Advice in cold bending rod

Anyone got some advice when it comes to cold bending rod ? I've been having problems making trap frames. Basically I'll make my cages wire body then I'll measure the inside and try and make my frames. So say my cage needs a frame thats 7"x10". Well just marking the rod @7" then 17 ect then trying to being that just never seems to work right. Seems the best way to do it just keep bending till I get something right then kinda go off of that but there still seems to be alot of extra"art" to this. Not it mention it took me like half an hour to get everything just right .
Is there some kinda calculation a guy could do to get a perfect ( or just a really nice) bend ? Or anyone got a video that really getting into making precise cold bends ? Would really like to be able to sit down lay out what I want then be able to bend it right the first go.




Thanks !

Practice practice practice.


Put it in the vice and bend it. If it doesn't line up with your mark, adjust your mark on the next one, till you get it right.


Build your self a bending machine. No doubt in my mind that you can do that



Charlie

if you measure mark and bend then measure where you actually came to

so say you measure 7 mark and bend over the vice what does it actually come to 7 1/4 what ever it comes to I would think you need to take off the 7

so say it is 7 1/4 you would take the 1/4 off and mark at 6 3/4 so that bent it is 7

your making a radius so figuring in for the radius is necessary when I was bending a lot of conduit I knew what my measurement was , I don't recall all these years later

a couple test bends should tell you

If you have a heavy welding table and your cages are the same size every time the simple answer is build a jig on your table . It might take a time or two to get it right but once you’ve got it your golden for the duration.

I would think if your cages are 7”x10” it would be a matter of building the jig a quarter inch smaller ( depending on rod size ) say 6” 3/4 x 9” 3/4 and 6”3/4 x 9”3/4 , weld 4 pieces of angle on the welding table and start bending. That’s assuming your using 3/16” rod .

You're going at it from the wrong side. Make the frame FIRST, then make the body wire fit it. Don't forget you can get sharper corners with hardware cloth body material, than with the frame material.

Well that's the thing I'm probably going to be making cages that are all over the place as far as measurements lol. Really looking at making jigs however.think I'll go buy th school and see if my old welding teacher has some scrap plate I can get . Now what you said about building it smaller is what got me. You said build it 1/4" smaller if I was using 3/16. Why exactly? Wouldn't I bud then 3/16th smaller ? And since I'm building thea out of 1/4 would I build them 1/2 smaller ??

Wolfdog91, yes there are formulas for developing length adjustments for the bend radius. Unfortunately my engineering resources are all packed up in storage.

For each bend the allowance will always be shorter based on: the elongation material properties of the rod you are bending, size of the bend radius, rod diameter, and the amount that the neutral axis moves from the theoretical bend axis due to compression around the inner material fibers and tension ( stretch) in the outer material fibers (think of the rod as being made up of laminated layers of material.)

Wolfie, why do you have to do it cold? Couldn't you use a small torch (map gas would be quite fast) to heat the small spot you want to bend, then quickly get it in a good vise and hammer it over before all the "red" is out of it.

Wolfie do they have to be bent? Along the lines of above questions, why not just cut everything and build a little fixture plate to tack it all together?

First question, What are you bending the rod with??

I’ve done this on my swimthrough cages and it works quite well!

I have a pair of bolt cutter that have a bender built in that work awesome. I don't know if anyone makes them anymore. I have a huge rebar cutter too that has a bender on it but it's no good for real sharp bends or smaller stock like used in cage traps.

Bolt cutters are like these.... https://www.ebay.com/itm/363870976527?hash=item54b8667a0f:g:T7QAAOSwg2ViplEv

Well I've always hav just cut and welded but I kinda wanna get good and bending. Seems every cage maker worth their salt does it so it's something I'd really like to get a good grasp on. Also since I'm running a stick it's a literal nice to just make one weld instead of four

A vice and a hammer. I tried using I pice of tubing slipped of my rod like a cheater bar but my beinds never looked quite right

Well I just doing it cold right now because I don't have an oxy torch yet. I haven't tried map yet for this, how fast is it compared to oxy ?

But even then I will kinda stuck on properly laying stuff out for a bend

Work great

Congratulations. It sounds like you have discovered "bending gain".

While I cannot disclose what cost me hundreds of dollars in class courses and experience I will say there is a factor, and it is dependent on radius.

If you figure it out feel free to let some of the other folks on here in on your discovery.

Hint: Perhaps the factor .44 could come into play

One of these will save you a lot of head aches.
https://www.minntrapprod.com/Bob-Custers-B2B-Trap-Bender/productinfo/B2B-01/

Actually I've had three of these now , learned don the first two they really don't like 1/4" rod lol

A hint ! Awsome that's all I need now off to YouTube I go !

As others described I build a jig on a piece of plate. Simply put I lay out the part on the plate in chalk, weld round stock pegs in the corners to bend around, angle iron keepers on the outside to prevent rebound when bending the next corner. Make a tool to bring the stock you are bending around the rod tight. Basically, a bar with a hole to fit over the round stock pegs and concave surface under the bar to push the stock you are bending tightly around the peg. You need something to hold onto the end when you start so that it doesn't pull away from the starting point when you make your first bend. make your jig close to the edge of the plate and you can use a good vice-grip.
Also, drill a hole through your plate in the middle so you can bolt it directly to a heavy welding table. Preferable to have your table attached to the floor or it will move when bending.

I have a bending tool , one thing to remember is the size rod you're bending .
I bend 1/4 inch rod , and three bends adds 1 1/2 inch to the length . So for a 12x12 trap , you start out with a length of 1/4 rod at 46 1/2 inches .
You have to have a good mark to go by , as it you don't get it right , one side will be longer than 12 inches .
The starting point needs to be at the center of the first bend , that started as a blunt end .
It's like said above practice and practice .
90 Degree bends .

Dad is a retired electrician.
He can do things with a bender and a piece of conduit that will make you think it is some kind of magic trick

Not as simple as it seems to those of us who don't know

Wolf you should be able to find something on youtube, even if you search bending conduit that will get you headed down the right rabbit hole

Here's where I would start to determine the free length of the rod (identifying the material consumption or your radius) and then as mentioned- fixture with stops for consistency.

That math doesn't add up to me. 4- 12 inch sides would be 48 inches. If you are adding 1.5 , you shouldn't be at 46.5?

I'm talking a hand held torch....like a plumber would have in their tool bag. Map gas (yellow colored tank/bottle) burns hotter than regular propane, and it wouldn't take long at all to heat that small of stock to red hot.......a few seconds or so.

Read it a couple times , it will come out at 48 inches.
46 1/2 plus 1 1/2 is 48 .

I read it wrong. I thought you were saying to add an inch and half to account for the bends. As in 48 add 1.5 for the bends.

My bad.