What is a Step Drill Bit Used For? (5+ Popular Uses)

Step drill bits stand out in some tasks where other drill bits simply won’t work.

They function exceptionally well though you cannot use them in objects thicker than their step heights. They are very handy tools for drilling holes in plastic and metal sheets.

In general, step drill bits are used to:

  • Drill holes through plastic and metal sheets.
  • Enlarge existing holes
  • Help to smooth edges from holes – making them neat

I will go through these uses more below.

1. Cutting Holes in Thin Metal

For this type of work (drilling holes in metal sheets), a straight-flute step drill bit is the best choice. The drill bit does not relay torque to the metal sheet. The metal sheet remains untwisted after the drill bit punctures the metal.

However, if a regular step drill is used on thin metal sheets, it pulls the sheet. That results in a somewhat triangular hole that can be eliminated using uni bits.

Contrastingly, step-drill bits are perfect for drilling holes in thin metal sheets. You continuously progress along the steps until the hole attains the desired size.

Metal doors, angle irons, steel pipes, aluminum channels, and other metal sheets can be drilled effectively by a straight-flute step drill. Anything whose cross-section goes up to 1/8 of an inch is drillable by the step drill bit.

The major downside is that you cannot use the uni bits to drill a uniform diameter hole deeper than the step height on the drill bits. The diameter of most drill bits is limited to 4mm.

2. Cutting Holes in Plastic Materials

step drill bit cutting holes on plastic
Video | bigclivedotcom

Another important application of step drill bits is drilling holes in plastic sheets.

Acrylic and plexiglass plastics are popular materials that require drill bits to cut holes. In practice, step-drill bits prove crucial in this task as opposed to other traditional twist drill bits.

Traditional twist drill bits create cracks once the bit punctures the plastic sheet. But step-drill bits overcome the crack issues. That makes the hole neat.

Note: When puncturing brand plexiglass or any other plastic sheet, leave a protective film on the plastic sheet while cutting the holes. The film will protect the plastic surface from scratches, accidental bumps, and nicks.

3. Enlarging Holes in Plastic and Metal Sheets

Perhaps you have just made the holes through your plexiglass or a thin metal sheet, and they are too small, or there are existing holes in your metal or plastic sheet that cannot accommodate the screws or bolts. You can use a step drill bit to instantly increase the holes’ size.

Again, step-drill bits are quite useful for the task. Each chamfered step of the step-drill bit has a diameter larger than the one before it. That means you can keep drilling until you reach the desired hole measurement.

The process is quick and easy. Besides, the step-drill bit continuously removes the burrs while cutting through the material in question making the hole neat.

4. Deburring Holes

Burrs or raised edges tend to disfigure holes. Luckily you can use drill bits to remove the unpleasant burrs on the holes in your plastic or metal sheet.

To deburr edges of the hole, proceed as follows:

  • Grab your drill bit and turn it on
  • Then, lightly touch the beveled surface or edge of the next step to the rough surface
  • Repeat the process on the other side, and you will get a clean and perfect hole

5. Drilling Holes in Carbon Fiber

To drill a hole in carbon fiber, many people use carbide-tipped step drill bits. They are well-suited for the job. They create neat holes without damaging the fiber. Again, you can make holes without swapping the drill bits.

Downside: Drilling carbon fiber harms the drill bit in use – the bit will dull relatively faster. I recommend replacing your drill bit regularly if you are working on a big project. However, if it is just a one-off situation, it will have minimal or negligible damage to your bits.

Other Uses of Step Drill Bits

Over the years, drill bits have been incorporated into other fields and spheres of work: automotive industries, general construction, sanitary engineering, carpentry, and electrical work. (1, 2)


You can use a drill bit to cut holes in wood thinner than 4mm. Do not drill larger blocks with drill bits. Also, ensure you use a compatible bit.


A step drill bit is a popular tool for electricians. With the drill bit, they can cut correct-sized holes in various panels, junction boxes, and fittings without changing the drill bit.

Take a look at some of our related articles below.

(1) sanitary engineering – https://www.qcc.cuny.edu/careertraq/
(2) carpentry – https://www.britannica.com/technology/carpentry

Video References

Gregg Distributors LP


Dave the Woodworker

Kevin Caron, Artist

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About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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