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belchfire 12-16-2012 12:02 PM

frame weight
Back to this topic again. My 5x5 tube ended up having a 3/16" wall and weighs a ton. My biggest concern is torsional ridgidity. Ladder frames are the worst type but that's what I've got to work with. I thought of going with two 2 1/2 " dia tubes space frame style but they end up being the same weight as a single piece of 6x3 tube. I'm running a '97 T-bird rear IRS and an '06 crown vic front susp. I'm thinking of running the 6x3x.125 tube as the main rails with 3x3x.125 tube extensions front & back. I want to put an X through the center too. The large tube should greatly increase stiffness but because of its size I can go with the thinner wall. I don't want my Studebaker truck to weigh more than 3500 lbs. Stock was 2900. It will run a beefed 300"-6 so no super power. I see a lot of frames made from 2x4 beer can but I can't imagine them being too stable. I calculate that the frame should weigh around 450 lbs. How does that compare to what's normal? By the way, 5x5x.187" would add another 80 lbs.

NEW INTERIORS 12-16-2012 01:05 PM

Here's a frame I did for my 41 willys.. 2''X4''X1/8''

5''X5''X3/16 Will be strong enough to build a tank on it... My thought on this is way to big for what you want to build.. I do use 3/16 wall sometimes on a smaller car to give some weight to the car.. I'm not sure what your weight will be.. But I think a 20' 5''x5''x3/16'' is 240lbs by it's self..My willy's was 2''x4''x1/8 wall tubing..Most of the frames I build are 2''x3''x1/8 or 2''x4''x1/8 and sometimes 3/16''.. Did you draw your frame up on paper ?
I can tell you this much.. I think it will be heavy..

belchfire 12-16-2012 03:47 PM

5x5x3/16 is 185.4 lbs/20'. 6x3x1/8 is 143 lbs/20'. and 2x4x1/8 is 91.6 lbs/20'. If I build it from 3x6 instead of 2x4 it will be about #100 heavier. I'm wondering in the grand scheme of things that the extra ridgidity is worth the additional weight. Your frame is a basic ladder construction with additional tubular parallel members. With all that pipe doesn't the total weight almost add up to the same thing as I have? And there seems to be minimal cross bracing so how is torsional flex? Lots of research on chassis design and this type is on the bottom of the list. Just trying to make the best of it.

NEW INTERIORS 12-16-2012 04:35 PM

Not to sure how your adding this..:D
BUT 5''X 5'' X 3/16'' Is 11.97 weight per foot..

11.97 X 20= 239.4

Here it is..Structural Steel Tube, square and rectangular tube, tubing, steel pipe, I-beams, angle channel, wide flange beams

NEW INTERIORS 12-16-2012 04:38 PM

triangulation is the key when building something like this.. Not how heavy the iron is..

belchfire 12-17-2012 08:18 AM

You're right, I looked at the wrong line. Think I'll make a trailer out of that.

NEW INTERIORS 12-17-2012 08:24 AM


Originally Posted by belchfire (Post 1623714)
You're right, I looked at the wrong line. Think I'll make a trailer out of that.

I thought you was adding Alum for a Min...:thumbup:
Just seems a little much for what you wanted to build..;)

belchfire 12-20-2012 09:31 AM

frame weight
I had entertained the thought of using a '97-up dakota frame as it has the wider track which the Studebaker has. I decided against it mainly for the damn 6 bolt wheels. Ford hubs don't fit and I lost my access to a mill so I can't re-drill them. The frame is some huge hydroformed monster that''s got to weigh a ton. It's also 6" deep.
The difference between the upper and lower mount on the T-bird rear is 6" so that kind of dictated the size. I thought of making a tube space frame as that would look very cool but by the time I had it all fabricated, I'd have about as much metal as the 6x3.
The crown vic was chosen because it's R&P and 12' disc brakes. It's also a complete unit so I don't have to fight with some Mc pherson monkey motion. It just happens to be aluminum. There's an extensive article on ford truck enthusiasts website about a conversion and it looks pretty trick. Actually not an advantage because now I have galvanic issues to deal with.
I don't mean to sound insulting to those rodders with beer can frames.
My first project was stuffing a 390 in the Stude. It had worn mechanical drum brakes & armstrong steering and what are shocks? It was scary fast but only by the grace of God am I here to tell you about it. Now I want something that is predictable and responds to my commands. Most importantly, I want to show that old iron can smoke some fancy new looser cruiser.
What I really,really want to know is what is the normal weight range of a 1/2 ton truck frame? Bigger is better (size not weight ) but if the difference is substantial, I will adjust accordingly.

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