Precision EMT Bending

Sep 23, 2026

Uploaded by Franzy

Precision EMT Bending guides readers through creating rigid arcs and circles using thin-wall Electrical Metallic Tubing (EMT). It explains why EMT is preferable to PVC for rigidity, welding, weather resistance, and paintability, and compares prior chalk-radius methods with a more systematic approach. The document covers planning bend size, calculating circumference and “straight length,” using a circumference calculator, and computing developed length for 90-degree arcs to determine spacing for 5-degree bends.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages28

Reading Time1 h 11 min

AccessFree to download

Overview-Background

Before Starting

Circumference calculation

Items Needed

Circumference Calculator

Calculating for the 90 degree arc

Set up

Marking the 5 degree reference

Precision EMT Bending Overview-Background: At some point doing a Christmas display, there becomes a need to have some rigid arcs or circles. These have various uses, from Light Fans, to Mega/RGB Tree Bases, Leaping Light Arches, Mounting Bars for Floods, etc… The potential is unlimited. EMT has specific advantages over PVC based conduit, because it is more rigid, can be welded (very carefully), tapped, screwed, clamped down, it holds up to wind & weather. Plus, like PVC conduit, when prepped properly, it can be painted. Over the years, I have used the method of drawing my radius in chalk on the ground, grabbing my Bender and ad-hoc going to town. Now, this method worked OK, but for me it was frustrating and time consuming. I had no “plan” nor understanding of technique. So I ended up with ovals, helix effects etc… that required a lot of fudging. The results were OK, but IMHO, could have been better. Walter Monkhouse planted the seed for creating this document in talking to him about his ColorMotion Tree, the base he made, and how he made it. I got to thinking that there had to be a better way to approach this. With the help of a good buddy, fellow light crazy, certified electrician and teacher, Pete Peters, he got me bending in the proper way. I felt it was something others would need, and appreciate. My suggestion is to read this entire How-To a few times, review the pictures, then orient yourself to the tools and materials, then start your first project. It takes a project or 2 to really get the feel for how this all works. Before Starting: You first need to figure out the size of bend, arc or circle you require. Then you need to calculate the circumference of that element to determine the “straight length”. This is where the Circumference Calculator on the first page comes in handy. Plug in the diameter of your element, and it provides the other information. For this HowTo: we will be using a 5ft. diameter circle as our example. The calculator gives us a circumference of approximately 15.7 feet. Which means that we will need 2 10ft sticks of EMT to create our circle. We will build this in 2 180 degree halves and join them with our EMT Couplers. Note:1 Copyright Woodinville Wonderland 2016 1 Precision EMT Bending Items Needed: 􀁸 EMT—Electrical Metallic Tubing (thin wall) 􀁩 1/2” -3/4” -1”(Approx $2- $7 per stick) 􀁩 Determine size for your purpose 􀁸 Matching EMT Couplers (Approx $.55 apeice) 􀁸 Conduit Bender 􀁩 2 sizes available 􀁩 1/2” -3/4”(Approx $40) 􀁩 3/4” -1”(Approx $80) 􀁸 Magnetic Protractor (Approx $10) 􀁸 Hack Saw 􀁸 Screw Driver 􀁸 Tape Measure / Steel Ruler 􀁸 Metal File 􀁸 Upright Bender Holder (Optional-see Picture 5 ) Circumference Calculator: 􀁸 [http://math.about.com/library/blcirclecalculator.htm](http://math.about.com/library/blcirclecalculator.htm) Picture 1-Required Tools 2 Copyright Woodinville Wonderland 2016 Precision EMT Bending Calculating for the 90 degree arc: Electricians figure bends in term of 90 degrees. They have a specific formula to calculate the concentric bending of the conduit. That formula is: 􀁸 Radius x 1.57*** , divide by 18 (to get the spacing between bends for one quarter of a circle) 􀁸 The 18 represents the number of 5 degree bends for every quarter of a circle (90 degrees) Let’s take a look at our example, it is best to break this down into inches: 1. 5ft Dia = 60 inches-divide by 2 to get the radius = 30” 2. 30” times 1.57*** = 47. 10” (Developed Length*** of our 90 arc) 3. 47.10” divided by 18 (5 degree bends) = 2.62 4. Putting back into fractions for our tape measure, or ruler, (.125 = 1/8” & .0625 = 1/16”) we attempt to convert back to the nearest 1/16th inch, for this example, we have approximately 2 5/8” between each 5 degree bend. I’ve included a fractions/decimal conversion chart for reference on Page 14 . NOTE: You can calculate for 10 degree bends, which makes things somewhat easier as you have less b

FAQs

Why use EMT instead of PVC conduit for forming arcs and circles?

EMT is more rigid, can be welded very carefully, and can be tapped, screwed, and clamped. It also holds up to wind and weather and can be painted when properly prepared.

How do you determine the straight length needed for a circle?

Measure the element diameter, calculate circumference to find the straight length, then plan the required EMT sticks. In the example, a 5 ft diameter circle uses about 15.7 ft of circumference, resulting in two 10 ft sticks for two 180-degree halves.

What formula is used to calculate spacing for a 90-degree arc?

Use Radius x 1.57, then divide by 18 to get the spacing between bends for one quarter circle. The 18 corresponds to eighteen 5-degree bends totaling 90 degrees.

Sep 23, 2026

Uploaded by Franzy