How to Drill Stainless Steel

When you first try to drill through a piece of stainless steel material, you will see something strange. No matter how hard you put pressure on the drill and how fast the bit is spinning, you will be not able to drill that piece of metal unless you try a different method.

If recently you tried to deal with such metal and failed, it's not your drill machine's fault for sure; neither, it's the bit. However, drilling stainless steel is quite simple, it's even easier than drilling more tough and hard metals.

But how you are going to make it to the other end of a stainless steel material?

Well, this article is going to reveal the secret along with all your questionnaires regarding why you are unable to cut a hole through such thin metal.

Understanding the Properties of Stainless Steel

It’s always better to first know everything about your enemy before you battle him face to face. As the issue is how to drill stainless steel, it would be better if you have some basic knowledge about the metal.

Stainless steel is a comparatively soft type of metal at its initial condition. This metallic material is well-known for its special purity. There are two types of steel; alloyed and unalloyed. Stainless steel is an alloyed type of metal.

This metal consists of alloy elements such as niobium, titanium, and chromium. Chromium is the reason why your stainless steel materials don't get rust and corrosion.

The element creates a protective layer on the surface and protects the metal from damaging while contacting water and moisture.

The steel materials that we use outdoors are mostly made of stainless steel, and these materials are exposed to weather elements.

This metal is more durable than other metals due to corrosion-resistance. It is also resistant to heat as well. Although you can weld the metal without any issue, you will face difficulties while cutting it.

As the metal requires minimum maintenance and is recyclable, people mostly prefer getting stainless steel materials.

Why is Stainless Steel More Difficult to Cut than Other Metals?

Most people when they first try to drill stainless steel, and after they fail, they think stainless steel is a tough metal. So, to drill through such hard metal, the drill machine must be run at high speed, or it will take forever to cut a hole. Then, they try to drill even harder but still are unable to drill through it.

Even though stainless steel is relatively a soft metal, it tends to harden when it is exposed to heat. So, if you drill stainless steel at high speed, it gets even hardened due to the heat factor. And that’s why it gets extremely tough to drill through.

How to Drill Stainless Steel Successfully

Cutting through stainless steel requires quite less effort than other metals. For this operation, you will need;

  • Power drill with adjustable speed
  • HSS or Cobalt (HSCO) drill bit, both will do the work
  • Lubricating oil or WD-40
  • Safety goggles

Safety First

Drill work can lead to some serious injuries. So, make sure no such thing might get caught around the bit such as long hair, long clothing, etc.

Don't forget to wear safety goggles. The stainless steel that you are about to drill should be put on a material that cannot be damaged by the bit.

Don’t drill putting the metal on your lap and drill towards it. To prevent injury, the surface should be clamped down properly; it should not spin, move or lift up while drilling.

However, I don’t recommend using gloves. Because it can be entangled in the drill if there is an extreme force, speed, and rotation which pose a high risk of breaking the wrist or finger.

The Bit Size Needed for Drilling Stainless Steel

If the steel you are about to drill on, is less thick than 3mm, a single bit is more than enough to make the desired hole.

However, if the steel is thicker, you need to initially drill with a bit of half the size of the hole's diameter that you are about to create. Then attach the second bit for completing the drill work.

For example, if you want to create a ½ inch hole, then you would need two bits of a ¼ inch each. When you are done with the first ¼ inch bit, then bring the second one and drill the rest of the way.

Start Drilling

Now, select on which part of the steel you want to make a hole, and mark its position. Nonetheless, if there is a chance that the swarf can damage its surrounding area, using heavy-duty tape is recommended to prevent the surface from scratching.

Now it’s drill time. Make sure the workpiece is stable and well-secured. Moist the area you want to cut the hole with lubricating oil. If you prefer using coolant, use per the manufacturer's instructions.

No matter what type of lubricating oil you use, be sure that the amount is sufficient to have good contact between the steel and fluid.

Then put the bit tip onto the punched hole and slowly start drilling by pulling the trigger. Go slow, don’t speed up; otherwise, it will make the stainless steel surface hot and harden.

Nonetheless, if you go slowly, you will see short length swarfs smoothly exiting from the hole in a helical shape.

It is the best indicator that you are drilling with proper speed and putting necessary pressure. The stainless steel doesn't get hot that much when you drill slowly and allows you to cut the desired hole.

Thicker metal will require you to switch between the bits until you finish off the hole. While drilling, frequently add lubricating oil to make the surface less warm and prevent the swarf from making a mess.

When the hole has been created, and you are done with the drilling, don’t touch the bit; it will still be too hot to burn your skin. Wipe of the lubricating oil as well the swarf.

You will notice that the back of the hole is fairly rough. If it’s something bothers you, use a metal file to smoothen the ragged edges. But be careful regarding the hole, or you will end up damaging it accidentally.

What Type of Drill Bit Should You Use for Stainless Steel?

There are different types of drill bits which are suitable for cutting holes through stainless steel. However, choosing a perfect one will make your task easier and give you the best results.

High-Speed Steel (HSS) bits are used for drilling soft materials such as stainless steel, plastic, and wood. However, titanium nitride reduces friction and doesn’t allow the heat to hardening the operation.

Therefore, due to that fact, it’s highly recommended to use an HSS bit with TiN tipped. It reduces the chance of crater wear and flank as well.

Cobalt (HSCO) is an upgrade of HSS. These bits are mainly made of steel alloy and have cobalt content of about 5-8%. Due to cobalt content, parent alloy maximizes its strength as well as heat resistant properties significantly. These are two major considerations for drilling through stainless steel.

The drill bit doesn’t allow heat to increase and reduce work hardening rate on stainless steel properties. It also protects the bit from breaking and flanking as well. Such drill bits perform great while drilling through stainless steel as well as harder material.

Tips for Drilling Stainless Steel

When you drill stainless steel, surely it will get harden quickly. That’s because when the bit spins and starts drilling, it produces heat. Due to the heat, the steel surface gets even harder and becomes difficult to drill through.

Here are some useful tips to successfully drill stainless steel metal while reducing work hardening;

  • Always keep the bit cool while drilling. To do that, you will need to use lubricating oil/coolant, a lot of it. If you want to drill more efficiently, consider getting a tapping fluid and proprietary cutting that will reduce the friction while drilling.
  • Keeping the bit properly lubricated will increase the work efficiency, provide a well-drilled surface, and prolong the bit's lifespan.
  • Use a three corner pyramid punch to reduce the risk of slipping the drill bit off the drilling point. It's highly recommended if you are drilling in a small steel surface.
  • Don't go at high speed. It will make drilling even harder. Always go slow while cutting through holes. Drilling at low-speed cuts hole even faster.
  • Using cobalt (HSCO) drill bit is recommended to drill stainless steel; as the bit provides great performance against stainless steel by not allowing too much heat to produce.
  • Don't underestimate using safety gears. Wearing protective goggles is a must. However, as far as wearing headphones are concerned, it's up to you. If the diameter of the steel is thicker or you need to drill multiple plates of steel, then you should wear a headphone.

To Conclude

By following the above-mentioned guidelines, you will be able to easily drill through any stainless steel material. The two major things are, to choose a suitable bit and to drill slowly.

 Don’t just focus on drilling, take precautions and wear safety gears when you perform the drill work.

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