Parallel Bends

[Power Tech]

It should take no longer to do it right if the person is a good craftsman. Or you can do the "McPherson bend", bend it in the middle and cut both ends off.

 

[iwire]

It should take no longer to do it right if the person is a good craftsman.

What is right?

 

[peter d]

Or you can do the "McPherson bend", bend it in the middle and cut both ends off.

I've always hated that technique. I know that it can save time, but it doesn't take much to learn a few measurement techniques. Once you know how to bend pipe with the correct measurements you will be beating the "cut to fit" guys hands down.

 

[infinity]

Bending and cutting the end is not an option when installing large rigid conduits. Trying to cut and thread a short end is much more difficult than bending it properly in the first place, if not impossible.

 

[Rockyd]

Where's Celtic? The more one understands π (Pi) the better bender they can become. If he's busy, a good grip on the tables, and knowing radians will help.

First tool in the box is a copy of the "Greenlee Conduit Bending Handbook".

A protractor (Sears craftsman is good enough) Maybe two protractors if the bender table isn't set up level, and your bending in an ugly spot.

A piece of surgical tubing with various sets or markings.

Now get out there and cut-n-thread some pipe, so we can bend it up, and make someone proud that we can do it with a minimum of tooling!

Edit- It takes at least 12.5 inches of pipe to thread a piece of 4" GRC with a mule. 24" for most Ridgid 300 style threaders, so it is important to be able to cut, thread, then bend

 

[nevadadave]

There isn't a way to do concentric bending w/o all the math.
Greenlee does have some good manuals that will fit in your pocket and have a lot of the math done for you.
A while back, I was cursed w/ getting the last bender in the shop which was a segment bender. I picked it up pretty fast, but would not call it easy.

It has been a long time since I was in the field but I recall being able to produce decent concentric bends quickly when needed. Let me see if I can explain what I remember and I am sure we can fill in the gaps.

To knock out a decent set of concentric bends in the field, (i.e. GF standing over you yelling about 7million feet per day is not enough) we used a method of shot bending just like every body knows. The main difference being the layout of the bends.

With a laser level (or plumb bob) you can easily and quickly transfer your rack dimensions to the floor where it is easier to work. This makes it easy to use a framing square to determine the centerline and bend radi. I find the center of the circle and measure out with a tape.

The bends are produced by making 15 evenly spaced bends of 6? each, but we dont measure these I dont even care to know the distance between the bends because the next step takes care of that for me.

Using a length of 1" wide elastic strip with 15 evenly spaced marks every four inches or so is the secret to speedy layout. Take the overall length of bend mark first and last then stretch the tape between and viola, conduit is ready to be bent. equal bends every time!

This method eliminates much of the math, and for many, much of the errors in preforming concentric bends. Hope that helps. If I missed something it is because it has been a few years since I was in the field as nowadays I get to play estimator.

The estimator's version of concentric bends = "counts just like every other 90" hehehe