Calculations for Conduit Bending

[2Broke2Sleep]

Hmmm.

I can't believe what I'm reading. This guy is saying the bend-to-bend distance multiplier changes because we are making a saddle bend and/or using different benchmarks... and then for push through bending we add the conduit OD. :roll::happysad:

I have to wonder if the author ever took geometry or trigonometry...

My bending techniques are based on traditional concepts—developed length, shrink, gain, tangent points, etc.

I have had to read between the lines here and there throughout the book. The change in benchmarks he is referring to I understood as ditching the arrow and finding your center of bend on the shoe you are using. I never dug into why the distance multiplier changed? And then again for a push-thru?

 

[Smart $]

I have had to read between the lines here and there throughout the book. The change in benchmarks he is referring to I understood as ditching the arrow and finding your center of bend on the shoe you are using. I never dug into why the distance multiplier changed? And then again for a push-thru?

Changing the benchmark (more commonly known as bend mark when discussing this topic) only changes the position of the conduit in the shoe. It is still the same shoe and bends the conduit the same way as if you determined where to place the mark to align with the arrow.

 

[2Broke2Sleep]

Changing the benchmark (more commonly known as bend mark when discussing this topic) only changes the position of the conduit in the shoe. It is still the same shoe and bends the conduit the same way as if you determined where to place the mark to align with the arrow.

Did you make any sense of the O.D. being added for the pushthru? Can't bend my head around it...

 

[Smart $]

Did you make any sense of the O.D. being added for the pushthru? Can't bend my head around it...

None whatsoever. Geometrically speaking, the OD does not enter the picture for anything other than determining the bending radius of the shoe.

 

[2Broke2Sleep]

I'll just have to settle with what I know now. If I ever do exposed RMC runs again I will have to revisit all of this though. I ran some calcs with the different methods and they are all pretty similar in outcome. I think the distance to bends has some room for error but the center mark and shrink are the most important, which is easier to figure.

 

[Smart $]

I'll just have to settle with what I know now. If I ever do exposed RMC runs again I will have to revisit all of this though. I ran some calcs with the different methods and they are all pretty similar in outcome. I think the distance to bends has some room for error but the center mark and shrink are the most important, which is easier to figure.

Being an apprentice there is a good chance you will run RMC again. As you have found, you can fudge the numbers and still be in the ballpark.

FWIW, the formulas apply to any conduit you have to bend... including EMT.