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Uses for a Step Drill Bit in the Workshop or Studio

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I am an artist who is always exploring different materials, tools, and processes.


As an artist and material enthusiast, I am always looking for the next cool tool that I can find useful. Although I admit that sometimes a tool ends up being a one trick horse and I abruptly do an about face to the next one. When I first heard about how great step drill bits where with plastics I got excited. I already knew how they performed with sheet metal but now they had a second use to me. As a third use I figured out the deburring trick on my own just dabbling. With these uses now in mind, I got a set of my own and I wanted to share the uses in one article

Advantages Of Step Bit

The step bit is an awesome tool and essential addition to any workshop. The main advantage of the step bit is have the utility of several drill bits in just one bit. This saves time in having to repeatedly having to loosen drill chuck, change bits, and retighten. This ideal from control panels that need many different sized holes for various components. Another plus, is the lower acute cut angle which makes it easier to drill into softer materials like plastics, aluminum, and brass.

Disadvantaged To The Step Bit

With the step bit being such a handy addition to the tool box, its hard to imagine that there would be disadvantages to them. But there are some characteristics worth mentioning so time and material are not lost. Most step bits work only in thinner stock. The steps in most step bits are only a 1/4 inch or less and therefore only able to work in thinner stock. If one step gets damaged, you must replace the entire tool. The step bit would work up to the damaged step but anything beyond would be inaccessible. Lastly, name brand step bits can come with a hefty price tag but there are several import sets that are good for occasional use for a much more reasonable price. But if you need a step bit every day, do not be cheap and skimp on quality.

Step Drill Bit Set

Set of step drill bits of various sizes and configurations

Set of step drill bits of various sizes and configurations

The Handy Step Drill Bit

If you spend any time in the hardware store or home improvement center, you more than likely have seen a step drill bit in one form or another. You have either seen them individually or in a set. The function of the step drill bit is to have the capability to drill several whole sizes with one bit. What this does is saves a lot of time changing drill bits in the chuck when numerous holes of different diameters. Step drill bits are for drilling into stock that is 1/4 inch and less in thickness.

Types of Step Drill Bits

The step drill that comes in to basic forms. One form is the smaller step drill bit and it is self starting. What that means is that no pilot hole needs to be pre-drilled before using the step bit. The other form is a larger step drill bit usually requires a pilot hole the same size as the smallest dimension on the bit itself.

Types of Materials To Be Drilled With A Step Bit

The most common material for using a step drill bit is sheet metal 1/4" and thinner. Depending on the step drill bit used, it could be material 1/8" thick or thinner. With metal, a pilot hole is necessary. Once pilot hole is drilled though, the step drill bit can be operated at high speed and it won't catch like traditional twist bits.

Step drill bits are also recommended for many plastics sheets as well. Most twist drill bits made for wood and metal are of the configuration with the cut angle of 118 to 135 degrees and they have a positive rake angle on the cutting edge. What this does is remove material by scraping. The positive rake angle helps draw the drill bit further into the workpiece. This is great but very bad for plastics. Plastics have low softening temperatures and this action generates a lot of friction and heat. What happens is the drill embeds itself into the plastic sheet and stress cracks the backside of the hole. Worse, the work piece can stay attached to the bit and spin around vigorously risking personal injury to operator. Step bits on the other hand have tip angles that are 90 degrees or less. Also, there is no rake on the cutting edge of the flutes. Below is a video showing a step drill bit in a drill press drilling into cast acrylic sheet.

Step Drill Bit Drilling Into Cast Acrylic Sheet

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Holes Drilled In Acrylic Sheet With Step Drill Bit

Two holes drilled into cast acrylic sheet with a step drill bit.

Two holes drilled into cast acrylic sheet with a step drill bit.

Deburring Holes

Typically when using a twist drill bit to drill a hole, especially in metal, there are often burrs on the perimeter. The same is true with step drill bit but to a lesser extent. These burrs can be sharp and present a cut and abrasion hazard. Also, they mar the surface of the work piece which can interfere with later assembly of components.

Normally, a rat tail file or a power grinder with a wire wheel or flap disc would be used to deburr. If you already used the step bit to enlarge a hole, then the more expedient thing to do is use the bit to deburr also. You simply use the edge of the next size from the hole you just drilled. This produces a nice clean chamfered edge on the hole. Consult the video below.

Removing Burrs From Holes With Step Drill Bit

Step Drill Electrical Enclosures

Step drill bit making large holes into a metal enclosure.

Step drill bit making large holes into a metal enclosure.

Electrical Work

One very big application for the step drill bit is in the electrical and electronic industry. Sometimes holes of considerable diameter have to be made on enclosures to accomodate lights, buttons, switches, and sockets. Also, holes may need to be added for routing cables and cable bundles. Although junction boxes usually have holes ready to be popped out, step drill bits are still needed for custom end user modules and control panels.

Step bit usage

© 2017 Jason


Jason (author) from Indianapolis, IN. USA on September 19, 2017:

Thanks I appreciate that. I was astonished that nobody has written about using the step drill bit.

RTalloni on September 18, 2017:

Nicely done and useful article. Learning about step drill bit uses in a practical, straightforward format is helpful.

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