I am needing to make a couple of multi-plane bends for the buggy frame that I am building, and have had a really hard time figuring out how to pull some of these bends off.

The piece of tubing that is giving me the hardest time is my A-hoop. My problem is that I want it to come straight up a", then in one bend I want the tubing to lean back b* and in towards the center c*.

How do I find out how many degrees to bend the tubing to accomplish both of the angles that I want from one bend? Then how do I find out how many degrees that I must rotate the tubing to make the one bend meet both dimensions that I am trying to accomplish?

For example, Say that I want the tubing to come straight up 22". Then in one bend I want to accomplish 12* of bend to the rear of the vehicle, and 5* of bend to the center of the vehicle.

Also, after I have that bend finished, how do I set up the tubing for the next bend(obviously you would subtract the 5* of inward bend from 90* so that the tubing would be horizontal).

I feel stupid, because I think I should be able to figure this out myself, but instead of bending tubing I have been bending my mind. If I had a CAD program to work with this would probably be easy to figure out, but I do not have that.

Maybe it is time for us all to come together sharing knowledge for a "Bending part II a guide for doing complex tube bending" for those that have outgrown Bending 101.

Thanks,
Sean

Bending 202! I like it! :D

How are you planning to make a multiple plane bend on the same area of tube...? Or am I missing something?

Seems you could take the Bending 101 layout and change its orientation. In a sense, build a box and use the same principles as a flat bend. Each side of the 'box' can be it's own section on the "layout table". I think.

Paul

No CJ that didn't help.

Does this help?

http://www.carrlane.com/trigbook/images/sine.gif http://www.carrlane.com/trigbook/images/cosine.gif http://www.carrlane.com/trigbook/images/tangent.gif

http://www.carrlane.com/trigbook/images/righttriangle.gif
http://www.carrlane.com/trigbook/images/righttrichart2.jpg

http://www.carrlane.com/trigbook/images/obltriangle.gif http://www.carrlane.com/trigbook/images/obliquetrichart.gif

No, that still didn't really help, but the last chart is nice. It saves me allot of time trying to remeber how to do trig.

All of that still applys to one plane. I know through a series of using those trig forumals lies my answer, but THAT is where I am needing help.

I am trying to figure out how to make a bend that travels a distace in multiple planes in relation to the structure that is around it. Yes obviously the single bend that I described is all in one plane , but once that bend is tied in with the rest of the hoop, it becomes quite the difficult bend to figure out.

Sean

there is a good calculator available from these folkstube calc (http://www.advancedtubular.com)

Bend it back wards. Bend the two angle bends in the hoop first. so that the hoop has the correct slope outwards from the top down. then set up for a strait leg bend but rotate the hoop for the correct angle of the down/leg bend. it should be a 90 squared with the top horizontal.

This will be awkward to bend, get some extra muscle to help hold it.

Try using 3/4" conduit to practice with. It's cheap.

Already have a full scale model welded up in my Garage JR:) . So I am not the only one! I have also reccomended this to people.

The problem is that a the model I made showed me a few things that I want to change. I had it all in paper, and it looked good, buit once I actually made it I found things I wanted to change.

I made my model Halo style, but I want to make the real thing hoop style. I want my A,B and C pillars to all lean into the vehicle the same degree. The problem is that my A pillar also leans backwards. That is where the problem lies.

But I agree with you JR. The conduit model is something I would not skip if you are going to be building your first rollcage/tube frame. I learned ahead of time things that I would have been mad if I had made it that way out of my chromoly. I know exactly how many feet of tubing that I am going to need. And while I am making the real thing, I always have something to go compare with. It also saved me from wasing sevel houndered dollars of tubing with mistakes. All of this came at a price of about $40.

Sean

Originally posted by ItsaCJ6
Bend it back wards. Bend the two angle bends in the hoop first. so that the hoop has the correct slope outwards from the top down. then set up for a strait leg bend but rotate the hoop for the correct angle of the down/leg bend. it should be a 90 squared with the top horizontal.

This will be awkward to bend, get some extra muscle to help hold it.

THATS IT!! Thank you. I can fully pull that off.

The reason that my mind got stuck on the bend on the pillar was that I was originally going to try a leg style front cage where the A-pillar bends back to the B-pillar.

Thank you ItsaCJ6 , you have finally helped me to get my mind in the right gear as far as the hoop goes.

OK, say I was going to do it leg style; How would you do it then?

Thanks,
Sean

OK, I'll give it a try the way I understand the bend your doing.

First there are tools that would help:
anglefinder:
http://www.vansantent.com/images/prod_anglefinderII.jpg
dial angle finder:
http://www.vansantent.com/images/ALBsm.jpg

I got mine here: Van Sant Enterprises (http://www.vansantent.com/angle_finders.htm)

They do have some bending software that looks decent:
http://www.vansantent.com/bend_tech_software.htm

I ordered the demo software to check it out, but haven't needed software yet.

