So you’re worried about how to drill holes in metal? Worry no more! Although there are a few different techniques and ways to do it, they’re easy after a little practice.
Although I discuss drill bits in more detail further down, for a lot of metals, all you actually need is a standard HSS drill bit. With that said, factors such as how many holes and how often you drill metal, along with the type of metal you are working with need to be considered.
So let’s get stuck in.
Contents (Jump to Topic)
Different Types of Metals Commonly Drilled
As you are probably all aware, metal types vary greatly in hardness, strength, malleability, and toughness. And, because of this, different drilling methods such as applying the right pressure and correct speed, are required.
Here are just a few of the common metals you may come across:
- Steel – Steel is a hard metal that requires a hard drill bit such as a cobalt bit. Use gentle and steady pressure and a slow drill speed.
- Carbon (Hardened) Steel – Another hard metal requiring a cobalt drill bit. Again gentle steady pressure and slow drill speed are required.
- Stainless Steel – Stainless steel has a notorious reputation for drilling. However, you can use a standard HSS drill bit, run the drill as slow as possible (stopping and starting to avoid heat) and apply a strong force to the drill.
- Cast Iron – You can use any drill bit that can be used for metal. However, be gentle and slow as cast iron is a brittle metal.
- Aluminium – Aluminium is a softer metal and can be problematic to drill. The best option is a sharp, high-polished drill bit and a medium drill speed, however, a slow speed is needed for larger holes.
- Copper – Copper is one of the soft metals that a standard HSS drill bit should easily pierce with its center point. Use gentle pressure and slow speed.
- Brass – Brass is a copper and zinc alloy that can grab the drill bit’s sharp edges, a bit with a zero rake cutting edge is best.
What Do You Need To Drill Metal?
Drilling through metals requires a great deal of planning and knowledge of the forces at play. It is not, contrary to common belief, a regular maintenance procedure. Drilling metal requires the use of appropriate equipment and drill bits, as well as knowledge of how to operate the various instruments and recognize when you’re about to get into difficulty.
Here is everything you’ll need to drill metal.
When drilling holes in metal you have tiny pieces of metal shavings and shards etc that will be sent flying into the air. Therefore following the correct safety procedures is really important.
Always wear safety glasses, I can not understate the importance of protecting your eyes. You only have two eyes, don’t go damaging them.
Metal is sharp so wearing heavy leather gloves, or similar, is imperative. Preferably they will be a design that goes high up the arm, if they don’t then cover your arms by wearing long sleeves to avoid cuts.
The Appropriate Drill For The Job
Although any drill is suitable for drilling metal, it does have to be suitable for the task at hand. For example, using a low power cordless drill to drill holes into steel may not be the way to go.
Although it is not always possible or available to use, a pillar drill or drill press is an ideal tool for the job. However, with the right drill bit, any type of combi drill should be up to the job depending on how perfect you need the hole and how thick the metal is.
Having the correct hole diameter is not all that you need to consider. Make sure that you know your metal and the drill bit that is required to drill the perfect holes. If you are drilling steel then a super hard drill bit is required.
However, for softer metals one of the standard HSS twist bits is fine. (I discuss all the different types of drill bits in detail a little further down).
Never ever be tempted to hold the metal with one hand while drilling with the other. Every now and again the drill bit may grip the piece of metal causing it to snatch and spin. This is not only a very serious safety concern, it may also damage your workpiece.
Friction can cause rapid heat build-up and excess heat may harm the drill bit or the material being drilled. By using the correct lubricant and/or cooling agent will avoid this happening.
What Is The Best Type Of Drill Bit For Metal?
When it comes to wood or drilling through brick, the material of the drill bit isn’t too important, but when it comes to metal it’s a different story.
Truth be known, there isn’t one particular type of drill bit that is best for all metals. As I have mentioned above there are different factors that need to be taken into consideration, such as the amount of use and the type of metal being drilled.
High-Speed Steel (HSS) Twist Bits
These drill bits are general-purpose twist bits ideal for metal and can also be used for various materials around the home.
Coated (Titanium) HSS Drills Bits
HSS Titanium bits are harder and will last longer than regular HSS bits, and still include steel at their core. Another great general-purpose twist bit.
Cobalt Drill Bits
These are probably the best for the DIYer wanting to drill through hard metal such as steel. The greater the percentage of cobalt, the more heat-resistant and durable the drill bit is.
