Emt pipe bending

[Danny89]

Hello guys I'm fairly new at bending emt for offsets and such.

I use the following rules.

10 degree bends equals multiple of 6
22.5 degree bends equals multiple of 2.6
30 degree bends equals multiple of 2.


So this weekend I bought a klien bender bought some 5 foot sticks of 3/4 pipe and tried my hand at multiple offset bends.

Problem I was having was I would always end up with a level offset but 3/4 of an inch too much of a bend. Why does this happen am I putting too much of a bend in it or am I putting too little of a bend in it?

Everytime I do the math for for the distance between my marks. I mark the pipe bend it at the desired line on the bender(30degrees) flip it 180 degrees and bend at second mark...

How do I fix this and become consistent with exactly what I want instead of 3/4 inches higher than I want to be with my offset?


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[romex jockey]

Get yerself a benfield or ugly's manual, a 100' of 3/4", and a 6 pack on your day off Dan



~RJ~

 

[LarryFine]

I never learned bender formula, I just bend by eye.

Don't 5' lengths cost much more per foot than 10'?

 

[OldSparks]

Get yerself a benfield or ugly's manual, a 100' of 3/4", and a 6 pack on your day off Dan



~RJ~

+1

 

[masterinbama]

Hello guys I'm fairly new at bending emt for offsets and such.

I use the following rules.

10 degree bends equals multiple of 6
22.5 degree bends equals multiple of 2.6
30 degree bends equals multiple of 2.


So this weekend I bought a klien bender bought some 5 foot sticks of 3/4 pipe and tried my hand at multiple offset bends.

Problem I was having was I would always end up with a level offset but 3/4 of an inch too much of a bend. Why does this happen am I putting too much of a bend in it or am I putting too little of a bend in it?

Everytime I do the math for for the distance between my marks. I mark the pipe bend it at the desired line on the bender(30degrees) flip it 180 degrees and bend at second mark...

How do I fix this and become consistent with exactly what I want instead of 3/4 inches higher than I want to be with my offset?


Sent from my Moto Z (2) using Tapatalk

Conduit bending is a learned skill. It takes time and experience to master.

I have 40 years in the trade and I still discover nuances. Below is some examples of bending done by 2 apprentices with 8 months in the trade.

My advantage is that they are willing to listen and learn..

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[electrofelon]

I don't know exactly where you are running amuck, but a few pointers:

1. Sight carefully down the pipe to compare the plane of the pipe to the plane of the line on the bender. You don't necessarily want the pipe to touch the line as you want it to be parallel with the line. The pipe is often above the line when it is parallel to the line.

2. Hold the pipe as close to the bender as you can. It will be harder to bend, but more accurate.

 

[480sparky]

One thing that's never mention, taught or talked about is.......... which direction you bend the pipe with the bender.

In other words, do you bend it always towards the same end......... or are you bending it first towards one end, and the second bend towards the other end? Some bends are the former, some bends are the latter.

 

[Knuckle Dragger]

Problem I was having was I would always end up with a level offset but 3/4 of an inch too much of a bend. Why does this happen am I putting too much of a bend in it or am I putting too little of a bend in it?

What they said.
Maybe you could do a trial run with a larger gage wire instead of conduit, just to get you bearings in order?
No better way to learn than by actually bending real conduit though.

 

[Danny89]

I don't know exactly where you are running amuck, but a few pointers:

1. Sight carefully down the pipe to compare the plane of the pipe to the plane of the line on the bender. You don't necessarily want the pipe to touch the line as you want it to be parallel with the line. The pipe is often above the line when it is parallel to the line.

2. Hold the pipe as close to the bender as you can. It will be harder to bend, but more accurate.

Thanks for the pointers

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[Danny89]

Conduit bending is a learned skill. It takes time and experience to master.

I have 40 years in the trade and I still discover nuances. Below is some examples of bending done by 2 apprentices with 8 months in the trade.

My advantage is that they are willing to listen and learn..

Sent from my LGL157BL using Tapatalk

That looks good I want to continue to learn always. Thanks for sharing your experience and wisdom

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[ritelec]

I'm in the bend by eye gang... although for the most part bending by the numbers work....
Suggest you work with it, you find that 3/4 " overage you have and play with future bends to make it work for your project.
Roll with it...

Or you can work for someone and practice on their time.....

Nothing against my union brothers, but when I was a member, I was foreman for 12 guys bending lots of pipe...smh, you should have seen the size of this VERY EXPENSIVE torqued, twisted, miss bent, pipe waste pile of conduit...
very sad,


The Bendfield book is a good read...

work on it, you'll get it

 

[masterinbama]

One of the asked where I got my numbers, I told him the trig table

Next day He came to work with drawings of different triangles.

I was impressed.

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[electrofelon]

How do you guys bend by eye? How the heck does that work? I dont see how one can do any real pipe work by eye. Im not attacking anyone's method, just genuinely curious. Isnt it a lot of trial and error? What if you have multiple parallel pipes, do you measure them then so they all come out the same? I even measure for offsets (I get made fun of a lot for that, but guess whose offsets are perfect, and whose like like crap.....).

 

[LarryFine]

How do I fix this and become consistent with exactly what I want instead of 3/4 inches higher than I want to be with my offset?

Have you tried to bend a 3/4"-less offset than you want?

