segment bending ?

[mryan]

Does anybody know of a calculator to help with segment bends ?

 

[cadpoint]

Bending for Tommorrow or Monday, please describe the application!

 

[cpal]

I like this one http://www.coxco.net/Conduit_pipe_Bending_Book_p/b0010.htm

 

[Rockyd]

?

Radius x 1.57 for total length of bend.

Center lines should be = to or greater than the diameter of the pipe.

Grab an Ugly's book - it's a good guide if you don't bend segments a lot

 

[mivey]

http://www.porcupinepress.com/_bending/segmentbends.htm

 

[cadpoint]

Face it

Where all just a bunch of high tech - rednecks...

 

[480sparky]

Does the ElectriCalc have it?

 

[cadpoint]

From a Search Engine Here

And long hand; 1.5" to 4" Here

FYI the #4 response was the number one answer on your statement of "segment bending" if used as a quary to a search engine...

 

[mryan]

segment bends

segment bends

http://www.porcupinepress.com/_bending/segmentbends.htm

thanks for the lead this could come in handy,anything for 360 degrees ? big tanks

 

[ohmhead]

Well the best book is in cpal post i use it at work segment bending is a art it takes lots of practice and years to master it but theres nothing more important then actual hands on bending in the field you can calculate all day long but bending pipe is were its at .

Each electrician has there own methods but its degrees to inches to shots made thats the key think 90 degs think how many shots you want to make each shot will bring you closer to you bent 90 deg pipe .

Before they had books to bend pipe we did it by actually bending and made our own books for different electric or i should say the old hand pump benders most important use center line use a fine pencil not a magic marker its more accurate and get a angle finder with two levels for your bending .

Good luck practice makes perfect but read that book cover to cover its the best Big tanks are fun you bend small conduits on the tank itself mostly we use aluminum on industrial stuff and we bend it on the tank or if its rigid we make a emt sample as a template .

 

[mivey]

A more precise formula

A more precise formula

thanks for the lead this could come in handy,anything for 360 degrees ? big tanks

The formulas in the books and in the web calculator I linked are approximations and do not account for chord length but assumes the bend is circular.

Using the more exact method with chords, for any angle the distance between bends is given by: 2 * inner_radius * tan[angle/(2*#bends)].

For example, to get a circle with an inner radius of 10" and 8 bends:
2*10*tan[360?/(2*8)] = 20*tan(22.5?) = 20*0.4142136 = 8.2843" between bends. The developed length = 8 * 8.2843 = 66.2742".

Another example: to get a 90? bend with an inner radius of 10" and 3 bends: 2*10*tan[90?/(2*3)] = 20*tan(15?) = 20*0.2679492 = 5.3590" between bends. The developed length = 3 * 5.3590 = 16.0770". Compare to the book approximation using a segment length of 5.23" and developed length of 15.7".

As the number of bends increases, the approximate method approaches the chord method. This is because we are getting closer to a circular shape:

For example, to get a 90? bend with an inner radius of 10" and 30 bends:
2*10*tan[90?/(2*30)] = 20*tan(1.5?) = 20*0.02618592 = 0.5237" between bends. The developed length = 30 * 0.5237 = 15.7116". Compare to the book approximation using a segment length of 0.52" and developed length of 15.7".

Keep in mind that even the more precise calc using chord lengths will not exactly match the field results because the field bends not sharp angles between chords but mini-arcs. The chord method should give better results but you need a calculator with a tan function.

 

[mivey]

The formulas in the books and in the web calculator I linked are approximations and do not account for chord length but assumes the bend is circular.

Using the more exact method with chords, for any angle the distance between bends is given by: 2 * inner_radius * tan[angle/(2*#bends)].

For example, to get a circle with an inner radius of 10" and 8 bends:
2*10*tan[360?/(2*8)] = 20*tan(22.5?) = 20*0.4142136 = 8.2843" between bends. The developed length = 8 * 8.2843 = 66.2742".

Another example: to get a 90? bend with an inner radius of 10" and 3 bends: 2*10*tan[90?/(2*3)] = 20*tan(15?) = 20*0.2679492 = 5.3590" between bends. The developed length = 3 * 5.3590 = 16.0770". Compare to the book approximation using a segment length of 5.23" and developed length of 15.7".

As the number of bends increases, the approximate method approaches the chord method. This is because we are getting closer to a circular shape:

For example, to get a 90? bend with an inner radius of 10" and 30 bends:
2*10*tan[90?/(2*30)] = 20*tan(1.5?) = 20*0.02618592 = 0.5237" between bends. The developed length = 30 * 0.5237 = 15.7116". Compare to the book approximation using a segment length of 0.52" and developed length of 15.7".

Keep in mind that even the more precise calc using chord lengths will not exactly match the field results because the field bends not sharp angles between chords but mini-arcs. The chord method should give better results but you need a calculator with a tan function.

If for some reason you want to run the pipe on the inside of a circle (the circle touches the outside of the bends instead of the middle of the chords on the inside of the turn), you need a different formula. In that case, the distance between bends is given by: 2 * (circle_radius - pipe diameter)* sin[angle/(2*#bends)].