Trouble bending box offsets in EMT

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Old 11-16-16, 08:59 AM
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Exclamation Trouble bending box offsets in EMT

I'm trying to bend box offsets in 1/2" EMT and having some trouble getting it right. I understand the basic idea, I'm doing my first 10 degree bend 2.5" from the end of the tubing and the second bend 2.25" from the first. I'm using a Klein bender which doesn't have any obvious damage or defects. I've done a bunch of practice bends, and here's what I'm seeing:

1. The second bend ends up being a larger angle than the first, even though I am careful to do both bends to the 10 degree mark. In other words, the end of the EMT ends up pointing away form the wall rather than parallel to the wall.

2. The long "unbent" part of the EMT which would be against the wall is not straight, but is slightly bent in the direction of the second bend.

I am doing the bends so that the edge of the EMT ends up aligned with the 10 degree mark when I'm not pulling on it, in other words it's at the 10 degree mark after it's sprung back. I think this is how it's supposed to be done (the other option would be to bend it to the 10 degree mark and then when I let go it will spring back and be straighter than the 10 degree mark on the bender, but I don't think that's I'm supposed to do).

If this sounds like a common rookie mistake that anybody can advice me about, I would really love to hear it! Thanks in advance.
 
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Old 11-16-16, 09:38 AM
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Bending EMT is learned by experience. It takes a while to get used to bending it. It's hard to explain actually bending an offset without illustrating it. I just bend with no measurements or marks but it comes with experience. I did find a video from Ideal that may help you.

you tube/watch?v=5rNrEak1K9o
 
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Old 11-16-16, 11:07 AM
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Yeah, I've watched that video and another one that's similar but uses the same Klein bender I have. Maybe I just have to keep practicing, but I am surprised at how badly my bends turn out. Thanks.
 
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Old 11-16-16, 11:13 AM
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I set the bender in one inch from the end and make a slight bend. Slide the EMT approx two inches away, flip the pipe 180 degrees and make another slight bend.
 
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Old 11-16-16, 11:18 AM
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Or use premade offsets. .
 
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Old 11-16-16, 11:30 AM
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Or use premade offsets.
I didn't want to do that -- I thought it would be fun to learn to bend EMT. Yeah, fun.
 
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Old 11-16-16, 12:08 PM
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Keep practicing. Try doing it by sight alone.
 
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Old 11-16-16, 01:14 PM
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I do pretty well with all aspects of electrical installation EXCEPT when it comes to bending conduit. I've watched all the videos, read all the tricks and techniques and even read the Jack Benfield book and I still make far too many mistakes. I do find, however, the more I do in a session the better I get. The trouble is that I bend conduit so seldom that I have a tendency to forget everything I learned between sessions.

As PJ states, practice, practice and more practice. Jack Benfield states that as you learn the "oops" pile gets smaller but never truly disappears.

https://www.amazon.com/Benfield-Cond.../dp/0872885100
 
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Old 11-16-16, 01:35 PM
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I don't do as much conduit work as I used to so you are correct... there is always an "oops" pile.
 
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Old 11-16-16, 01:44 PM
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Furd, that makes me feel a little better.

Here's a crazy idea: as I said the "unbent" part of the EMT ends up being a little bit bent. Would it help to slip a piece of 3/4" black steel pipe over the EMT to keep it straight right up to the bender shoe? I suspect this is a bad idea or I would have already read about it, but I may give it a try. The most it will cost me is a ruined piece of EMT, and I have a feeling that would have happened anyway.

If I can't figure this out I might just buy a used offset bender from eBay and then sell it when I'm done. I will be out the cost of shipping (assuming I can sell it for what I paid), but will probably save lots of time and EMT.
 
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Old 11-16-16, 02:20 PM
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When you state the "unbent" part do you mean the end or in the "run" of the conduit? If it is in the run then you are not holding the bender tight against the floor. You must always have the bender on the floor and your foot on the "pedal" HARD before pulling the handle. If the bender comes off the floor then the conduit will kink. The only exception is a few times when it is utterly impossible to have it on the floor and then you need to have the conduit in your armpit, the bender handle hard against the floor and use all your weight to keep the conduit in the bender shoe.


Where I used to work we had a contractor do most of the new installations on the energy management system. I had asked this man about offset bending tools and he said that he had one but never used it as it didn't fit most of his enclosures. He also said that bending offsets was really easy and he showed me how to do it. He might as well have been trying to teach me to read Egyptian hieroglyphics for all the good it did me. That man could make conduit pretzels. Then again, just about anything looks easy when it is done by a master craftsman.
 
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Old 11-16-16, 02:27 PM
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Everything I have seen about doing box offsets says that they are "air bends," with the handle end on the floor and the shoe and conduit in the air.

The bend I'm talking about is in the "run" of the conduit. It's happening between my armpit and the bender shoe, and it's not a kink. If I lay the "run" of the conduit down on a flat surface I can see that it's not perfectly straight anymore.
 
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Old 11-16-16, 02:43 PM
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It has been at least three, maybe four, years since I bent any conduit so let me see if I remember. I may want PJ or one of the other real electricians to describe it for you.

The initial bend of an offset is done on the floor. As I recall, this is the stub and then you reverse the bender (handle to the floor, braced with your foot) turn the conduit 180 degrees and bend the "kick" with the conduit under your arm. You need to use your hands on the conduit in the shoe and place as much weight on them as possible while lowering yourself in a crouch, all the while keeping a minimal tension on the conduit in your armpit. If you get a slight bend in the run then reverse the conduit again, placing the bend in the center of the shoe and slightly bending it back straight.
 
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Old 11-16-16, 05:46 PM
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Buy a Benfield Conduit Bending Manual. This manual is a standard in conduit bending training.
Buy some conduit and practice
 
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Old 11-16-16, 06:19 PM
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You need to align the bend to the bender. any slight misalignment will show up after the second bend. It can be removed if not too bad.
 
 

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