Hot Rods Elliptical Tubing for Frame Rails

Im just getting started on this new project And would like to start by getting the chassis started. I’m having difficulty sourcing the elliptical tubing I need to re create this hot rod. I didn’t think it would be this much of an issue sourcing it but it’s proving to be very difficult to find. So far I’ve actually only found one place that said they could produce it but it costs 3K for them to tool up for a run plus the cost of the product. I’m not totally against doing this but they also said they are 8-10 weeks out as well. So a few thoughts I have are, if I have some made would there be enough demand to have some extra made that I could sell to help offset the costs? Then I would need to spec out the tubing itself. Off the top of my head I figured it would be made from 3” DOM and probably .095 wall would be sufficient in strength? I believe this would end up with tubing that would roughly be about 2” by 4” give or take? Maybe some of the chassis builder guys could chime in on this? In doing the research for this project It’s said that this tubing was used for PBY wing struts. I haven’t been able to find any specs on what that tubing actually was sized at but I would expect it was 4130. The car I’m building is only going to be for display purposes but I would want it to be of sufficient strength that it could be driven.
My next thought would be maybe I could take 3” tubing and run it through a set of dies and try to make it myself? I don’t know how hard this would actually be but I would expect it would take a good bit of thought to do it well. Anyways? Here are a few pictures of the chassis showing the elliptical tubing I would like to hear some opinions on what approximate size you think this actually is and what wall thickness it would take to be sufficient for this type of project. Maybe some other ideas on how to accomplish this or maybe locate some I haven’t thought of yet. I’ve been searching aircraft suppliers like McMaster ETC…. And googling tubing and steel suppliers. So far with no luck other than the steel mill in Louisiana I mentioned. I’ve found some exhaust tubing that is oval shaped that’s 304 Stainless I think, but it’s only .065 and not really the shape I’m needing anyway. Anyway, here are a few pictures that show the tubing I’m needing to duplicate I’d like to here some opinions on what sizes and wall thickness you think this would be and/or need to be to be structurally sound to use for a chassis like this. I would also like to hear what anybody thinks the estimated wheel base is on this car. I’m assuming around 104-110 maybe? Thanks in advance.

 

If you search streamline tubing rather than elliptical you might have more luck but I am going to guess you are not going to find much that is heavy walled. The idea is to be aerodynamic which usually adds the additional need of light weight for most applications I would think.
https://www.onlinemetals.com/en/buy/alloy-steel-streamline-tube
https://www.aedmetals.com/resources/streamline-tube-profiles
https://www.aircraftspruce.ca/catal...NbCTpgzYeIRcX4MVPeh56OA9UqNtvlmWsSqlRxzB3nWSu

 

Pretty sure I’ve checked all those already, AED and aircraft spruce for sure and Wicks aircraft I remember talking to. the streamline or aero tubing is more of a teardrop shaped profile, non symmetrical and the largest they have spec’ed is about 1/2 the size I need. But I’ll double check thanks for replying.

 

Have you looked into architectural suppliers? I see all kinds of strange shapes in buildings, but would most likely be aluminum or SS, and thin walled, but you never know.
While doing the layout for my speedster, I was surprised at the length of my wheelbase. I would say that a “normal” vehicle wheelbase would be between 100” and 110”. The wheelbase on my 80 Series Land Cruiser is 112”.
Had the C channels for my speedster made. 1 5/8” x 3 1/2” x 1/8” thk IIRC. Used mild steel and they are “flimsy” IMHO even with my crossmembers attached (although they are just bolted at the moment). Trying to stiffen up the chassis is going to be a challenge, but if you’re just looking for a static display, a “thin” walled section might suffice depending on the material, but I would try to keep it no less than 0.100”.

 

how about this. https://www.louisianasteel.com/oval-steel-tubing.html

https://www.louisianasteel.com/elliptical-steel-tubing.html

 

That elliptical option they offer is pretty sexy...

