How do I bend EMT conduit to a broader radius?

Question

I work a lot in EMT conduit. I have a 1/2" conduit bender that bends to a 5" radius, and a 3/4" conduit bender that gives a 6" radius. I also find bent pieces of conduit around the lodge that have a somewhat larger radius than that.

Suppose I want a larger radius, say because a 12" or 18" radius will suffice in my application, and would make pulling easier. Or in one case I need a larger radius (ceiling line to ceiling line in a corner) to avoid blocking a conduit body (wall corner to ceiling line) that will be effectively under the radius. Is that possible and how can I do it?

Answer 1

Using the same hand-bending tools you already have, you can approximate a larger bend radius by leaving short sections of straight conduit in between multiple bends. Below is a picture showing the minimum radius bend you currently achieve with your hand tool (picture on top) and then using three segments of bending coupled with two straight lengths to approximate a larger radius (picture on bottom).

My example in the second picture only shows 5 segments since the picture was made relatively quickly in paint, but the more interspersed bent/straight segments you have, the closer you will get to approximating a true circular radius. However, maybe you don't truly need a semicircle in all cases and just a few segments would do the trick.

Other alternatives I can think of include:

1. Trying to create your own hand tool for achieving common bends (if you're bending the same larger radius often -- perhaps something like an 18" car rim would work)

2. Investing thousands in a pipe bender that can handle conduit and do very smooth arbitrary bends.

Answer 2

I need a larger radius... how can I do it?

• Find a robust sacrificial round object of suitable diameter to achieve your desired bend radius, you can call it a form post
• fill the conduit with sand, I use masking tape to contain the sand whilst bending
• secure the conduit (how you secure it will depend on where you want the bend and what you are using as the form post)
• bend the conduit by hand around the form post; look ma, no kinks

Answer 3

You will have to do multiple bends. Say 3, 30° bends or 30, 3° bends. There is a formula to figure out how much space to put between them. It goes as follows;

1.57 • radius ÷ #of bends

So 1.57 x 12 ÷ 30=.628

Therefore if you mark out a piece of pipe with 30 marks that are spaced 5/8" apart and bend on those marks to 3° each you will achieve a 90° bend with a 12 "radius.

Answer 4

You can also freehand it. just bend a little bit and work your way down bending a little bit just not all the way to the 90 degree stopping point on the Bender! I did these free hand with the Bender handle resting against the ground