Joined a few years back, posted maybe 4 times and then got lost. I've been restoring a bulldozer for about 2 years plus. Well I found my way back, so Greetings to all. I'm getting ready to start a build. I'll describe it as a mid 30's Indy race car, I have an in line 6 cylinder chey. Getting ready to pick up a pretty complete 37 Nash front end. Dropped forged I beam axel spindles, hubs, tie rods etc. I will be making my own frame. Cutting, bending, welding, tapering and so on. here is my question. 2 by 4 rectangle tubing, 1/8 inch thick or 2 by 4 channel maybe 3/16 inch thick. On the channel boxing where necessary. Parallel springs front and back. Probably use a ford 9 inch and a T5 tranny. I'll by 12 ft steel to have enough to work with. What do you guys think. The reason for my question is this. Rectangular tubing when through bolting for whatever reason will need spacers to keep it from pulling in so my thinking is I would need access holes to put in the spacers. With channel no problem, and then box it where it might be needed. Thanks for reading.
A 9" is overkill. You won't need from a power perspective so why not save a bunch of money and go for a lighter rear end. A lighter rear end won't absorb so much power.
Rectangular steel tubing wasn't "the thing" on those cars in that era. They used channel, but not the squared off corner stuff used in metal fab today, but rounded corner pressed steel.
Like mohr hp stated, early frame materials had rounded edges. That looks nothing like todays C channel available at my local steel supplier. Maybe, instead of 2 pieces of 2x4” tube, buy 1 piece of 4.5x4” tube. Split it down the 4.5” side and you have 2 2x4” channels with rounded edges. In your layout process use a fine tipped bright paint marker to show the cut line. Then setup a straight edge you can run your jigsaw along. I know it sounds crude but with some patience you can end up with nice straight cuts. I’ve done it before. If you stay with the 2x4” tube; if drilling through holes for a 0.5” bolt instead of drilling 0.5” holes drill 0.75” holes. Cut 0.75” dia. X 0.125” wall tubing to fill the previously drilled 0.75” holes. Weld the tubes in and no more distortion issues when you tighten the 0.5” bolts. But remember when using this tubing idea think about how you are going to protect the fresh weld/ bare metal inside that tube. If using tube, I would be comfortable using 0.125” wall. If using, or making my own, channel I would use 0.188” minimum. If the cross bracing was sparse or, I envisioned lots of power or, rough driving I would feel more comfortable using 0.25” wall material. ras
Before finalizing your frame depth, I would want to have the spring hangers you want to use since they may determine the required frame depth. I would want to use radius corner channel over rectangle tubing. Perhaps look around and find a 30's or early 40's car or truck frame as a start point. Or, buy reproduction frame rails st start with. Study some of the early Indy cars for ideas. Should be a fun project.
Considering most chassis builders use 2X3 .083 wall for drag race cars, I would think 2 X 4 X .125" wall would be more than enough. As a side note, the thicker the tube wall, the bigger the corner radius is. 3/16" would have a bigger radius than 1/8", 1/4" bigger still. One comment I have about splitting box tubing. Although in theory it sounds legit, all the times I have done it, the tube pulls out of straight. But, to qualify this statement, this was either 2x3 or 2x4 split along the narrow side. Big box tube like ras mentions may not do that. If you want it TRULY period correct, a lot of those cars had frame built from round iron pipe.
I'm using a late 20's Chevy frame on my boat tail that is supposed to end up looking like an old two seat race car. I rescued the frame from a rat rod dude and then because the rear panel had been hacked out pulled the rails in so the rear springs will be parallel to each other. The whole idea is that it looks like an early/mid 30s two seat race car when done.
When purchasing your steel, you will find that it gets less expensive per ft if you buy longer lengths, and also buy any other steel you need all at one time. The box tubing can probably be bought in a 40' length. Take battery powered bandsaw with you and cut it while its on your trailer. Figure what lengths you may need for crossmembers as well as side rails. Have them put the 40 ' on your trailer and pull out in the parking lot and cut 12+ feet off the end. With a 20' trailer you then have 8' or less sticking out the back. Cut a crossmember length from that and you have maybe 4' sticking out. Put a flag on it and strap it down. Helps sometimes to have a couple of old tires atop the trailer to set the steel on for strapping it to the trailer. Recently bought about $1200 worth of steel I beams and a 5x10 sheet of 1/16 steel for a neighbors workbench top. Saved about $300 by getting it all at once instead of multiple trips. Also, they delivered it since there was 2 40 ft ones and a 20' one. I'd stick with 1/8 wall if using a box tube and just put round stock thru both walls and weld it where you need attachment mounts. Really, you can just make 1" long plugs and weld them in one side at the place you need them for most attachment points. Just be sure you cut all pieces slightly longer than what you think you need and then shorten them to length as the project moves along.
The rectangular tubing would be stronger that a channel. What you are looking for in channel is called ship channel. It is basically a formed channel. Another option would be to check with a steel supplier and have them form channels from 10 ga. flat stock.
Welcome to the club. After a little more progress we'll teach you the secret handshake and give you your decoder ring. For my '30s era champ car I used a combination of 2 x 4 rectangular tube and flat plate sections for the rear kickup. I welded in weld nuts where I needed anchorage for shocks, exhaust, pumps, etc. I pie cut the front of the tube to pinch it down to 3" at the front crossmember, starting where the hairpins attach to the frame. I used a Ford 9" rear beacuse it is universally used with lots of aftermarket support. I doubt if it is appreciably heavier than weaker, less popular units. Mine has a QC grafted on for the look. Good luck with your project. Check out my nearly identical build below.