Now to the bend at hand. Sounds like you want a A pillar hoop to angle in towards the top. Heres how I'd approach it.
First determine width of hoop at the top. Then take a short peice of scrap and an angle finder and angle from dash to the point it will meet at the top of the hoop. This will be the angle of the top bends. Use the bending 101 method if thats what you've been using to find the start of each bend. Bend the two top bend in a stick on the same plane, adn leave enough for the rest of the hoop on both sides.
Then get a friend or two and hold the tube where it is going ( top of hoop) and make a mark in the tube where the next bend should start. Then take a sheet of flat steel and hold against door pillar (where center of tube should end up) and so the sheet is pointing at center of tube (angled away from vehicle). The tip (edge) of the sheet will be where the inside of the bend should be. To set in die locate the top of tube 90 Deg from inside of bend. The angle of the bend will be the angle of the laid back hoop as viewed from side of vehicle.

One note of caution: This is worked out in my head,I have done bends like this but hard to explain over the net. Besides everyone has to kinda figure bending out for themselves to find out what works for them with the tools they have. I would use bending software if you had it. I do believe it will work tho, but can't make guarantees. :D

Hope this makes sense and works!

Originally posted by cruiserrg
OK, I'll give it a try the way I understand the bend your doing.

First there are tools that would help:
anglefinder:
http://www.vansantent.com/images/prod_anglefinderII.jpg
dial angle finder:
http://www.vansantent.com/images/ALBsm.jpg

I got mine here: Van Sant Enterprises (http://www.vansantent.com/angle_finders.htm)

They do have some bending software that looks decent:
http://www.vansantent.com/bend_tech_software.htm

I ordered the demo software to check it out, but haven't needed software yet.

Now to the bend at hand. Sounds like you want a A pillar hoop to angle in towards the top. Heres how I'd approach it.
First determine width of hoop at the top. Then take a short peice of scrap and an angle finder and angle from dash to the point it will meet at the top of the hoop. This will be the angle of the top bends. Use the bending 101 method if thats what you've ben using to find the start of each bend. Bend the two top bend in a stick on the same plane.
Then get a friend or two and hold the tube where it is going ( top of hoop) and make a mark in the tube where the next bend should start. Then take a sheet of flat steel and hold against door pillar (where center of tube should end up) and so the sheet is pointing at center of tube (angled away from vehicle). The tip (edge) of the sheet will be where the inside of the bend should be. To set in die locate the top of tube 90 Deg from inside of bend. The angle of the bend will be the angle of the laid back hoop as viewed from side of vehicle.

One note of caution: This is worked out in my head, I would use bending software if you had it. I do believe it will work tho, but can't make guarantees. :D

Hope this makes sense and works!

I understand what you are saying. Boy that sounds hard! Yeah I think that I will stick to theAdvanced Tubing Calculator (http://www.advancedtubular.com/) that AIRZUKI posted. I have been using that from the start. I read the bending 101 method, and used it a bit, but I found using trig was easier for me than laying everything on the floor.
The free tube bending software made it even easier!!
I really recommend it.

I did allot like you mentioned though, by figuring out target dimensions that I wanted to meet, then using trig to find out what angle it took to meet each target.
I started out knowing that I wanted the top of the cage 5" narrower than the body, not that I wanted a 12* inward bend in the pillars.

Man, I have been drueling over some of those Van Sant tools.
I definitely could use that dial angle finder that clamps on to the end of the tube.

Thanks,
Sean

Yeah those tools are sweet, I just got a shipment from them last week to help with my tube chassis project. I got the dial angle finder w/clamp and the angle finder above. Also picked up a pipemaster to help with difficult notches, and some tube welding positioners. They are sweet too, esp. the pipe master that thing rocks for notching a tube to fit in a difficult spot.
http://www.vansantent.com/images/pipemaster2.jpg

Heres where I'm at on my chassis as of today:
http://webpages.charter.net/cruiserrg/images/toypuproject/image071.jpg
Kinda dark but you get the idea. Good luck on your project!

Originally posted by Station


THATS IT!! Thank you. I can fully pull that off.

The reason that my mind got stuck on the bend on the pillar was that I was originally going to try a leg style front cage where the A-pillar bends back to the B-pillar.

Thank you ItsaCJ6 , you have finally helped me to get my mind in the right gear as far as the hoop goes.

OK, say I was going to do it leg style; How would you do it then?

Thanks,
Sean

easy

bend the B pillar top bend so that you have a 90. Then set for the first of the leg bends of the A pillar. rotate the bend the same amount/angle of the slope out to the lower leg bend then set for the lower leg bend and bend the same amount/angle but it should be rotated to be parallel to the B pillar.

