tube bending techniques

[Gen3_Teg_88]

hello all! i have been working with brake like and brazing for a while now. i have made some decent things with it, but i do it more as an "art" and less as a specific measured out science. i do measure of course, but i have a couple questions that i have been wondering about to be more precise.

say i wanted to make a "[" kind of shape and i wanted the two sides to be a specific height and the width to be specific, how would i measure/mark and bend tho make sure all the side end up where i want them and the correct length so everything is even?

the other thing i was wondering about is that brake line come in large rolls for fairly cheap, how would one make the tubing as straight as possible to make tube chassis and such?

 

[BigSki]

say i wanted to make a "[" kind of shape and i wanted the two sides to be a specific height and the width to be specific, how would i measure/mark and bend tho make sure all the side end up where i want them and the correct length so everything is even?

I struggled with this when I started making roll bars and roll cages, I finally got a simple, workable way of ensuring symmetry. I used graph paper and make a 1:1 drawing of all of the overall dimensions. I now concentrate on making the width of the '[' to the correct dimension then simply trim the length of the legs to the desired dimension. If I plan on making a copy of a certain shape at a latter time, I'll save the original part and use it as a template.

 

[SMR 510RR]

All benders are different and all tube or rod bends different so going on a whim and a prayer is not going to be you consistent results. There however is a very easy way, draw it out 1:1 on paper. Make a test bend with the same tube and the same bender, go to the maximum of your bender and make sure to mark the start position on the tube. Now you have a template that will tell you where you need to start each bend. Generally you start from the middle and work your way out, use your template tube and line it up with the corner and mark where the bend needs to start. Do that for all the bends, now drop the tube on the drawing line up your center mark and mark the first bend. Bend it, reference your drawing to get the angle right. Mark second bend. Bend it. Repeat as necessary.

Here is a link to a better write up on Pirate 4x4, while it is for 1:1 stuff the concept is exactly the same
Pirate4x4.Com - The largest off roading and 4x4 website in the world.

 

[bob1961]

best way is to just bend up a piece and see if ya got it right....only way to know where to mark your tube and put it in your bender is just do it....metal stretches as you pull it around die/mandrals and you just need to just do it to find out where you need....did i mention you just need to do it to find out where you , oh never mind just do it "thumbsup" ........bob

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[Gen3_Teg_88]

so i guess i will just go about it mostly as i have done it in the past, maybe a few minor changes. thanks for the tips!

any ideas on making the coiled tubing straight?

 

[greggreg2011]

so i guess i will just go about it mostly as i have done it in the past, maybe a few minor changes. thanks for the tips!

any ideas on making the coiled tubing straight?

you can always hop on youtube and watch info and i saw detailed stuff on here or scale4x4. its somewhere, i saw it awhile back

 

[bob1961]

any ideas on making the coiled tubing straight?

that's gonna be a tough one as i think it is a bit softer then straight tube is and if you work with straight lines you'll never get it straight........bob

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[hotwheels000]

any ideas on making the coiled tubing straight?

A pipe stretcher of coarse:mrgreen:

When I worked in the shipyards we would use a come-a-long attached to a solid object on one side and the other attached to the roll of tubing(usually copper).You would roll out the tubing and attach the other end of the tubing to something solid also. Then just start cranking on the come-a-long until the roll was semi straight....

Your best bet is to start with staight lengths,you will never get the rolled tubing perfectly straight.

Good luck"thumbsup"

 

[Gen3_Teg_88]

thanks for all the advice guys!

 

[LBTaco]

All benders are different and all tube or rod bends different so going on a whim and a prayer is not going to be you consistent results. There however is a very easy way, draw it out 1:1 on paper. Make a test bend with the same tube and the same bender, go to the maximum of your bender and make sure to mark the start position on the tube. Now you have a template that will tell you where you need to start each bend. Generally you start from the middle and work your way out, use your template tube and line it up with the corner and mark where the bend needs to start. Do that for all the bends, now drop the tube on the drawing line up your center mark and mark the first bend. Bend it, reference your drawing to get the angle right. Mark second bend. Bend it. Repeat as necessary.

Here is a link to a better write up on Pirate 4x4, while it is for 1:1 stuff the concept is exactly the same
Pirate4x4.Com - The largest off roading and 4x4 website in the world.

This is good advice "thumbsup"

I recently started brazing brake line and use these methods.

I've made rock sliders and a couple bad design bumpers, still working on that though.

good luck

 

[lead lobber]

When I was working on a tube design for my 1:1, I bought a program called Bend Tech Pro. Google it and check it out. Obviously it was made for full size rigs, but I'd guess you could reduce the numbers to 1/10th and be fairly accurate. Here is a pic of what I started with early on. The program will lay out a bend sequence, angles of rotaion, cut out templates for fishmouths at each joint. It is a great tool for visualizing what you want to build.
Eventually, the bottom was the result. Not too shabby. Now to finish it.

 

[rmdesignworks]

so i guess i will just go about it mostly as i have done it in the past, maybe a few minor changes. thanks for the tips!

any ideas on making the coiled tubing straight?

I straighten coiled tubing by cutting a piece to a little longer then the desired length....straighten it roughly by hand...then sandwich it between two pieces of plywood and start rolling the tubing back and forth between the two wood plates...a few seconds to a minute or so and most times the tubing is now perfectly straight. A rubber surface applied to both wood pieces helps a lot to grip the tubing as it is forced to roll better.

 

[rmdesignworks]

Tube bending and even rod bending can be helped a lot if you use center of bends...learning the angle of the bend and determining where the center of the back or outside of the bend is at the bender in relation to the two sides of the bend....this is how we bend conduit in electrical work...our one shot benders are marked with a "back of bend" on the "foot" and multiple bends can be made by applying marks to the pipe at certain points that have angular and spread distance added in....the Back of Bend is not the center of the bend though...the center of the bend can be found on the bender based on the angle of the bend....the center of the bend will be the intersecting points between the leg and stub of the tube or rod being bent...I use an adjustable angle finder and set the angle of the bend I want...I measure the distance from the first bend to where I want the second bend and align the angle gauge with that mark then bend. If I want the bends to be 4 inches apart and I am using 3/16" rod then the mark is made for inside center of bend but 3/16" is deducted from the distance to account for the thickness of the tube...the bends will now be 4" apart at the outside...give or take a few thousandths of an inch....using the same numbers on another piece of tubing will give the same bend...make a note of the numbers used for repeatable pieces later on...like for repair pieces.

 

[mntbkrguy]

I know this is an old thread but thought this would be the most appropriate place to post this. especially for those making a lot of tube chassis.

I don't have much experience in the RC crawling world but since I got my car I have beet curious about making cage or even a full tube chassis.

After making some new lines in my jeep I have a ton coiled brake line left over so after some searching I found this thread on making a straightener. I thought I would share just in case someone can use it. "thumbsup"

How to straighten coiled tubing - OFN Forums