-rick

 

Yeah, I’ve talked to them, he was very helpful and said they would do it, they are the ones that are $3000.00 tool up fee and are about 10 weeks out. I may have to go with that, but I’m hoping to find some that’s cheaper than 175.00 per foot. If There would be enough demand for it I could have them run off maybe 5 sets or something and sell 4 sets to help offset the cost of the tooling fee.

 

I wonder if @cornfieldcustoms would have some ideas. Between his shop work and working with salt cars he may have a source or process?

 

Cheaper to weld up some long dies to press some round tube between? Would be even cheaper if you could do it in 4 foot chunks and weld them together. Or do you need a full length stick to pass tech?

 

Flatten round in a roller ? I worked at a shop that had a roller that could have done frame rail sized stuff. We sent bigger stuff out all of the time. Mostly box, round, I-beam and angles into curves and circles. I'm pretty sure a machine that can roll I-Beams could do it, with the right set-up. Mike

 

Have checked here
https://www.shapirosupply.com/

 

I knew a guy who had 4 PBYs in his back yard. All gone now. One went to a museum in Campbellford, they may know where you can find some spare wing struts.
https://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?t=4604

 

Thanks I have not tried them I certainly will though.

 

I just joined up to a PBY internet group hoping to at least get the specs/info on the tubing. I have a guys number way out in Oregon that says he has 2 struts but they are both pretty damaged and I probably wouldn’t be able to use them.. Thanks for the suggestion

 

I hope you find some. That frame looks really nice. I'm with you, I would want it to be able to be driven and even maybe good enough to drag race.

 

What about sailboat masts?

 

I work for a fence company, we use some pretty heavy rollers on our cantilever gates, I could try to turn them down in a lathe to get the profile but it will take a hell of a fixture and a lot of force to draw it through I’d bet

 

I’d like it to be strong enough to drive and be functional, but I don’t have any plans at this time to get the Ardun running. It hasn’t ran for 62 years. So at this point I’d be tickled just to have the car look accurate enough to put on display and show it. I’d be scared to death to drop a valve or something and hurt it bad, it’s supposed to have some pretty exotic parts in it for the time.

 

A few years ago, I think the Chassis Shop had elliptical 4130 tube. The kind of stuff they use on TopFuel rear wing struts. Be worth a look

 

I was thinking of a place more like this https://www.cmrp.com/ or this https://www.nisteel.com/steel-fabrication . One of these should be able to do it


A 3 1/2 round would be just about 2x4 if you flattened to 2 and ended up with ~ 1/2 round (1" rad) ends. It'll put a bend in it, a run through upside down should straighten it. Just a hunch, Mike

 

Man, both those places sound promising and are within a few hours of me too. I just imagined the machine that forms it uses a series of round dies on rollers that it feeds through like a big bead roller progressively getting smaller I donno?
That big roller is crazy!
. I appreciate your help, there’s gotta be someone that does this.. I have a machinist buddy that thinks we could just make dies and use a press and just do like a foot at a time. like Alchemy said

 

Mike I was going to suggest talking to Bob Boyce of Boyce engineering. He was instrumental in the tubing industry and with Indy car ,nascar and all sorts of racing .
Unfortunately looks like Bob sold the company but believe I may have his cell phone number.
What’s good is Bob innovations and machines we sold to
AEDMetals.com
And looks like they are still making aero tubing

 

https://coremetal.net/product/elliptical-tube/

 

https://www.ljtube.com/tubing/tubing-by-shape/oval/

 

https://tex-tube.com/elliptical/

 

I don't know about the tubing.
But that's one amazing hot rod.

 

Thanks John! Hope you’re doing well, I will check that out I think I may have checked with them but maybe I’m asking for the wrong tubing or something? I was gonna call you and see if you have some of the parts I’m needing. Mel and I are planning g on going to Torque Fest. You should go over for the day.

 

I’m working on those suggestions thanks . The guy at LJTUBE was very helpful and gave me a list of places to check with, but they have a minimum run of 30,000 feet to tool up. Which is the problem I’m finding at many of the placesI call that can produce it. I appreciate all the suggestions I’ll check out every one Thanks again!

 

I wonder if round tubing could be pressed into an oval shape with a hydraulic press.