I would talk with Cornfield Customs, they're making custom framerails now, and he might be able to pre-bend a pair of rails for way less time/money than you'd spend making your own. Straight tubing always looks more out of place than ones with gentle curves.
Aluminium, TIG it and polish it! I have seen vintage racers with chrome frames, the polished alloy would look right at home and keep the race car light on it's feet.
I had some 1/8” mild steel bent into a channel. IIRC it was 1.5” x 3.5”, but they had trouble keeping it in spec as it was 12’ long which was max length for their press brake. I find it flimsy. Should look at the steel spec to make sure it’s what you need for strength. I was amazed when this kid built his frame from scratch. Some incredible fab skills. He graduated from engineering a few years back IIRC. https://youtube.com/playlist?list=PLAOSTFKtoB9maO-cBAZQCy5vT10cain0i&si=2ESdl8U0tL9jt7wX
Hey guys thanks for all the reply's and suggestions. A lot to consider. Been working on the dozer quite a bit since I started my post. I did pick up my front end. A 1937 Nash. Drop I beam, spindles, hubs tie rods, the works. 200.00 bucks. Got it at french lake auto parts in Mn. Hubs turn nicely on the spindles. I'll rebuild everything for sure. The 235 I have has the 848 head and high pressure oil system. Came out of a truck. Got the bell housing with it and a muncie tranny for 200.00 bucks. Got to get it on a stand and start tearing it down. Want to get the block fluxed and cooked. By the way the dozer takes up quite a bit of my time. It's right in side the door with a big double gantry I built I need to finish it and get it out of the shop to make room. Heading up to canada in a couple of weeks to pick up a winch for the machine. Been thinking about having the channel bent at the shop. Should give me some radius. 2 by 4 .125 or a little thicker and box in where I think it would need extra strength. Trying to eliminate trapped moisture inside a closed beam. WE have 20 acres on the Mississippi. A lot to keep up Things are budding and turning green. Sometimes I dont know what to do next! LOL. All I know is We just gotta keep moving. I'll check in later. Have a great weekend guys. Also need to learn how to post pictures. PS I have a model T frame front and back springs, crank perch rearend and front axel. Maybe we do some trading there is lots I'm gonna need. Thanks again for all your interest and suggestions. We never stop learning.
Hey flyer very nice job. I'll check out the build thread when I have more time. You did a nice job adding those rear horns to the frame. Back to the dozer today and then cleaning up trees, trimming and cleaning up river bank. Have a great weekend. Vintage Indy, Clyde
Thanks Clyde. As you peruse my build thread you'll note that In addition to making mine race ready I am also going to make it street legal, so I can have even more fun with it. Have you considered making yours street legal? Good luck with your dozer. If our paths ever cross I'd like to tell you about my buddy's Drott gas-over-diesel vintage dozer and how we got it started using a chain saw! as a starter motor LOL.
One thing I like to do when putting a sleeve in a tube to support a bolt is drill the holes big enough for the sleeve to go all the way through. Put the sleeve in the holes protruding slightly both sides and then weld in place. Then grind flush. Lil easier than trying to position inside a tube without windows plus when done the bolt torque won't be putting pressure on the actual frame rail. Plus if you ever remove the part you don't have to worry about the sleeve dropping
There was an Aluminum WOW 410 car t the Chili Bowl this year they had to reinforce the rea frame at the torsion bar mounts because it twisted it’s owned by Shane Carson out of OK city. It was so light the WOW circuit promptly declared it illegal and added a minimum weight rule. It was built by Don Nance.
the reality is your not going to be racing it so Id go heavier than lighter on the frame. easier to weld in stuff and no worries about strength then. Even on tubing I weld in sleaves especially on lighter stuff for mounting things . As stated above a make the lseave a bit long then grind / sand it flush . I chamfer the hole in the frame first then fell that with weld so when ground flat its strong .
Nice job on the repurposed frame. I like it. I have a T-frame but decided against using it. It needs a good home. Mine will be designed as a 2 seat, cramped a little but 2 seat. Back in the day during a period they did race with 2. I'll be that was as exciting as hell. frame is looking good. All the best in your project. Clyde
How so? There are vintage racing organizations all over the country for such cars. I believe two seaters were allowed up into the early '60s.
My query about frame material and design came a lot from reading quite a lot about a man named Gary, can't recall his last name, who seemed to have the funds and contacts to build a replica of a 31, 32 Studebaker Indy race car. His frame was channel and pressed I'm sure. very straight forward. Not sure of the particular scantlings, thickness for one. I just liked the way it looked. Our steel making capabilities today is certainly advance by 30's standard I believe. A lot today seem to like the 2 by 4 .125 rectangle tubing. certainly plenty strong enough. Using the through tubing, chamfered, welded and grind flush. Moisture held captive in the inside of the tubing doesn't seem to be an issue. I thought it would. Still haven't completely made up my mind. The local steel supplier I've been using will bend it for me as 1 option. or I can by the tubing. Still thinking about it. One can always box where extra strength is needed.? I do like your idea as quite a few have said. Thanks, Clyde
I probably wont race, but when somebody looks at my car I want them to imagine going around a dirt track at 60, 70, 80, 90 miles an hour plus, open wheels sometimes inches from each other. Remember sprint cars AKA (mud buckets) big spoilers, throwing mud and clay sometimes 50 60 ft. up into the stands. Took balls to race them dam things. And by the way age being a number as they say I'm closer to 80 than I am 70 I would be a complete disaster on a race track LOL. 1biggun didn't know that, but he was right never the less.
Gary Ash is active with the Antique Studebaker Club and has built a replica of a 1931/32 Studebaker race car. He has posted pictures on the Studebaker site, and I bet he can give you some great information about your project.
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