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-   -   Calculating 90 degree conduit bend (http://www.diychatroom.com/f18/calculating-90-degree-conduit-bend-94265/)

Richo 02-01-2011 08:22 PM

Calculating 90 degree conduit bend
 
Hey guys,

I have this Gardner Bender conduit bender for 1/2 EMT. Having a hell of a time calculating where to line up the bender to get an accurate measurement for a 90 degree bend.

I've watched a few clips on YouTube on how to calculate the bend but they are referencing off some kind of "star point" on the bender and mine doesn't have one of those.

http://www.fortunetalent.com/images/bender.jpg

It reads DEDUCT 5" FOR 90 STUB AT ARROW - Which arrow? There are 6 of them. :confused1:

Any help would be appreciated. Thanks.

nap 02-01-2011 08:25 PM

the arrow clear to the right. It is the only arrow like it. It does not have any number and associated with it.

it's the 7th arrow.

Ideal (brand) benders use a star

Richo 02-01-2011 08:33 PM

Ahhh there it is, doesn't really stand out and didn't see it until I knew to look for it.

Thanks!

frenchelectrican 02-01-2011 10:34 PM

The arrow point without any number is the 0 that is your starting point.

And make sure you are aware you have to deduct 5 inches if you going to make a inside bend (90) any other you may have a conversion chart on the handle itself { some will have some don't }

If you need any tips or more info just ask us we will tell you few tips on them.

Oh yeah take a peice of scrap conduit and pratice on that.

Merci.
Marc

Richo 02-01-2011 10:40 PM

So deduct 5" for an inside bend? What about for an outside bend? Deduct 5.5" or 4.5"?

The bender didn't come with a handle. I just use a 4' black pipe.

Technically, couldn't you measure exactly 5" from the arrow and mark that as the "star point"?

frenchelectrican 02-01-2011 10:47 PM

Quote:

Originally Posted by Richo (Post 582902)
So deduct 5" for an inside bend? What about for an outside bend? Deduct 5.5" or 4.5"?

The bender didn't come with a handle. I just use a 4' black pipe.

Technically, couldn't you measure exactly 5" from the arrow and mark that as the "star point"?

For the inside bend Oui., that is correct.

For the outiside bend that will varies a bit depending on how you run it if you have outside corner most case useally the LB or corner ellbow conduiet will do the trick.

I don't use the black pipe with me I end up use the stainless steel pipe due I have two benders on one pipe one for half inch EMT while other one for 3/4 inch EMT or half inch ridge conduit { heveywall steel conduit }

for your last comment Oui you can do that as well each one have diffrent methold to work the best. { I do run in inches and Millmeter scales so I go both ways }

And also let me give you a head up when you bend them just go a little more than you plan to go X number of degress you want the reason why to comperised the springback.

And do this on smooth surface so that way you don't get any kink in your conduit bender.

Merci.
Marc

nap 02-01-2011 10:48 PM

inside/outside? Not sure what you mean.

Using that 5" deduct method, you can bend a 90 bend with the ends sticking forward to a predetermined length. That's it.

If you want that stub end (generally what it's called) that is 20" long, you deduct 5" from that measurement and make a mark. You put that mark at the arrow and bend a 90 bend. That will result in that stub end, measured from the end of the conduit to the back of the bend to be 20".

There are a variety of methods employed to make a bend how you want it to be. Did you get a manual with the bender?


and in addition to marc's "how to"; use a lot of pressure with your foot. With 1/2" conduit, I actually do most of the work with my foot. As the pipe gets bigger, you have to yank on the handle harder and harder but you still need to keep pressure on the bender with your foot. If you don't, the conduit will not be forced into the shoe and you end up with kinked conduit and nobody liked kinked conduit.

Richo 02-01-2011 11:01 PM

I bought the bender a long time ago. I know a few instructions came with it but have no idea where they are. Went to GB's website and they don't have any documentation for that particular bender model.

Looks like a stub end is what I'm looking for.

I always used the bend first, then cut to size method but it's time to try to do it the right way :)

Thanks for the tips!


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