Now these will be off set by the slope/angle of the first bend of the A pillar. they will not look right and they will try and roll in the bender. keep in mind that you want a parallel A lower leg and B

Originally posted by ItsaCJ6
keep in mind that you want a parallel A lower leg and B

Keep the lower legs of the A and B pillars parallel? Why?

Paul

Cool cruiserrg!! So those pipemasters really are nice eh? Are they worth the somewhat high price? Do you think that htye would continue to work well with allot of use, or would they wear out?

I am definitley going to be ordering some stuff from them soon. Actually, I want all of the same stuff that you got. The tube holding , welding fixture is definitely going to come in handy.

So is that the bottom of your buggy turned upside down?
It is amazing how quickly it starts to look like a buggy once you add a few key sections. When I built the conduit model of my frame, I kept on stopping, and just staring at it for like an hour just imagining the possibilitys. I already had everything layed out on paper so I knew what had to be done next, but I kept stopping and imagining the finished product.

It took me about a week and a half of after work bending welding sessions to build my model. I think I will actually build the real thing a little bit quicker, because I know exactly what I am going to be doing this time.
hehe... and maybe this time I won't keep stopping work just to stare at it.

Thanks again,
Sean

Originally posted by nasvik


Keep the lower legs of the A and B pillars parallel? Why?

Paul

I was planning to have my lower hoops paralle, but that is just because that is my visual preference. I am with you; I don't see any reason why they would have to be parallel.

Sean

Originally posted by nasvik


Keep the lower legs of the A and B pillars parallel? Why?

Paul

Ok they could be anyway he wants them, I am only ASS-U-ME-ing that he want's the last portion of the side hoop ( A Pillar) to be parallel to B pillar, to make both of them 90 degres to horizontal.

I am again assuming that both A and B pillars rise up from the floor or frame at a 90 to the horizontal plane.

Oh good! :) I was hoping there wasn't some physics thing I couldn't figure out. I will have my A and B pillars mostly parallel, but just because that's where they fit. :D

Paul

Station,

Yeah the pipe master works good. They are high priced, I just got the 1.75 because thats the only size I need it for. I think they would last long if taken care of, the pins are narrow so care should be taken not to drop and bend. You basically are just getting the layout of the nocth and transfering it to the tube. Just like a round contour gauge. I do wish it would have come with a case, tho I think if you get the kit it comes with a case. I just found on my last project that the notches to line up with a bent area or offset were difficult to transfer to the tube to notch properly. This is the ticket to get a tight fit with the tubes.

Yes my chassis is upside down, just frame rails, drop for transfercases, and motormounts. Finished the part for the tranfercases, link attachments today. I like welding stuff upright when possible, and having the chassis flipped like that makes it easier.

I totally hear ya on the stop, stare, and scratch your head time. I didn't do a model like you so my going is slow to figure out where everything is going to go. I have drawings, but most is in my head. I would say that most of my time is spent measuring, leveling, and squaring everything up. Be patient it takes a lot of time.

Originally posted by ItsaCJ6
Bend it back wards. Bend the two angle bends in the hoop first. so that the hoop has the correct slope outwards from the top down. then set up for a strait leg bend but rotate the hoop for the correct angle of the down/leg bend. it should be a 90 squared with the top horizontal.

This will be awkward to bend, get some extra muscle to help hold it.

I have been thinking about this; When I set up the lower bends on the hoop I am going to have to setup the bender to bend inward a little bit to counteract the spreading of the legs.
How do I figure out how much to bend inward so that my lower legs end up perpindicular to the top of the hoop. You say" then set up for a strait leg bend but rotate the hoop for the correct angle of the down/leg bend. it should be a 90 squared with the top horizontal. " , which tells me what I already knew without telling me what I need to know. How many degress do I have to rotate the tubing at a given angle so that it ends up perpindicular to the top part of the hoop?

Sean

Station,

I did some thinking, and I think this is what you need to figure it out.
http://webpages.charter.net/cruiserrg/images/bendinfo.gif

I drew it up fast so its not to scale, but should allow you to solve for the rotation of the tube to make the lower part of the hoop perendicular.

HTH and is correct. And I said I would never need Trig or Geometry after HS :D

ok possibly I just think in 3D. the drawing cruiserrg has made shows the finished hoop. Now look at the b2 drawing, pretend the lower leg bends havent been made. so you have an upside down U shape with spread legs. You will be bending it back from that outward bend since you want it to be 90 from horizantal for you lower leg. So if look at both drawing B1 and B2 you will see that the lower leg is 90 degrees to the horizaontal top bar in both planes.

Measure down to the point where you want the leg to bend back, then set up as if you were going to put a strait bend in the hoop at that point, but rotate the whole hoop in the bender to get your angle of the leg B1. This is how you get the compound bend.

