Drilling may seem like an easy task and although that isn't an entirely wrong assumption, you need to make use of the right bit in order to make it look easy. Drill bits come in various different forms and designs with each and everyone being able to either do a select number of tasks or specialise in one. Well, what if I told you that there's a category of drill bits meant for drilling through certain thicknesses of metal and other materials. Those drill bits are step drill bits. Sheet metal is the material they're meant to be used on, but these conical-shaped accessories can be used with plywood, drywall and plastic too. Their stair-step profile is what gives the meaning behind their name and also the ability to enlarge holes.
Important Features of Step Drill Bits
Source: hilti.com
Material
Be it just the top part or the whole bit, one of the most popular out there is high-speed steel. An HSS step drill bit is found for sale in almost every trade supply store in the country. HSS bits are the most affordable and can be used on wood, fibreglass, plastic and soft metals.
You also have TiN step bits which are made with a multipurpose coating that helps improve the bit's chip flow which is useful for softer materials. Titanium nitride bits are used at faster speeds thanks to the coating's hardness and heat resistance.
A carbide-tipped step drill bit is best for long drilling activities. You should buy a carbide-tipped step drill bit if you want to drill through tile work and brick masonry. Also, carbide-tipped bits are known to stay sharper for longer.
With a cobalt step bit, you can make holes in materials such as aluminium and stainless steel. But keep in mind that these bits are more brittle but yet they cool down quite quickly so that they can maintain their stiffness at higher speeds.
Size
The size of step drill bits determines, first of all, the size of the hole you'll be able to make and, second of all, how easy it's going to be to drill through the material. Larger bits, despite being seen as more powerful, need a pre-drilled hole in order to start drilling with them. This is because they usually have a blunt tip. Smaller bits are, more often than not, self-starting, meaning they don't need a pre-drilled hole that matches the smallest step on the bit, in order to start drilling.
Uses of Step Drill Bits
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Drill Holes
The most apparent use of step drill bits is drilling holes through sheet metal. But sheet metal isn't the only flexible material step bits can be used on. Acrylic and other plastics such as plexiglass can be at the other end of a step bit.
Enlarging Holes
If you've already made a hole or someone else has before you even knew and it's not as big as you need it to be, you can always buy a step drill bit to enlarge the said hole. For this, to work you need to make sure you get a bit with the right size chamfered step that will enlarge the hole to a size that's suitable for your project,
Deburring & Chamfering
Talking about chamfering, you can do that too with a step bit. Not only that, you can also deburr the edges of a hole. This is done by touching the bevelled edge of the step above the one you used to the edge of the hole. When it comes to chamfering you need to use the same step you do when deburring but you need to cut a bit deeper into the surface of the metal or plastic.
General Construction
When it comes to general construction tasks, a step drill bit for sale is almost always going to be recommended by any employee or shop owner. Why? That's because the steps of these drill bits make them versatile enough to be used for cabinetry, underfloor heating, plumbing fixtures, electrical infrastructure and more.
How to Use a Step Drill Bit
Source: popularmechanics.com
On Metal
1. Thin metal that is no thicker than the height of the bit's steps requires you to first mark the step on the bit that you want to stop drilling at. Then, you must position the metal piece and clamp it down so that the bit is pointing right where you want to make the hole.
2. Before you start drilling though, make sure to add a drop of lubricating oil where the bit will go through the material. This will make the whole process a lot cleaner. Once that's done, start drilling the hole to the depth you've marked on the bit.
3. If you need or want to, you can add a chamfered edge to the hole by tapping the surface around it with the bevel of the step that's sitting above the one you marked.
On Plastic
1. The same steps you took when making holes in sheet metal are made when making holes in plastic materials. But when drilling through plastic you don't need to use lubricating oil.
2. When working with acrylic sheets of plastic you don't need to take off the protective film from each side either. Although this may make the hole look uneven and distorted, it's only when you remove the film that the hole looks perfect.
