I'm getting to the stage in my project where I need to consider my chassis design from the repeatability point of view. I wouldn't bother doing a mid-engined design of my own if I was only ever going to make one.
Anyone have any thoughts on how a jig could be constructed on which to make subsequent chassis? Naturally it would need to record in 3d the position of all the important points such as suspension pickup points , anything else, though?

I seems to me that 'jig' could mean anything from flat surface with a few clamping points, all the way to a complex structure which would position every tube. Question of where to stop, really, I suppose?

John

More questions really John.
What volume? how much do want to spend? what level of skill of user? how complete does the frame need to be?

Designing machines and consequently jigs and fixturing is my job so this is in my area of knowledge.

Basically, I'd go for a hefty spine..say 6" square, or beam section with stands at each end (on trunnions perhaps?)

Then use "ribs" of 3" square (maybe 2") to come out and locate suspension pickups, and key tube locating points.

Don't waste time "over-locating" trivial tubes...stick to the important key points.

Anyway just a few pointer for now.

HTH

On one of the episodes of A Race Car Is Born, Evans went to annoy some guy making chassis' in the W***field factory.

The guy said he was making a side-frame. He put a load of [CNC precut] tubes for the side of a chassis in a jig that was simply a flat board with a load of blocks on it. It then showed him fully welding some of the joints. Evans had a go and blew a hole in it.

Indicates that they may have simple jigs for different parts of the chassis, bottom rails, sides, etc and then assemble the whole chassis in sections. I guess they have some sort of jig to hold all the sections together nice and square before they weld it all together.

Any help?

Liam

[Edited on 30/10/02 by Liam]

Yes, both Alan and Liam's posts are helpful. I liked the Westfield approach, makes sense when they're making that many cars.
I used to use a lot of jigs and templates when I was guitar making, but car design (and the associated jigs) is much more 3 dimensional.
A good jig serves two purposes of course. One is to make sure each component goes in the right place, and the other is to stop components going in the wrong place........

John

Seems that space frames don't lend themselves to mass production considering all the hand fitting necessary to make them work.

I would think that for production purposes you could try to design jigs to do major subassemblies first. Then you could bring them together as needed to do final assembly. So there might be a pile of lower assemblies, a pile of uppers, a pile of front assemblies, and a pile of bustles.

From a QC standpoint it might be easier to control the process and if you happen to scrap something it doesn't affect the whole chassis.

Mmm!

Going with the W---field approach, it would probably be easy to use two main flat board jigs made from thick ply. Might even get away with one using both sides.
That would be for the main top and bottom rail assemblies.

Then small jigs made of same ply could be used for vertical faces, including suspension points. These could just be clamped into place as and when needed.

I suppose it all depends how complex you want to make the chassis.

Terry