What is My Wire's Circumference

by Dale Armstrong

I want to use my Dremel rotary tool to twist wire. There is a chuck available that takes items with a circumference of 1/32 inch to 1/8 inch. How can I tell the circumference of a wire to know if it will fit in the chuck?

-Rebecca in Chelsea, Michigan

Well, if you need to find the circumference, we'll need to do a little math. Don't worry, it'll be easy! First, visit our Wire Charts page (in Education section), and scroll down to find the Wire Gauge Conversion Table, which converts wire gauge sizes to inches and millimeters.

That chart will tell you the diameter of your wire; for example, a 20-gauge wire is 0.0253 inches in diameter. If you only need the diameter, you can stop here. If you need to find the circumference of the wire, take the diameter and multiply it by pi (3.14). Therefore, the circumference of a 20-gauge wire is about 0.0794.

You said that your chuck will take items 1/32 inch to 1/8 inch in circumference; that would be 0.03125 to 0.125 inches in decimal form. Because the circumference we found is between those two numbers, you should be fine to twist 20-gauge wire with this chuck. You can find other gauges that will work by using the same formula: Circumference = diameter x 3.14.

I will warn you though, that even using a variable-speed Dremel on the slowest setting can be way too fast to twist most smaller gauged wire, causing it to break. I'd recommend one of our Automatic Wire Twisters instead. Good Luck!

P.S.: To speed up your circumference calculations, I found a calculator here. Simply put in your diameter in the diameter box (the middle one) and click "Solve Others." This will provide you with the circumference as well as the area.

Answer contributed by Dale "Cougar" Armstrong


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  • Category: General Education
  • Technique(s): Design