Solid Carbide Drill Bits
These are the toughest of them all but are not for the DIYer. They are mostly utilized for production drilling and should not be used in drill presses or hand drills.
What Is The Strongest Drill Bit For Metal?
Although solid carbide drill bits are the strongest drill bit for metal, they are not really suitable for use around the home. Without a doubt, for home use, cobalt drill bits are the best for drilling harder metals.
What Is The Best Drill Bit For Steel?
The best drill bit for steel that I can recommend is the HSS cobalt drill bit. It is an excellent all-rounder and can be used with a wide range of materials as well as hardened steel.
Other Considerations Before You Start
When drilling into metal, heat build-up is a concern. Correct lubrication may help reduce and regulate this, but another element can play a big role in the temperature rise, and that is speed and drilling too fast!
As a result, here are some things to think about before you begin.
Lubrication & Oil
When drilling harder metals, especially stainless steel it is important to keep the drill bit and material lubricated to prevent overheating and keeping the bit cool. This not only increases drill bit life but enhances cutting action, accuracy, and quality.
Using a multipurpose oil such as 3-IN-ONE or motor oil is just fine to reduce friction, although metals such as aluminium, cast iron, and brass should not require lubrication. For very large holes and hole saws using a cutting oil is important.
I often hear the question of ‘can I use WD-40 for drilling metal’? The simple answer is yes, WD-40 can also be used as cutting oil.
How To Drill Through Metal: Easy Step-By-Step Guide
A few specific methods may help you drill clean, precise holes in metal without putting your drill bit through too much wear. When drilling into metal, these are the procedures to take.
Step 1: Make sure you’re safe
Step 2: Make a sacrificial sandwich (Optional)
Making a sacrificial sandwich will aid in achieving a clean hole in soft or thin metals and thin sheet metal. For this, place the metal between two pieces of wood and clamp to a workbench before drilling.
Step 3: Begin by making a Dimple & Pilot Hole
Drill bits tend to stray off as soon as the drilling begins. To avoid this, use a pointed punch (center punch) and a hammer to create a tiny depression in the metal at your drilling mark. Once you have the dimple drill a pilot hole with a drill bit that is smaller than the final hole size.
Step 4: Apply lubricant
If you are drilling into steel that is steel that’s 1/8 in. or more then now is the time to add a couple of drops of your cutting oil or lube.
Step 4: Drill slowly
Most drills should operate at half-speed or slower, if yours doesn’t then stopping and starting the drill can work to keep the heat down. Remember the larger the drill bit, the slower it should spin.
Step 5: If you see smoke, stop drilling
You should immediately stop drilling if you detect smoke as it means you have too much heat. Allow your drill bit to cool down, add a few drops of more lubricant and restart slowly.
Step 6: Clean up the hole
Very often your drill hole will have rough edges, to solve this place a larger bit in the hole and twist it by hand. This works well and saves investing in a hole cleaner.
Remember, drilling holes in metal is not difficult in itself. But, all metals vary and it is important that you understand the material you are working with, along with the drill bits for metal that are available to you.
Frequently Asked Questions (FAQs)
I hope you found this blog helpful and are now reassured that with care and safety in mind you will be able to drill metal like a pro in no time. Here are a few questions and answers about stuff I have not covered fully above but are often asked.
Does heating metal make it easier to drill?
Although heating metal might help soften a metal making it easier to drill you risk undermining the strength and quality of your material.
How to drill a hole in metal without a drill?
If the hole is close to the edge of your piece then hole punch pliers are simple to use, however, this option is only good for thin metals. Another good way to make a hole in metal without a drill is by using a hollow hole punch and hammer.
What is the hardest metal to drill through?
The hardest metal to drill through is steel, especially stainless steel. However, as long as you make sure you have the correct drill bit and know how to drill hardened steel you should have no problems. Using a cobalt drill bit is recommended.
Does metal drilling cause sparks?
Drilling metal should not create sparks when done correctly. Sparks are caused by small bits of metal heating up, when using a cooling agent or lubrication this should not occur during the drilling process.
Which is better, brushed or brushless drill?
Because a brushless drill uses magnets to create energy rather than brushes it avoids creating friction which causes heat. This means that a brushless drill is better than a brushed drill in the fact that it is more efficient, gives better performance, and lasts longer.