How the #$%^ do you figure out how to use one of these. I can bend a ninety but that about it. The distance bewteen bend got me screwed up. any tips on the reading on the side of this.
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Only way I figured it out was to practice on a bunch of scrap. Usually need to figure it out all over again as it does not seem to be like bicycle riding or swimming - if I dont do it for 6 months, seems I forget how (/:<)>
I've seen electricians with some sort of "cheat sheet" that apparently came with the bender -- tells you how to calculate where to start a bend to get the length right, etc.Part of it should be a decal on the bender. And, of course, there are usually degree markers on the bender head.
Depends on what you want to do. So you want a 10" offset? On one side of the bender are marks like 10º, 22º, 30º and 45º. On the other side there will be arcane numbers like __, 2.6, 2, and 1.4. If you're nathematically sharp, you will notice that there are related to the hypotenuse of the respective triangles.
Anyway, suppose you want a 10" offset. The easiest is the simple 30º offset. You multiply 10" by the magic number 2 and get 20". So you make two marks 20" apart. At the first mark, you make your first bend of 30º and at the second mark, you bend another 30º on the opposite direction and viola, you have 30º offset.
Actually, I prefer 22º offsets.
~Peter
http://www.porcupinepress.com/_bending/ConduitBending.htm
Edited 7/7/2005 12:22 am ET by PM22
Benfield makes a nice manual and video that will get you started in good order. They also make good benders. There is a little math to it. A bit of trigonometry and planning. One-off jobs you can do by eye.
Found the manual:
http://www.constructionbook.com/xq/ASP/ProductID.349/id.455/subid.506/qx/default2.htm?CMP=KNC-Google
A no-dog device, essentially a small level on a clamp is a good investment if you do much of it. At about $12 + S&H it saves a lot of trouble and makes complicated bends a lot easier but if you have a good eye you can do without. Mostly I do without but it is a grand tool and simple to use.
The device:
http://www.no-dog.com/nodog/
Manual to show you how it works:
http://www.no-dog.com/nodog/instr/
Conduit bending, particularly EMT by hand is a 'feel' thing. A standard box offset in half-inch or three-quarter is something I do by feel.
Learn and gain a feel for nineties, standard bends and offsets and everything else is just combinations. Practice. Do a few projects. Develop an eye. Kind of fun to do some hand bending in smaller sizes of EMT.
Rigid conduit in larger sizes is more setup and mechanical technique. Plan, mark, setup and use a hydraulic bender on a bending table to make the bends. And then there is the threading.
Cool site - thanks!
I just hadda buy one of these.........
http://www.no-dog.com/6inch/
there should be an arrow, a star, and a notch !
some benders won't have this, the Benfield type will !
The arrow is were your marks are set after deduct,
the star is where the mark for a back to back bend is placed ! when the second 90 is at the far end of the pipe.... turn the bender around and place your second mark on this star but make no deduction for this mark, eg. if the second 90 is 7' from the first ,make a mark at 7' and place this mark on the star and bend
the notch is the center of a 45 degree bend, place your mark there for 45's
no two benders bend the same , always slight variations !
if your 90s are consistently off a fraction , make adjustments to the deduct
lotsa ways to bend I hope this helps
Oh yeah, don't drop the bender on the hook
Most benders have the marks. But there are differences. Benfield/Klein units are set up to bend a thirty degree bend when the handle is vertical. Gardner Bender benders are set up so the handle is vertical when a forty-five degree bend is completed. The later seems more balanced, the 45 bend mid-stroke between engagement and 90, but engagement is done gripping near the head while bending a ninety is done gripping the end of the handle. Which means the GB makes you bend over more deeply to engage the head and set up the bend. Besides I bend a whole lot more thirty degree bends than 45s. Has to do with making pulling wires easier.The iron head benders are a little more durable than the aluminum ones. A point on commercial jobs where they are going to see a lot of use and abuse. A spritz of pam, wipe after letting set a while, on the shoe prevents rust and binding. My favorite is a combination 1/2" and 3/4" Klein head that saves room on the truck, is made of iron. The slightly larger radius onthe 1/2" shoe makes pulls easier, matching 1/2" and 3/4" look nice and the wide head lends stability and tends to sink less in soft ground. The combination head is quite unusual, I had to special order mine, and makes identification of who owns what simple. Of course it is such a handy unit that I have to keep an eye on it lest someone decide they like it more than I do. At lunch I take it with me. You can save money on handles by by buying the head separately and making your handle. Usually you can find discounted drops of 3/4" galvanized, black iron will work but galvanized is better, at the home center. I like a long handle, about 46" is about right for me. I can cut it to length with a hacksaw and file to remove and edges but often the guy in the home center can be talked into cutting it in the pony and deburring while it spins. You need one threaded end. A little blue Locktite keeps the head tight.Longer handles increase leverage and it gets the shoe closer to eye level when bending inverted. Something that happens more often than most people suspect. Go long when starting and if you find it too unwieldy shorten as desired.While your at the home center pick up a rubber foot, very like a crutch tip, As it gives the handle traction, slows the rate it sinks in soft ground and limits the amount of dirt the hollow of the handle is filled with. Dirt that tends to fall out on white wool rugs. Also a decent reason for the zinc on the handle. If the tip doesn't include one slip a fender washer into the tip before sliding the handle in. It prevents the pipe from cutting through the rubber. A dab of silicone caulk, don't forget to roughen the inside of the tip a bit, keeps it in place.The handy bending reference table gets a lot of use when you are learning. it can be photo-copied from the manual, cut down to size and mounted on the handle, nearer the head, by overlaying with clear packing tape.What ever you do don't let the rod busters get hold of your bender.If you do a lot of conduit work consider a set of hickeys. These are like regular benders without the shoe. Benders bend to a set radius in one shot. A hickey bends essentially any reasonable radius, which means you have to observe the minimums, but the bends are done a bit at a time. Bend, slide, bend, slide sequence. Hickeys have greater leverage so a shorter handle makes sense and makes them handy for tweaking conduits in attics, crawl spaces and trenches where bending in place is efficient. A lot of younger electricians have never used a hickey. Tell them to 'Give me a hickey' and they look at you funny.Read the manual a few times and have the tables handy for week or so. Mostly the rest is practice and getting a feel for it. Have fun.
