Chassis and roll cage design, tube bending

Yup. Fastest way for a one off part. believe it or not. I have lots of other tools, up to a 3D solid modeler and I still usually do the main hoop for a car on the floor, because it allows me to place the bent part over the sketch to check it for accuracy.

Now that I'm old, I'll sometimes use the top of my fab table if I can get it clear, just so I don't have to crawl around on the floor.

 

If I may, there is not a software suite in the world that will make up for experience and fab. time. But from a business stand point I would go with SolidWorks. Like anything once your designer (dude in front of the comp.) get the ins and outs of SW I think you will be amazed at the wide range of things that can be done. It might sound like a commercial for SW but I have use Pro E, AutoCAD, Auto Desk, and SolidWorks. And they all have their pros and cons. Just my two cents (actual worth .0034 cents)

 

Do you have a hard time applying Solid Works to actually bending the tube?

 

This thread reminds me of a MT story I read once. Mickey Thompson was being presented an award from the ASAE and at the awards ceremony he told the audience that a hotrodder would have a ch***is laid out on the floor and half finished by the time an engineer would have the ch***is designed. I wonder how that went over?
Lots of different ways to skin a cat.
Larry T

 

Like everything it will take some getting use to. But you can make each frame rail, bar, and hoop individually and then ***emble and constrain in what SW call an "***embled Drawing". You can draw a bar apply it to your ***embled drawing check it for fit. Once you have it the way you want it you can print a dimensioned drawing of that bar, walk it out to the shop and get to bending. So no I haven't had many troubles with the actual application of what I have drawn.

 

It depends on the project & the customers Budget.

Almost anything can be built using any & all of the above methods.

Mickey was correct about the hot rodder being much quicker than the Engineer,
But even the Mick had some fabrication & design disasters - it takes time, experiance & money to do it right - ch***is, suspension , brakes & roll bars are no place to be wrong.

 

If someone is new to it, I second the Pirate4x4 link on page 1 of this thread. I have a bender with a hydraulic ram mounted to it. I do the pencil and paper.

 

I have more sharpie marker drawings on the floor of my shop than concrete! Chalk works too but I always smudge it. I also use big 4x8 sheets of cardboard. Draw on it, cut out the shape, and use it as a fitment guide/template to make sure everything has clearance and lines up before you start cutting & bending up expensive tubing.

 

I did sketches on paper then ripped 2X4 to 11/2X11/2 and screwed it together with sheet rock screws. Found out real fast that things that looked good on paper wouldn't work in the real world.

 

I hear that......

I deal with engineers and "inventors" quite a bit that call in that will design some impossible mandrel tube bending project on their computer and want a rotary draw bender to make the part.

That's almost a daily call around here.

 

I've never heard of the chalk on the floor method. But I like it.

 

I used chalk on the shop floor when I built this "striped in steel" gate a few years back...

 

Hey, it's "Traditional", therefore required!

 

Mickey Thompson built the Challenger that way IIRC (and I'm sure innumerable others have done likewise).
.

 

Nice ornamental work!

 

I would guess chalk on the floor is the oldest method. Got a kick out of the old guy using his bench, that's what I do too. Lay it out on cardboard first and the try to copy it. Looking foward to trying to use a program soon. By the way, Shane, happy to see stuff still being made here, it becomes more important every day.

 

tape measure, notebook and a pen.

 

Long time ago, engineering wanted to become "professional" and the loss was in part, the intuited feel that Mickey as a fabricator, was raising. It's a real challenge to know the numbers (engineering) and create a sound "design" (fabrication)...both disciplines serve the craft. We rodders do well to manage or explore these avenues. To build something and then overload or bend it (***ume steel here...) is the best learning!

 

5/16 steel line will work also. Just mark the center line and flip it.

 

Snapped lines and radius's out on floor.

 

a lost art nowadays with autocad and solidworks

 

Actually, CAD tools do nothing to replace a tape measure and sketches.

When I build something I start by measuring what I have and visualizing what I want to put there. Doodles in a notebook and measurements have to come before you can do anything very useful in CAD.

I've used Bend-It in the past, and it didn't help me all that much. Measure, make some test bends and have at it.

I'm a big fan of SolidWorks, and I use it whenever I can to refine a design, but for fitting roll bars or crossmembers or that sort of thing it's not as useful.

What I REALLY find useful is drawing out brackets. I used to do that with Dyekem, calipers, a french curve, etc. Then I started doing it in a simple drawing program and printing it full size, sticking it on the metal stock, center punch the holes and bandsaw it out.

 

Tape measure and a sharpie wasn't on your list. that's how i've been doing it for years. Once you get comfortable with your bender it gets fairly easy over time.

 

I have Bend Tech Pro on my computer at work. I like messing around with it on my lunch.

 

Yep, I use brake lines, sometimes a welding wire. Just bend it on the tubing die for the same radius and remember it's the inside or outside radius.

To all that already said it, yes it does get faster and easier the more you've done.

 

I did do this once. I had a 27 Dodge body and wanted to build a frame that fit it right under the edge of the body. I traced around the body with chalk on the garage floor and used that as my template for the frame. It fit,

 

Chalk on the floor works well for most of us. The hardest part was getting the main hoop mocked up and tacked in. With a little shop math, we could pre-bend most tubes from there and be real close to what we wanted.

One good formula that will help is: .01745 x neutral axis radius x degree of angle. This tells you how much tube is consumed in the bend. The neutral axis radius is the inside radius (same as your die radius) + 1/2 the tube diameter.

Basic rule of thumb is to do the *****iest bends first and trim/fishmouth the straight ends last.

Bob

 

All of the above, really all of it.

You have to cycle between imagination, paper, theory, and real life all the time. I say cycle because it isn't a one-way, linear process. Each part has a medium that works best for it. And it's equally important to keep flipping between small-scale and large-scale, close-up and big-picture.

The chalk method is cool, except that it's very easy to visualize wrong. Using CAD to figure out what you're going to set out with chalk or whatever means that much more geometrical intricacy becomes possible without things clashing.

 

1 1/2 ABS pipe mock up, then take it to some one with a tube bender, the 90s and 45s are the same radius and the ABS is the same out side diameter as 1 3/4 steel tube.

 

Chalk floor ....... yes I agree with Mickey

In my old shop we had screws in the floor so you could "string" things square.

As far as I know there is no way to "Program" good sense

Everytime I see this box screw up I laugh thinking computers are a design tool.

Use your laptop as a plump bob .......... sorry no.