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Benders and Bending Which bender is best? How do you use a bender? How do you calculate bends? Everything Bender related...


Benders and Bending Which bender is best? How do you use a bender? How do you calculate bends? Everything Bender related...

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  #1  
Old 12-16-2009, 12:58 AM
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Haku Haku is offline
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A thought about a hydro upgrade for my JD2 using power steering parts..

I bought a JD2 model 3 bender used a month or so ago, and have wanted to make it hydraulic ever since. I like the copper fab/harbor freight air ram thing, but its loud and I don't have a suitable compressor for it either.

So here is my thought. What about going to the junkyard and finding a power steering setup, and using that to provide the pressure for a hydraulic ram. I have a 12" travel ram already that I got off someone for $20 bucks. I imagine a cheap variable speed grinder could be rigged up to provide the power to the pump, and then just drill and tap a steering box for the control side of things. It would essentially be setup the same as hydro steering setup. Seems like it would be quieter, smoother, and would also have a return mechanism.

Seems like a Saginaw style pump off GM trucks and others would work great since it already has a resevoir. I haven't seen anyone do this, but it seems like a good cheap way to go. What do ya'll think? Sorry if its been brought up already too.

JH
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  #2  
Old 12-16-2009, 01:25 AM
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interesting...
I'd be curious as well to see how it would work. some cheapo electric motor with a pulley hooked to it.
I'd personally rather buy a real lever control valve rather than a box, but I like your pump idea. As far as reservoir, its not gonna be big enough, but really, its easy to make a larger container be your reservoir.
best thing to look at, are the pump specs. 1+gpm flow and probably 3k PSI and I would think you are golden.
Cheers, and keep this idea goin if it works.
Homebrew fabbers would fall in love with it if it does!
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Old 12-16-2009, 01:34 AM
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Good call on the lever controls. I have some researching to do.

JH
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Old 12-16-2009, 01:36 AM
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just looked up some pump specs... most have more than enough flow rate, but stock are only 1400PSI ish... not near enough IMHO.
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  #5  
Old 12-16-2009, 01:52 AM
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Could be. My thought was that its enough force to easily provide power for both a power steering box and hydraulic ram in an Hydro assist setup, and the forces there are pretty intense sometimes. Still, might not be enough to bend tubing. For me, I need it to handle 1.75" .120 wall tubing for now.

JH
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  #6  
Old 12-16-2009, 02:21 AM
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I would love to see what you come up with as well. Post pics if you do it.
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  #7  
Old 12-16-2009, 07:13 AM
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I worked for fabricator who did excactly that ,stock ps pump from early chevy truck,stock res. is plenty of volume,he used a basic 110 motor to power the pump with the stock pulley.Its so simple its rediculous,and its worked for at least the ten years i've known him.We used a valve with a remote handheld awitch too.

Only difference is we used a hossfeld bender,which i think has a longer arm than the more common jd style benders,i think,so the ram doesnt need as much power.

Give it a shot.

One of these days i'll get some pics of the setup.

Now, what i would like to see is someone try the box as well,mounted like the Baliegh style benders.I mentioned this before on here but noone commented.
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Old 12-16-2009, 08:19 AM
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There is a older thread on Pirate 4x4 that has about every configuration of hydro setup you can imagine. Good info in there to be sure.

http://www.pirate4x4.com/forum/showthread.php?t=185940

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  #9  
Old 12-16-2009, 10:00 AM
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with the auto pump, from what I understand.. you would use a cylinder with a larger bore? Say a 4" bore X 24" stroke? wouldn't that make up for being a lower pressure setup?
damn.. I used to have hydro calculaters somewheres..
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  #10  
Old 12-16-2009, 10:15 AM
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"With 1000 psi pump pressure exerted against a 12 square inch piston area (approximately 4" diameter), a force of 12,000 pounds is developed by the cylinder. The speed at which the piston will move is dependant upon the flow rate (gpm) from the pump and the cylinder area. Hence, if pump delivery is 1 gallon per minute (231 cu. in./min.) the cylinder piston will move at a rate of 20 in./min (231 cu.in. / 12 cu.in./min.)"

So with that being said, do the Steering box mod here
http://westtexasoffroad.homestead.co...rsteering.html
and you should be golden!
you WILL need a larger reservoir tho. If you use a remote reservoir pump, then no problems there.
This valve:
http://www.northerntool.com/webapp/w...70_37216_37216
This cylinder:
http://www.northerntool.com/webapp/w...4000_200394000

Last edited by idahoaj1; 12-16-2009 at 10:21 AM.
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  #11  
Old 12-16-2009, 10:26 AM
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Heres a good link to help you out,
http://www.northernhydraulics.net/hydraulics101.html
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  #12  
Old 12-16-2009, 01:57 PM
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That Hydraulic Cylinder you linked to looks very similar to what I have. The stroke is longer on that one, so it will have to short burst of push with mine (mine is more like 12-18"). Not sure on the cylinder size, but I'll go check.

Thanks a bunch for the input so far. Its gonna take a bit to get all the parts, and then fab a system to mount it, but I'll keep ya'll posted for sure. Right now it just has the standard 4" sqaure tube style manual mount, so I'll have to make a "got trikes" style cart for it. The big question is, does this have benefits over the Harbor Freight Air ram style setup (i.e. stronger, faster). I know it will be quieter and not require a compressor, but looks like its gonna be a similar price or maybe even a bit more. I need to get a compressor anyways, just was hoping to not have to right away.

