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I Forge Iron

bending thick stock for gate


andreas

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Can it be bent cold ? Yes.  Would I bent it cold? Depends on a lot of things starting with the material you are using. I think there is a lot of structural steel which is fairly easy to bend. On the other hand I got some pieces that looked like A36 but were a lot stiffer,  Also depends on how closely the bends are required to follow an exact design,

Were I doing that gate I would drive 60 miles to a friends shop, with a supply of refreshments, and use his set up table. Then I would lay out the inflection points on the table for each piece and use his big oxy/propane torch to encourage the bends as needed. To much heat differential along a piece, in my experience, can cause a bend intended to be organic to look anything but.

I saw a demonstration of a set up temporary propane forge that heated 6 foot round to orange .  the Smith and two helpers would grab a bar and bend it on a table around marks welded to the table.

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I was hoping someone would come up with some "I did that easily with.........." kind of story. Wishful thinking. I've never done something quite like this. I do have a small hydraulic ring roller I can try. 

"I did that easily" for a project I'm working on making tighter radius than the OP pics using the bender I made. 

wheel is set with a bearing and is turned buy a {believe it or don't} 3' cheater bar that has pins that fit the 1/2" holes near the perimeter of the wheel. It was cobbled together from scrap I had laying about. the oblong piece doesn't do anything special except raise the stop pin to proper height. I need to drill more 1/2" holes for more easier positioning but it got me through the bends some of which had less than a 6" radius

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pipe-bender.jpg

source, the practical dilettante

a hoop bender is an alternative, it is important to support the rod as it is bent (like dodge is doing) or do it vertically so you can tweak as you go or else the curves will wander out of the nice flat plane you want, the gate will have bulges out the front and back that looks very unprofessional and sad.

PS this is for a 12 foot hoop, it needs to be scaled down to some 4-12 inch versions

Edited by yahoo2
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I made a pool fence similar to this and we made up a "random bend generator", cut all the stock to length, spread (dropped bundles wherever) it out in front of the workshop, and then drove the forklift backwards and forwards over it several times.

 

Andrew

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You can do it that way. It's often referred to a "bump" bending. The closer you make your bends, the smaller they need to be, and the less likely they will get noticed.

 

You can also do the same thing cold with a hammer and a die that supports the stock in two places. I used that method to cold bend the 1/2" x 1" stock for the arches on my forge legs. I thought I had picts of the bottom die I used, but can't find them. The pict isn't the greatest, but it shows them cold bending heavy stock at ABANA 2014 last year using a similar bottom die and a striker.

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Edited by DSW
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Like your bender Dodge! So you're just making a series of smaller bends to get the radius you want I assume?

Yes, but only because I didn't have a larger center "die" to bend around. I found, with the bender as is I could bend the 5/8 in a radius as small as the 2" die in the pic as long as I had enough length to catch with the stop end and bender bar (not shown) end.  I just didn't need that small of radius. Once you overcome the initial....."force that keeps it straight"  (I know there must be a physics term here ;) ) it continues to bend easier. And changing the distance of the outer "pin" that pushes against the 5/8 also changes leverage. i.e. closer to the center yields more leverage. My plan is to drill and tap more holes to make the whole thing more versatile. 

Scott

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Went with the KISS principle. Kept it simple. Put my stock up against the block and bend around the form. Do a series of small bends for the more gradual curves. Working well so far.

 

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Edited by andreas
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congrats Andreas, you have got the idea! Nice bit of lateral thinking there. Good chance the sheave will not handle the pressure and crack a piece out at some stage but hey, if it is not a keeper then its not a problem.

Rod bender 1.0 equals two thumbs up!

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20150812_163517.thumb.jpg.01ac81a8077e50Finished except for final welding and paint, and hinges, and install etc.  The 5/8 bent fairly easily, only needed a cheater bar on the tighter bends near the ends. Jig did the job. Another question though.... the frame is cupping up towards the welds, will welding opposite sides reduce this? Sorry about the sideways pic, haven't figured that out yet. The pulley was actually going to the metal recycle, but I thought it might come in handy for just such an occasion, which it did.

Edited by andreas
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If you have access to a Hossfeld #2 bender, you can do most anything w/ 5/8 bar cold.  A local machine shop came to me 3 mos ago needing 4 bars of 5/8 4140  bent in a particular shape and tolerances were pretty tight.  I practiced on some 5/8 oilfield sucker rod (drill rod) and that bent easily COLD.  So did the 4140 but just a touch harder to bend.  The machine shop specified the bends to be all COLD.  One bend was 180 degrees w/ a 2 3/4" inside, the other was a 90 degree sharp bend.  Use some WD40 or some such oil and it helps the bending a lot.

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