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How do you bend EMT offsets? #44030
10/26/04 04:25 PM
10/26/04 04:25 PM
C
CTwireman  Offline OP
Member
Joined: Feb 2002
Posts: 840
Connecticut, USA
When I first learned to bend EMT I was taught the "guess and bend" method for offsets, and didn't believe in using tables and formulas.

The person who taught me would bend an offset, check it, bend it again, check it, and usually by the third time it would fit.

Suffice it to say it drove me nuts to do it this way, especially on old work fire alarm jobs that needed lots of offsets and multiple bends. It was extremely frustrating. [Linked Image]

Recently, I've learned the Benfield method in school and find it to be far more precise. I can now bend a perfect box offset every time, which is very satisfying! [Linked Image]

How do you do it? Any tips for making nice bends?

Peter


Peter
Work Gear for Electricians and the Trades
Re: How do you bend EMT offsets? #44031
10/26/04 04:34 PM
10/26/04 04:34 PM
R
Ryan_J  Offline
Moderator
Joined: Aug 2003
Posts: 1,374
West Jordan, Utah, USA
Box offsets I always eyeballed.

Other offsets I measured and bent with 30 degree if I could, 45 if I had to. Once in a while I would eyeball an offset.


Ryan Jackson,
Salt Lake City
Re: How do you bend EMT offsets? #44032
10/26/04 04:57 PM
10/26/04 04:57 PM
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
After fooling around with "eyeball bends" I came to the conclusion my eyeball wasn't very good. I'm a beliver of doing the math & laying out the marks correctly, much faster and, if you are doing multiple runs, then all bends look alike.

I prefer the no brainer 30 degree offset for bends up to about 6". Checkpoint makes a level that has a 30 degree bubble & the level has magnets that are strong enough so the level doesn't fall off the conduit.

Tom


Few things are harder to put up with than the annoyance of a good example.
Re: How do you bend EMT offsets? #44033
10/26/04 05:05 PM
10/26/04 05:05 PM
H
hbiss  Offline
Member
Joined: Dec 2003
Posts: 886
Hawthorne, NY USA
I use a Greenlee offset bender for 1/2" EMT offsets into 1900 boxes and such. Takes less than two seconds and they are all exactly alike. They used to have one for 3/4" but I haven't seen it lately.

For other depth offsets and saddles I use the Benfield method also, although I'll admit that if I'm in a hurry and only have one to do I'll eyeball it.

-Hal

Re: How do you bend EMT offsets? #44034
10/26/04 06:31 PM
10/26/04 06:31 PM
C
CRM  Offline
Member
Joined: Feb 2004
Posts: 74
Alberta Canada
I do box offsets by eye, but for larger offsets, I was taught a different way. However deep your offset is, multiply that by two and thats how far apart your two marks go, then make both your bends using the 30 degree mark. It works perfect every time. For example if you want a 6 inch offset, put your two marks 12 inches apart then use the 30 degree mark to bend them.

Re: How do you bend EMT offsets? #44035
10/26/04 07:24 PM
10/26/04 07:24 PM
H
hbiss  Offline
Member
Joined: Dec 2003
Posts: 886
Hawthorne, NY USA
I was taught a different way. However deep your offset is, multiply that by two and thats how far apart your two marks go, then make both your bends using the 30 degree mark.

That's the Benfield method, if he could lay claim to something that's commonly done.

-Hal

Re: How do you bend EMT offsets? #44036
10/26/04 07:29 PM
10/26/04 07:29 PM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,264
Fullerton, CA USA
I use the guesser on box offsets, and math on all the rest (BTW, the 30° on a Benfield is when the handle is straight up & down).

Greenlee "Little Kickers" are pretty cool, but bend a little too deep for most of the boxes we use. Also, they stick sometimes, and you have to rap them on the floor to get the EMT out.

By far the easiest box offset is a Minerallac...S [Linked Image]

Re: How do you bend EMT offsets? #44037
10/26/04 07:29 PM
10/26/04 07:29 PM
P
Peter  Offline
Member
Joined: Jun 2004
Posts: 92
San Diego
This is dear to my heart. An important consideration when running conduit is the realization that at some point in the future you will have to pull wires into it. Therefore steps should be taken to ease this impending task. For instance, consider using 22.5º degree bends instead of 30º. Or even better use 10º bends if you can get away with it. The formula for 22.5º is multiply by 2.6. For 10º use 6" for every 1" of desired offset.
Another thing to try is what is known as the super bend -- that is using a larger radius than the standard one shot. This is for 90º. To make it you use your bender like a hicky -- you advance it in small steps and bend the tube at small angles at each step.
45º bends are a killer.
Try to plan your runs to minimize the degree count. For instance instead of 90ºing up out of a box, instead use a 12" offset. This will save 30 to 45 degrees.
If done properly, it should be possible for one man to push the wires in [solid] instead of two to push and pull and chatter.
~Peter

Re: How do you bend EMT offsets? #44038
10/26/04 07:32 PM
10/26/04 07:32 PM
A
Active 1  Offline
Member
Joined: Feb 2003
Posts: 687
Grayslake IL, USA
I eyeball box offsets. Biger than that it's the bandfield method. Most of time 30 deg. If you have a newer ideal bender 30 deg the handel is strait up. I don't look at the 30 deg mark on the head just that the handle is strait up. I stamped the multipliers on top of the bender head for when my brain can't think in the morning. Anyone use those little kickers?

Re: How do you bend EMT offsets? #44039
10/27/04 12:39 AM
10/27/04 12:39 AM
S
sparkync  Offline
Member
Joined: Oct 2002
Posts: 830
NC
Here's a website that has some pretty good information on pipe bending. When you get the main page, go to conduit bending page.
www.porcupinepress.com/index.html

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