7

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?

10

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).

enter image description here

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.

6

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
  • 1
    As well as sand and other powders, there is metal sold as Bendalloy brand, for that purpose. – JDługosz May 3 '17 at 4:53
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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.

2

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 groundenter image description here

  • NICE! Looks like art to me. Now pipe propane through that baby, drill holes all along the pipes, put restriction orifices out on the ends, and LIGHT IT UP!!! – Jimmy Fix-it May 4 '17 at 2:25

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