Now keep in mind that you want the leg 90 to the top bar. like you pointed out that is has to bend in slightly. this will be accomplished all at once, if have rotated the hoop correctly, for the compound bend

Use your program to figure all the angles you need, for your application. this is just how to bend it simply.


Clear as mud. sorry its one of those things i just do.

Originally posted by ItsaCJ6
ok possibly I just think in 3D. the drawing cruiserrg has made shows the finished hoop. Now look at the b2 drawing, pretend the lower leg bends havent been made. so you have an upside down U shape with spread legs. You will be bending it back from that outward bend since you want it to be 90 from horizantal for you lower leg. So if look at both drawing B1 and B2 you will see that the lower leg is 90 degrees to the horizaontal top bar in both planes.

Measure down to the point where you want the leg to bend back, then set up as if you were going to put a strait bend in the hoop at that point, but rotate the whole hoop in the bender to get your angle of the leg B1. This is how you get the compound bend.

Now keep in mind that you want the leg 90 to the top bar. like you pointed out that is has to bend in slightly. this will be accomplished all at once, if have rotated the hoop correctly, for the compound bend

Use your program to figure all the angles you need, for your application. this is just how to bend it simply.


Clear as mud. sorry its one of those things i just do.

Hmmm. That was still a good way of telling me everything that I already know , without telling me the one little buit that I need to know.

I will go back over it to show what I mean.

Originally posted by ItsaCJ6
Now look at the b2 drawing, pretend the lower leg bends havent been made. so you have an upside down U shape with spread legs. You will be bending it back from that outward bend since you want it to be 90 from horizantal for you lower leg. So if look at both drawing B1 and B2 you will see that the lower leg is 90 degrees to the horizaontal top bar in both planes. [/B]

OK , yes, that is what I want. I know that.

Originally posted by ItsaCJ6 Measure down to the point where you want the leg to bend back, then set up as if you were going to put a strait bend in the hoop at that point, but rotate the whole hoop in the bender to get your angle of the leg B1. This is how you get the compound bend. [/B]

A straight bend in the hoop?? Never heard of a straight bend.
Just Joking, I know what you meant, but a bend in which direction, parallel or perpidicular to the plane of the top of the hoop?
"but rotate the whole hoop in the bender to get your angle of the leg B1. This is how you get the compound bend."
Yes that is obvious, but my question was to know HOW MUCH to rotate the tubing so that when I bend x* backward, I will get y* bend sideways. The more I am bending in the backwards direction the less I have to rotate the tubing to correct the spreading of the legs.

Originally posted by ItsaCJ6 Now keep in mind that you want the leg 90 to the top bar. like you pointed out that is has to bend in slightly. this will be accomplished all at once, if have rotated the hoop correctly, for the compound bend.[/B]

Exactly... I know it will travel the desired distance/degrees in both planes if I rotate the hoop correctly. What I need to know is how do I rotate the hoop correctly?

cruiserrg You are moving in the right direction, but isnt the formula incomplete? That formula should give me the ammount that I have to bend the tubing, but not how many degrees that the bend must be rotated if I am reading it correctly. I may be wrong, I will have to look at it some more.

Thanks,
Sean

Originally posted by Station
cruiserrg You are moving in the right direction, but isnt the formula incomplete? That formula should give me the ammount that I have to bend the tubing, but not how many degrees that the bend must be rotated if I am reading it correctly. I may be wrong, I will have to look at it some more.

Thanks,
Sean

Ok, The formula above will give you the degree of rotation for the tubing. rotate that angle one direction for one side then the oppisite rotation for the second. be sure you know where you started rotation from, and then for second one go back to start and rotate angle other direction. I believe the rotation angle should be clockwise for drivers side, and counter for passenger side. This is with hoop feeding the bottom into the die and top behind as you are looking toward bottom of hoop. (hope that makes sense, you will be able to envision it with the hoop in the die, you may also need to add or subtact 90 or 180 deg to get it in the right orientation, You'll know when its positioned in the die).

As far as the angle to bend, using figures from above pic I posted. need to find hypot. of last pic(length of red line). hyp= srroot of b2srd + b1srd. Then with hyp know formula for bend angle will be tan(angle)=X/hyp. Then take that angle add 90 deg and subtract from 180 to get bend angle. SEE MODIFIED PIC BELOW:

http://webpages.charter.net/cruiserrg/images/bendinfo2.gif

I hope this helps. Since it sounds like you modeling out of conduit try it with that first. Like I said before its in my head. I actually prefer figuring it while I bend so I can picture the way the tube is bending. Its also hard to describe over the net.

Hope this helps

Ok I didnt look at any formulas so I am sticking my neck out...

I think what you need to know is that when you rotate the hoop up, its angle should equal that of the outward bend.