 

[Fulthrotl]

How do you guys bend by eye? How the heck does that work? I dont see how one can do any real pipe work by eye. Im not attacking anyone's method, just genuinely curious. Isnt it a lot of trial and error? What if you have multiple parallel pipes, do you measure them then so they all come out the same? I even measure for offsets (I get made fun of a lot for that, but guess whose offsets are perfect, and whose like like crap.....).

being able to do it by the numbers, and by eye as well, is important.

if i'm bending emt 1" and less, i usually go by eye.

throw the pipe in the bender.
bend it till the handle is straight up.
find an expansion joint or straight line on the floor.
you want a 15" offset? put the pipe in the bender,
throw it flat on the floor, with the bottom of the shoe
on that expansion crack, and the bender handle
square with the crack. slide the pipe back and forth,
until you have 15" between the crack and the first edge of
the pipe.
pick it up, and bend until the handle is straight up again.

it'll come out within a quarter inch.

about 3 minutes.

if it's emt, bent it a smidge long, and cut to fit.

now, with GRC, you obviously have to think and do stuff
differently. it's gotta spin together, and it's gotta fit.

i had to run 2" grc up the catwalk on a floating lid tank
in a tank farm. the developed radius can be determined
with spherical trig and the oracle at delphi.

or, can take your folding rule, de regeur on rigid pipe
work, and stretch it out straight for 8', and measure the
deviation from straight, with it held in position. you
have to take your measurement square with the developed
radius, so eyeball it carefully.

then you trig it out and determine the radius, and use
a segment bender to generate the radius. i only had one
to do, but if i had a whole tank farm of them, i'd have sent
the pipe out to a fab shop, and had someone with a 3 roller
bender bend them all in an hour.

 

[LarryFine]

How do you guys bend by eye? How the heck does that work?

I didn't mean that I don't use a ruler, just that I haven't learned to use formulas. For example, if I need a saddle, I'll make the center bend first, then the two flanking bends,so the incoming and outgoing legs are in the same plane in both directions, horizontal and vertical.

For an offset, I know where one bend has to leave a surface or where a bend must be finished before hitting a surface. Sometimes, I'll sight along the pipe while holding the ruler along the bender handle and judge when I have the depth for the second bend right.

I do often make small adjustments by making a bend more or less sharp, or even moving a bend up or down the pipe by unbending it at one end of the bend, and then increasing it at the other end. The closer I get to start with, the less adjusting I need to do afterward.

A lot of time, what looks right is more important than what measures or calculates correctly. Also, it's sometimes faster to route two ends of a run toward each other and make the final cut where the two ends overlap, since a coupling will be necessary at that point anyway.

This is a job we did a couple of years ago; 100' basement-to-roof power and grounding for a rooftop cellular site. This is all rigid, which requires planning ahead to avoid having to use Ericksons, but sometimes, one is not avoidable. I used only a ruler to position these bends by cutting and threading:

 

[infinity]

Hello guys I'm fairly new at bending emt for offsets and such.

I use the following rules.

10 degree bends equals multiple of 6
22.5 degree bends equals multiple of 2.6
30 degree bends equals multiple of 2.


So this weekend I bought a klien bender bought some 5 foot sticks of 3/4 pipe and tried my hand at multiple offset bends.

Problem I was having was I would always end up with a level offset but 3/4 of an inch too much of a bend. Why does this happen am I putting too much of a bend in it or am I putting too little of a bend in it?

Everytime I do the math for for the distance between my marks. I mark the pipe bend it at the desired line on the bender(30degrees) flip it 180 degrees and bend at second mark...

How do I fix this and become consistent with exactly what I want instead of 3/4 inches higher than I want to be with my offset?

If your offsets end up being too large then you're angles are too large (you're over bending them). You might try a digital level or protractor until you get the feel for bending by eye. Eye bending is good for some stuff but you might as well learn how to do it using the formulas and accurate angles if you ever plan on doing precision bending. I use this one for everything from 3/4"-4":

 

[Strathead]

If your offsets end up being too large then you're angles are too large (you're over bending them). You might try a digital level or protractor until you get the feel for bending by eye. Eye bending is good for some stuff but you might as well learn how to do it using the formulas and accurate angles if you ever plan on doing precision bending. I use this one for everything from 3/4"-4":

View attachment 22865

finally a direct answer to the OP's question. For the OP there was a minor mention here about Trigonometry. Most bending though, is done with Pythagorean's theorem. If you want to get in to the the depth of where the multipliers come from,, look that up. But the sharper your angle, the taller your offset will be with the same distance between marks. Note that some benders bend 30 degrees when the handle is straight up and down, and some benders bend 45 degrees

OH, and is just dawned on me. It is possible you are measuring wrong. the measurement would be from the floor to the BOTTOM of the conduit, not the top of the conduit. Just in case.

 

[sameguy]

finally a direct answer to the OP's question. For the OP there was a minor mention here about Trigonometry. Most bending though, is done with Pythagorean's theorem. If you want to get in to the the depth of where the multipliers come from,, look that up. But the sharper your angle, the taller your offset will be with the same distance between marks. Note that some benders bend 30 degrees when the handle is straight up and down, and some benders bend 45 degrees

OH, and is just dawned on me. It is possible you are measuring wrong. the measurement would be from the floor to the BOTTOM of the conduit, not the top of the conduit. Just in case.

Hmm 3/4" pipe 3/4" too much. Coincidence? Make sure you measure from the same side as above.

 

[Danny89]

finally a direct answer to the OP's question. For the OP there was a minor mention here about Trigonometry. Most bending though, is done with Pythagorean's theorem. If you want to get in to the the depth of where the multipliers come from,, look that up. But the sharper your angle, the taller your offset will be with the same distance between marks. Note that some benders bend 30 degrees when the handle is straight up and down, and some benders bend 45 degrees

OH, and is just dawned on me. It is possible you are measuring wrong. the measurement would be from the floor to the BOTTOM of the conduit, not the top of the conduit. Just in case.

Thank you so freaking much this has been of great use to me thanks for the insight!


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