O esteemed master,
I have to slightly disagree with you on the matter of use a piece of pipe as a handle. The advantage of the commercial handles is that the ends are swaged. This means that the ends are large enough to fit over the end of the conduit you are bending so you can tweak it [i.e. change a 91º bend into a bice graceful 90º].
To get the best of both worlds -- i.e. longer length than the commercial handles -- I alsp bought a ~12"~18" pipe nipple and coupling and inserted it between the regular handle and the bender head.
Have you heard of the Ericksen bender?
~Peter
I just give it a bash. Nothing fancy.In theory the handle can be used to completely straighten a section of EMT. In reality it seldom works well. Tweaking in smaller trade sized of EMT is often done by hand or with the head inverted. Even when the handle is the commercial version with the swaged end, the one you paid $20 for, it is rare to see anyone use it that way. Sometimes I have been known to whack the ninety on the floor to open it up a bit. Guy hands the ninety down and tells me to take five degrees out. OK ... Whack and hand it back. Funny how often it works.I had to look up the name to make sure we were talking about the same thing. Ericksen benders, long radius benders, have a place. They bend a lot of sizes with one bender, I don't remember this being a point, and the long radius bends are easier to get fish tapes and wires through. Sometimes people use a larger bender to get much the same effect. You can bend 1/2" EMT with a 3/4" bender or larger with care. Same principle.On the down side they are less precise instruments unless great care is used. The bends look more loopy and some consider them a bit sloppy. On tight jobs where there has to be a lot of boxes, to make the connections, and bends tightly follow surfaces they are less useful. Also the advantages of the easier pulls largely disappear on short runs where the conduit is minimally filled. Which amounts to the majority of short and medium runs.They are best for long runs where there is a lot of space to take advantage of that long sweeping bend and a real benefit to the easier pulls. The claims of fewer boxes and no need for pulling lube is questionable. Sure if the run was pretty easy to start with you might do without lube. And you might save a box or two on a large project. But in both cases there has to be precise calibration of the benefit versus regular short radius benders.Misestimation, finding that you should have added that box or used the lube in the middle of a pull is going to eat every bit of savings gained by using the Eriksen bender for the entire job. In other words don't count on fewer boxes or no lube. If the long radius bends saves you pull crew a minute a pull they could, on a larger job, still pay for themselves but the effect is subtle and incremental not revolutionary. Made still more marginal by the need to keep the regular benders around for box offsets, intricate conduit runs and following surfaces.I have seen these benders, or one similar as the idea has been around for a time, on a few sites. I don't own one and can't remember ever using one much. On the other hand for larger jobs automated, some are computerized, benders are handy. Dial in the degree bend, stuff in the conduit and line up the mark and hit the button. Bzzzz ... Buzzz. GTG. Some of these units cost $5000 or more. On the up side most will bend everything from 1/2" to 2". Floor model benders wil do much the same but they are manual and have less range. Then again they only run $700 or so. Both options are overkill for anything but a large commercial job.
Mr. Lorn,
Thanks for the lengthy reply. For those interested, here is the URL:
http://ericksenbender.net/
The reason most people don't use the end of the handle trick is because they've never heard of it -- that is, they don't read the brochures. On a recent job, the idea was to run 1" EMT under the joists and stub down to meet a piece of pipe coming up out of the wall below. I measured and it was 12". So I bent a 12" stub and test fit it. It was two inches too short. Silly me: I had forgotten to include the width of the tape case.
So I bent the 90º to 100º and then used the end of the handle to get it back to 90º. Now it was 13 1/2". So I bent it again to 95º and re-bent it to 90º and it turned out to be 13 7/8" which was good enough.
I agree that a sharp rap on the ground will relieve a couple of degrees of bend.
~Peter
Here is a good site with useful information about benders and hickies:
http://www.tpub.com/ceb/68.htm
Good link, thanks for sharing!