Building your own custom frame?

[ProTour69GTO]

Hypothetically if one day I wanted to build a custom frame where do I start, is there books that I can read? I know I'll need to know how to weld which I plan on learning. Also the materials of coarse. I have googled car frame jigs and frame building and came up with nothing can any body point me in the right direction.

Thanks

[silver69camaro]

Whew that's tough. I guess I would ask, hypothetically, what background do you have? Fabrication? Engineering?

Any hypothetical goals?

[ProTour69GTO]

Well none just more curious than anything else

[jerome]

in a pro-touring application, knowledge of front and rear suspension theory is crucial. Milliken, "Race Car Vehicle Dynamics". If you get the gist of what he says, then continue. If you cannot grasp the idea of force vectors after studying, I would suggest you call Art Morrison and order a frame. I have no idea what your background is, but you need to be mechanically minded, decent at fabrication, and be able to understand static mechanics.

As for planning the chassis, pick a track width, ground clearance, and wheelbase based on the body. Pick what type of suspension systems front and rear (i.e. double a-arm and 3link) Plan out how to mount the body and drivetrain. Decide whether you want a spaceframe or a conventional ladder frame. Start building.

Of course, it's not that simple, but you get the basic design process. As for background, you really don't need any, but you need to be able to learn. I built my own rear suspension, and before I started, I had no knowledge or fabrication skills. However, I am going to school for mechanical engineering, so that helped with the static force analysis. I learned how to weld myself while on the project.

In terms of engineering ability, you are going to overbuild the frame anyways, so having an eye for what "looks strong" based on the most fundamental mechanical concepts is all you need. However, unless you plan on slapping in OEM suspension parts in OEM mounting points, you will need to understand how links transfer forces from the tires to the chassis, and the affect of moving these links around. You will also need to understand statics to figure out how to make the frame stiff. It is not easy stuff, the book about it that I mentioned is about 4 inches thick. Don't be discouraged though, you can understand it if you have a mind for that kind of stuff.

I would say, get started reading about frame design. Look at pictures of frames and figure out how they are designed.

[project hotrod]

in a pro-touring application, knowledge of front and rear suspension theory is crucial. Milliken, "Race Car Vehicle Dynamics". If you get the gist of what he says, then continue. If you cannot grasp the idea of force vectors after studying, I would suggest you call Art Morrison and order a frame. I have no idea what your background is, but you need to be mechanically minded, decent at fabrication, and be able to understand static mechanics.

As for planning the chassis, pick a track width, ground clearance, and wheelbase based on the body. Pick what type of suspension systems front and rear (i.e. double a-arm and 3link) Plan out how to mount the body and drivetrain. Decide whether you want a spaceframe or a conventional ladder frame. Start building.

Of course, it's not that simple, but you get the basic design process. As for background, you really don't need any, but you need to be able to learn. I built my own rear suspension, and before I started, I had no knowledge or fabrication skills. However, I am going to school for mechanical engineering, so that helped with the static force analysis. I learned how to weld myself while on the project.

In terms of engineering ability, you are going to overbuild the frame anyways, so having an eye for what "looks strong" based on the most fundamental mechanical concepts is all you need. However, unless you plan on slapping in OEM suspension parts in OEM mounting points, you will need to understand how links transfer forces from the tires to the chassis, and the affect of moving these links around. You will also need to understand statics to figure out how to make the frame stiff. It is not easy stuff, the book about it that I mentioned is about 4 inches thick. Don't be discouraged though, you can understand it if you have a mind for that kind of stuff.

I would say, get started reading about frame design. Look at pictures of frames and figure out how they are designed.


Well said.

Plenty of information exists to design something that will work well for your application. We're not really re-inventing the wheel so tried and true methods of suspension geometry are plentiful.

You can also mess around with scale models before moving up to full size materials to save money. Considering most of my current project is one off I am in the scale model process right now. It really work some aspects out that I thought worked on paper but wouldn't in the real world.

And, you can check out this thread for what it takes.
https://www.pro-touring.com/forum/showthread.php?t=36864

[greencactus3]

if you actually want performance gains, i would recomend keeping everything as adjustable as possible while keeping an eye on compliance issues.

if possible start off with tire data, and build upwards from there...

problem is.... tire data is not readily available

[gt1guy]

Hypothetically if one day I wanted to build a custom frame where do I start

Copy a design that already works.

And read everything you can get your hands on.

Kevin

[novanutcase]

Well said Jerome!

I think the first book you'll want to read before Millikens book is Herb Adams "Chassis Engineering". It will give you the fundemental aspects of chassis design and is a great primer to move on to Millikens book.

John

[Norm Peterson]

Hypothetically if one day I wanted to build a custom frame where do I startAt square 1. Deciding what you want the car to do, what competition rule requirements (if any) you'll need to satisfy, and what compromises you might be willing to make. Components and systems have to all fit, the body and sheetmetal needs places to be hung from, you do need to be able to get in and out at least reasonably easily, and you probably have to pass some sort of state inspection.

From a structural point of view, it's easier to make something strong enough than to make it stiff enough for truly hardcore PT driving or most forms of competition. It's also easy to overbuild the structure trying to make it stiff enough (read: heavy). Here is where a bit of structural analysis comes in, in addition to the modeling suggestions already posted.


Norm

[B Schein]

Hypothetically if one day I wanted to build a custom frame where do I start, is there books that I can read? I know I'll need to know how to weld which I plan on learning. Also the materials of coarse. I have googled car frame jigs and frame building and came up with nothing can any body point me in the right direction.

Thanks

Not to sound like a smart ass but if you seriously what to learn about this stuff go to collage get an Mechanical Engineering degree and join the Formula SAE team and you will learn so much about car design that it will drive you crazy My mind races all day with things I what to try on race cars. I guess it’s a good thing I am the team leader this year and get to implement all my goals.

[Marcus SC&C]

Start off by reading (and rereading and rereading etc.) Herb Adams Chassis Engineering and Carroll Smith`s Engineer to Win, in that order. Your first challenge is good design and fabricating skills. Suspension geometry,material selection and such will come in later on down the road. I`ve had the opportunity to work on a lot of custom chassis cars from road race cars to home built street rods. The most common problems are fabrication and simple design related. Weak single shear mounts,horrible weak welds that look like wads of old chewing gum,total lack of triangulation etc. These problems can be avoided with just a little basic knowledge,common sense and skill. To put it bluntly these are the kinds of mistakes most likely to make you crash.
:drive2:
Those 2 books will give you a good start. The rest of Carroll Smith`s books will also be a big help. But remember all the engineering and computer testing in the world won`t help you if your welds have poor penetration and break! I suspect that after reading up on the subject thoroughly you`ll decide that building a whole frame/suspension from scratch is not something you really want to do. Consider buying a kit or frame/suspension sections from Chassisworks or Morrision etc. and put it together. It`ll let you get involved in the frame fab process but help you to avoid the major pitfalls. Mark SC&C

[CraigMorrison]

While we do have a lot of weld in kits - inner "X" front and rear suspension, we also do custom bending all the time for guys who are doing their own thing. Don't want to cut and weld? bang us out a drawing and we can probably bend you a rail.