Stainless steel is a strong, durable metal that is harder to drill through than other materials, such as aluminum and copper, so you can’t use just any drill bit you have lying around your workspace.
To drill stainless steel, it is necessary to purchase a quality bit that is just as rugged as the metal it works on and can withstand high temperatures and extremely fast speeds.
If you are looking for the best bits to use for an upcoming stainless steel project, look at these criteria to help you out.
Type of Drill Bits Best For Stainless Steel
If you are working on a project that requires drilling into stainless steel, there are a few specifics to consider when choosing a drill bit perfect for the job.
Below are the credentials your drill bits must have to successfully and correctly drill through stainless steel.
Material Type (Alloy Steel and Cobalt Blend)
The type of material your drill bit is made from is critical. This will ensure you achieve a precise and clean cut without damaging your hard metal or the bit itself.
For stainless steel, it is highly recommended you use an alloy steel and cobalt mix with around 5-8% of cobalt present (the more cobalt, the longer your edges stay sharp). This hard metal is considered a “high-speed” steel made for cutting, drilling, tap and die, etc.
Cobalt bits are considered construction bits because they are extremely strong and durable and improve the heat resistance of your tools.
Other “construction” bits in the high-speed steel class, including titanium nitride and black oxide metals, can also get the job done right.
Bit Size (1/16”-3/8")
The size of your bit will vary depending on the hole you are attempting to drill. However, ideally you want to keep the bit size between 1/16 to 3/8 inches. If you go smaller than that, you stand the chance of breaking the bit, and any larger can become complicated.
Flute Type (Spiral)
The flute on a drill bit is the sharp cutting edge that pierces the metal. When working with stainless steel, a spiral flute is better than a straight one or any other option. These flutes work best because they offer a higher level of precision with a quicker chip removal rate.
Length (Short, Long, Extra Long)
When using a drill, the length of your bit should accommodate the thickness of the stainless steel you are drilling through. There are three main sizes when it comes to this type of drill bit which is:
- Short: Less likely to break
- Long: Suitable for most tasks
- Extra Long (Jobber): Provides higher cutting and drill precision
You can use each of these bits for various drilling jobs, but choosing the correct length will give you a cleaner outcome.
Angles (118° & 153°)
A spiral drill bit is created with chiseled edges that wrap around the cutting portion of the tool. These edges are designed with angles that bite into the metal more accurately and smoothly.
The best angle for stainless steel drilling is 118 and 135 degrees. This is also the standard size for most drill bits. This angle is ideal as it reduces the thrust needed to cut through the material.
Keep Your Drill Bit Intact While Working on Stainless Steel
A common issue many people have when drilling stainless steel is how quickly the bit can become dull or break. Because stainless steel is such a tough material, this will occasionally happen, no matter what you do. However, there are many different things you can do to extend the life of your bit.
Grab a Can of WD40
Stainless steel is famous for overheating and creating “work hardening.” This is when the metal at the bottom of the hole gets hard, eventually burning out your drill. A lubricant like WD40 can help keep the bit and your material cool, avoiding that issue.
Avoiding “dry drill” can also extend the life of your drill bit. Dry drilling will wear down the blades' sharp edges, making it nearly impossible to cut smoothly or, eventually, at all.
Keep Your Drill Straight
No matter what type of bit you are using, the angle you hold the drill can affect the hole's outcome or the bit's condition.
Because stainless steel is so strong, holding your drill at the slightest angle can create an oblong cut or snap the bit. Hold your drill as straight as possible when drilling this material and avoid any side pressure.
Keep Consistent Pressure
Obviously, you will need to use considerable pressure when drilling into a piece of stainless steel material. But you mustn’t apply too much. There is little wiggle room regarding the force required to drill through hardened steel.
If you apply too much pressure, your bit will not have enough time to cut its way through and can snap. However, if you don’t use enough pressure, the heat conducted between the bit and metal will get too hot and can cause significant damage to your tools and the material.
So, what's the best option? When drilling stainless steel, apply ample force and keep an eye on the chips coming from your cut. If they look like metal spirals, your pressure is perfect; if it looks dusty, push a bit harder.
Hand Drill vs. Drill Press Bit Type
Many people ask if there is a difference between the type of bit you should use when drilling with a hand drill or drill press when working with stainless steel.
The quick answer here is no. While drill presses can often tackle larger holes compared to hand tools, the type of bit you use shouldn’t differ in composition, flute, angles, and the pressure needed to make a clean cut.
Summing Things Up
When preparing to work on a project that requires drilling into stainless steel material, you must use a bit designed for the difficult task. Look at the information above to help you pick the right drill bit, reducing the chances of damage to your tools and the material you are working on.