# Z Bender ??



## CalgaryPT (Feb 15, 2017)

Hey you machining types...have any of you ever made a larger scale version of one of these? It's a Z Bender used in the model plane field. There are also pliers that do a similar job.

But I was wondering if anyone has made a beefed up version of one of these for heaver rod?  I was thinking even on my mini mill I could machine a metal rod end that fits inside a pipe of 1/4" wall pipe. It would just need the pins on the side (one removable for 90 degree bends if needed). I need to do some Z bends on 3/16 or 5/32 rod and my bar bender can't do anything this narrow.

I know there are places where I could get them heat treated in Calgary if need be too.


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## Alexander (Feb 15, 2017)

Neat. Stupid question but what are you bending with it. 4-40 control rods is my guess but i dont really know. I have never seen a little bender like that before.


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## CalgaryPT (Feb 16, 2017)

Yeah, it is a neat little bender used for linkages. There are equivalent ones for small engine throttle linkages too. But I need BIGGER   I have a bunch of benders at my shop, but none of them will produce a short radius z bend on 5/32 or 3/16 stock. Even if you use a vise and heat the material, you're limited to the jaw thickness of your vise.  I build spray proof skunk traps, and I need a tight radius on the trip plate rods. I haven't built the above jig yet, but the design looks scaleable.  I once saw a die for a shop press that did a similar bend, but I can't find it online anymore. I know I can figure out other ways to do what I need to do, but it's now become a mission, so I'm hooked. The z bend looks neater than the old method I used of welding stuff together. 

I probably shouldn't start talking about RC stuff. I already have the electronics bug and don't need another expensive hobby.


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## PeterT (Feb 16, 2017)

There is this kind of principle which can make simple bends. Or if you keep winding the wire stock around the fixed pillar post, it was intended to make a coil section (old school RC landing gears from piano wire).
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXGFW4&P=ML

I think the issue you might face in Z bending 3/16" diameter rod is the metal requires a specific minimal bend radius, otherwise it fails in tension. There is probably a table of what this is out in internet land & then it would be a matter of sizing your fixed rod diameter. You should be able to just flip the rod & do the second bend the same way. A simultaneous Z bend (two 90's at same time) might require a lot of clamping force. I'm not saying it cant be done, but it will be a function of the material type.


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## CalgaryPT (Feb 16, 2017)

Agreed. And I do have one of these benders you ref. They are very handy. I just thought the design of the devoted Z bend one was clever. So now I am hooked and determined to make one. The radius is the issue as you point out, especially when trying to do by hand. I have some thick stock where Z bends were obviously made on a press, but I don't have the dies.

All fun stuff to contemplate. Thanks.


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## PeterT (Feb 16, 2017)

Hmm... I'm having a tough time finding a simple table of bending allowance for round rod. This is sheet metal orientated but seems to infer pretty tight inside bend radii. Could one infer a rod isa really narrow width sheet? http://www.americanmachinetools.com/bend_radius.htm

Funny, I've been collecting tubing bender plans & links & techniques for what I'll eventually have to construct for induction tubes & exhaust pipes for my radial. Tubing is real PITA even with all the filler tricks. But I would think solid rod is a bit more straightforward. Watch out for certain materials though as they can work harden. I think that's one of the mechanisms they fail while being bent.


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## CalgaryPT (Feb 17, 2017)

I got schooled big time when I bought my first bender. There's a lot of math and science to it you want to repeat the result. But its fun to learn. I admire people who can do it well. I'm still hit or miss.


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## Tom O (Feb 18, 2017)

Peter a member on MadModders is building a v8 demon bending his pipes starts on page 5http://madmodder.net/index.php/topic,8108.100.html . if you need some I have 4 lbs of cerrobend medical grade off ebay.


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## CalgaryPT (Feb 18, 2017)

OMG. Watching this guy work makes me want to crawl under a bed and hide. I really admire such skill. Thanks a million for the vid. He is many, many, many levels ahead of me. I would have made a great farmer....I can fab anything, or repair anything mechanical....just don't ask for pretty or tight tolerances.

(I did have a hydroponic farming op in my basement for a while....but it was for hot peppers. And my wife shut me down because she was afraid the cops were going to kick in our door. If I had lived in Arizona or New Mexico, I could o' been a Habanero contender!)

Thanks Tom. I'm half way to a Red Green solution to my problem...I will post when I get there.


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## PeterT (Feb 18, 2017)

Tom.O I might just take you up on a sample just to experiment. Are you using it for similar application yourself? I wasn't sure where to get the stuff but I'm a long ways off that stage still. Fortunately my curves aren't super radical. But that's what everyone says until they start kinking tubing. My exhaust stacks are 90-ish type radial bends that point rearward, maybe 1" long. The induction tubes are kind of funky though. They are maybe 3" long, start from the carb manifold in rear of engine & come up to the other side of the head so it looks like a 5-legged spider. I bought some 8mm brake line which is a softer alloy. But I will still have to make a die block bending assembly with forming wheels that have half-circle cut outs, kind of look like a pulley wheel.

Coincidentally cerrobend is what Terry used on his 1/4 scale Merlin for a tubing job. (He's getting closer now. I might actually wet myself when it runs)
http://www.homemodelenginemachinist.com/showthread.php?p=290843#post290843

The usual pipe bending drama I see often
http://modelicengine.la.coocan.jp/k070402.htm

Yes I've seen that V8 Demon, that guy (Doc?) is on the IC build forums. If you like the auto stuff, here is a Good'er 1/3 scale V10
http://www.modelenginemaker.com/index.php/topic,3007.255.html

And this 1/3 scale GrandPrix Mercedes Benz is going to be awesome
http://www.modelenginemaker.com/index.php/topic,5142.30.html


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## PeterT (Feb 18, 2017)

I know the OP was about solid wire bending, but if tubing ever comes up on the project list, there seem to be different approaches depending on the application. I've seen some miniature versions of this style with an adjustable slider block. Youtube *Useful Tools Mandrel Tube Bender - Mk 3*. (He also makes a neat swaging tool). I've also seen some simpler tube bending assemblies with wheels & axles or the Swagelock principle. The common denominator seems to be tool profiles that closely match the tubing OD. Sorry for the departure.


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## CalgaryPT (Feb 18, 2017)

Departure forgiven and welcomed Peter. When I made my comment about getting schooled, I was thinking specifically about tubing. Years ago I bought the JD Squared bender w/ the a/hydraulic option. People new to bending should watch vids such as




that really illustrate the importance of wall support and bend radius. The first time I saw a 2", 1/4 wall tube being bent I had an "ahh haa" moment that may me appreciate the math and engineering behind this stuff.


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## Tom O (Feb 19, 2017)

I bought this with my grandaughter in mind for holding iregular shaped rocks for drilling as well as being prepared for any upcoming holding / bending issues. My father worked in the dnd shipyard he told us of using rosin to bend the big pipes.


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