradually by slowly pulling down the lever. When your drill bit has pierced the other end of the steel, you need to pulse it a couple of times so that the finishing is smooth.
- Wipe away all the metal remains and lubricants with a cloth. Be careful while doing so, because the shrapnel might hurt your fingers.
Tips For Drilling Into Hardened Steel
As we said earlier, drilling through hardened steel is a challenging task. While drilling, there are a lot of things you should maintain to get the perfect hole. However, a small mistake can ruin your entire project. So, here are a few tips that will help you through the task.
As steel or metal is dense than wood, strong drill bits are required to drill through these. Cobalt drill bits are able to penetrate extremely tough surfaces because they have tungsten or molybdenum alloying. As a result, they are perfect for making holes in metal.
Control The Heat
It is very important to control the temperature while drilling. So, lubricants should be applied to the metal surface. Lubricant oil will prevent heat that is generated from friction. Also, the Drilling speed should be low when drilling on metal surfaces. Slow drilling produces less heat and minimizes the possibility of overheating. To reduce further heating, manufacturers apply titanium nitride coating on drill bits, which increases the bit’s heat resistance.
Control The Vibration
Drilling through a steel surface causes a lot of vibration because metal is a dense material. Vibration can cause partial or complete damage to your workpiece. So, you should use clamps to keep your workpiece stable.
Use Sharp Tools
Using sharp drill bits increases the efficiency of drilling. It helps to prevent excessive heat and vibration. Always sharpen your drill bits before using them. However, if your drill bit is eroded, then you should invest in a new drill bit set.
Maintaining safety during drilling is mandatory. Regardless of the material, drill bits are prone to breakage and the broken part can injure you. In addition, the amount of debris produced during steel drilling can cause long-term problems if they are blown into your eyes, nose, or mouth. So, you should wear goggles, gloves, aprons, and earbuds while drilling.
The toughness of hardened steel makes drilling extremely difficult. Hopefully, this post will help you to drill perfectly through any hardened steel and the tips will help you to get a quality outcome from your project. Also, don’t forget to maintain safety while drilling.