Another off the wall thing that a friend and I were talking about last night, was that for a portable setup, one could make a fold down shelf that you could stand on to do it manually. The main reason people have to lag it to the floor is that if you didn't, you'd just move the bender and not do any bending. We propositioned that if you made it with a big piece of plywood, and mounted the bender securely to it, that you could put the bender wherever you want and still used it manually. I'm sure we aren't being particlularly novel in that idea, but it sure would be easier for me to do it that way then have to lag into the concrete of my landlords garage. Its the main reason I wanted to go Hydro, besides being a lazy ass.

JH
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  #13  
Old 12-16-2009, 02:06 PM
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Quote:
Originally Posted by Haku View Post
The big question is, does this have benefits over the Harbor Freight Air ram style setup (i.e. stronger, faster). I know it will be quieter and not require a compressor, but looks like its gonna be a similar price or maybe even a bit more. I need to get a compressor anyways, just was hoping to not have to right away.

Its the main reason I wanted to go Hydro, besides being a lazy ass.

JH

you answered all your own questions!
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Old 12-16-2009, 02:06 PM
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this is a great idea but most bender hydro upgrades use a 14" cylinder so make sure you don't have a cylinder with more travel than your bender can use

Dave
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  #15  
Old 12-16-2009, 02:10 PM
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Quote:
Originally Posted by idahoaj1 View Post

you answered all your own questions!
Ummm......did I? I wasn't sure if this is indeed stronger and faster, though I do know its quieter. This is the first time I have really done anything with Hydraulics at all, so its a strange new world.

Oh, and thanks for the heads up about making sure the stroke is limited to 14".

JH
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  #16  
Old 12-16-2009, 05:35 PM
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There's no reason it can't work with the right motor driving it at the right speed and the right combination of cylinder mechanical leverage & piston diameter.

If you are doing a typical 2" capacity bender like a JD2 Model 3 or Pro Tools 105, shoot for something in the neighborhood of 5,000 ft-lb or 60,000 in-lb maximum bending torque (FWIW, the 1.75x0.120 chromoly I've bent in my bender took just under 4,000ft-lb IIRC).

Next determine a suitable position & orientation for the cylinder, I would recommend setting it up to operate perpendicular to the bender arms to maximize torque for a given cylinder size and prevent unecessary loading of the arms/pins that occurs if you put the cylinder more inline with the arms.

Now calculate the force the cylinder needs to generate. To do this first measure the PERPENDICULAR distance from the intended cylinder location to the center pin of the bender. Divide the required torque (60,000 in-lb) by this distance (make sure the units match, inches for distance and inch-lb for torque). If you have a JD2 Model 3 or PT 105, I'd estimate the distace from the center pin of the bender to where a cylinder is often mounted at 16inches, so you would need 60,000/16=3,750lb from your hydraulic cylinder.

Next calculate the required cylinder diameter to generate this force based on your operating pressure. Let's assume your PS pump can deliver 1,200psi reliably. Divide the force by the pressure to determine the piston area for the cylinder. In this example, 3,750/1,200=3.125in^2. The area of a pison is A=3.14*dia^2/4, so the diameter is dia=square root of(4*A/3.14). In this example, the required cylinder diameter would be roughly 2". Some people might think this seems small, but remember - this assumes the cylinder is mounted PERPINDICULARLY to the bende arms. This is a much more favorable orientation than when the cylinder is driving parallel with little spacing from the bender arms like my bender and many of the custom hydraulic conversions I've seen.

That takes care of cylinder sizing, now you need to determine your flow rate and from that the required horsepower to drive the PS pump, but that will have to wait for another time because I have to go right now. *EDIT* Maybe this should be modified into a tutorial.
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  #17  
Old 12-16-2009, 07:57 PM
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Thats some good info right there!

I think your right on with the ps pump pressure,i remember my neighbor mentioning something in that range.

Also, i think the ram is rather small dia. like you mentioned,definitely under 3".

I'm looking forward to seeing the outcome of this.
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  #18  
Old 12-16-2009, 08:39 PM
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you can use 24" or even 36" stroke rams if you want. The key is mounting the ram and measuring the amount of travel it will really take. alot of the guys on the pirate thread used 24" stroke rams perfectly. Just because the mfg supplied ram has 14" stroke doesn't mean thats the max.
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  #19  
Old 12-16-2009, 08:46 PM
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Here is the label of the ram I have......



Can't find any information on the specifics of it, but from looking at the website for the company, they make 2" and 4" versions. The label doesn't say anything about the cylinder size, but it does say that it has a 1.125 rod. I'd be psyched if this worked size wise, since I got it for $20 bucks. Evidently it came off a 5th wheel car trailer, and was used to raise and lower the feet on the front of the trailer for when its off the truck/tractor.

I noticed there are two pumps, one thats like 1200psi and another thats 1400 psi. I'll have to go see if I can find of the higher rating ones at the Junkyard in the next week or so. I'm thinking that just getting an average everyday bench grinder and mounting a pulley to it should be enough. Harbor Freight has some 3/4hp 3450rpm ones that seem sufficient, or I'm sure some pawn shops or Craigslist would bear fruit too. The goal is have this setup be cheaper then just buying a electric Hydraulic motor/pump/resevoir combo, which can be had for $250 if you get a 12v one. Haven't found many 120v ones, but the few that I have seen are very spendy. Harbor Freight does have a 220v version of this for $300ish, but that doesn't help me since I don't currently have a source for 220v. So yeah, thats where I am at right now.

JH
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Old 12-16-2009, 08:58 PM
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some of the other ppl that do hydro setups have said that even a 2" rod has problems with bending... somethin to watch for and be aware of.
what pump is the higher rated one?
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