T frame question - is this a good idea or not?

I was thinking of taking one set of factory Model T frame rails and welding them together with a second set. That is, take a right side rail and weld it to the left side, and weld a left side rail to the right side rail, to create a boxed frame. I've eyeballed it, and it looks like they will mate perfectly together. Seems like this would be an easy and low buck (and using period parts, too) way to get a boxed frame. Seems to me it would be much stronger than the usual boxing method. Those rails don't weigh much, so it wouldn't add much weight. Thoughts? Reasons this wouldn't work? If I add a K-member, how much power do you think this could handle?

 

I wouldn't waist my time with the old T frames... Buy some 2x3 or 2x4 square tubing and build your own frame, It'll be stronger and more reliable. Those old T frames were made to twist and flex more than the model a frame. If you really want to be period correct get an Model A frame and box it. it'll look better. You can go as far as you wanted trying to be period correct, but you have to think about safety and reliability if you plan on driving it.

 

If you have a second set, tack them together and post pics.

 

Thanks for the input. I know that these are the common answers regarding using a T frame. However, I can't see how a relatively small guage square tubing frame can be stronger than this. This would basically make a 2(h)x4(w) tube with 3/8 inch walls. What am I missing?

The way I fiqure it, most of the remaining twist would be handled by a K or X member.

 

I don't think that I have the second set. I think that I'm down to my last frame that doesn't already have a body bolted to it. I should be able to get another T frame locally and cheap, though, if there's any chance that this will work.

 

2 h, 4 w, 3/8 wall??? Try 1 1/2 wide, 3 tall .120 wall, or 11 gauge. For a T sized car, that is the standard. I had one like that with a J 2 Olds, it would lift one wheel easy, drove it for years with no sign of frame weakness. Look at the adds in the car magazines, blow up a picture, and make one like it. Its not as hard as it sounds, you will have a better frame, and it will make a safer car to be in.
Good luck!!

 

It will work.
It's "traditional" as in, been done "back in the day".
You can still claim it's a real antique Model T Ford and not a "Kit Car".

Better and stiffer would be weld up an 8 point rollcage on the single frame.

Better still would be a fully triangulated space frame, ala, "Birdcage" Maseratti or Mercedes 300SL.

 

I guess I'm just not getting it. How can a 1.5x3 .120 wall frame be stronger than a 4x2 .37 wall frame?

 

Thanks for that info. I thought that it must have been done before (successfully or unsuccessfully) but couldn't find any examples of it.

 

Try to bend a 2x4 piece of wood on it's side, then try the other way... laid flat it's much weeker than on it's side. You can get thick walled 2x3 square tubing and it won't flex... even try laying it on the floor with a small piece of wood under one end see which way flexes the most... then you'll see what I mean.

Just cause it's been done doesn't mean it's safe and reliable... I've seen a lot of gaunchy crap that was done... ended up failing in the end.

 

OK, now I see what you mean. Good example. But, safety of the frame is related to how much horsepower is being put through it, and is part of my question...what would the safe horsepower limit be of this? I think that the stock T frame is good for almost 100 horsepower from a banger. Would this be twice as strong...taking almost 200 horsepower? That would be the most that I would be putting to this frame.

 

I personally wouldn't be worried about that... it's the up and down motions of the car and the weight you'll put on it... seem like to me it might fold up on you, with todays roads. It may be alright if you're just going to run around town. but I wouldn't take it out on the high, might hit a pot hole and fold that sucker up around you... wouldn't be a fun ride!

You'll have to address the front crossmember if you are going to lower it any also....

 

You mention 200 HP, and period parts.
What are you getting 200HP out of?
Is it also a high torque engine or is it getting the inflated relative to work done HP figure the Japanese way, with high RPM and light internal parts?
How are you mounting it in the frame?

The Model T had side mounts at the flywheel area and the frame was designed to twist some on purpose so it wouldn't tear itself up too soon on the not yet paved roads of America.
If you use front side mounts to add 5 times as much Torque as the stock car had it's going to twist a ladder frame no matter what you use for rails.
It'll need an X or K member to help there, or one of the resolutions I already mentioned.

 

Folding up the frame is not a realistic concern with even a stock T frame. T frames bend, not break, due to the nature of the spring steel that they are made of. They will take an EXTREME amount of bend, and still spring back into place. Might be a concern with a very heavy engine like a J2, but the heaviest engine choice I have for this RPU is a 1963 289 Ford. May use a banger, though. I know guys with stock framed speedsters that drive them daily at 75 mph on the freeway.

No need to have to do anything with the front crossmember. A T can be lowered 3 or 4 inches with a lowering spring. Or, dropped T axles of up to 7 inches drop are available. Or, Laurel drop brackets can be used.

 

My engine choices for this RPU:

1963 289 w/C4 (200 horsepower)

Mod'ed T engine (maybe 75 horsepower)

Mod'ed 1927 Chevy 4 (about 100 horsepower)

1952 Ford flathead (about 150 horsepower)

I don't think that a modified frame would be necessary with either of the 4's. But, it would be with either the flattie or 289.

I haven't really got my head around this build, yet...one of the reasons that I'm asking these questions.

 

[They are not made out of SPRING steel.

 

Looks to me like you already had your mind made up before you asked for input.

 

"Vanadium spring steel"

 

No, not at all. But I do want an explanation for an opinion...enough of an explanation to think through the opinion.

 

There are tons of ladder type frames going down the road under various rods. If you gusset the frame it will be fine.

 

Consider using a TT truck frame. They're much beefier than the car frames, not much different from the A frames if I remember correctly. Just cut the rear down to get the wheelbase you want. One of the HAMBer's from the UK is using one on his roadster build, sorry I can't recall his name.

 

That's a very good suggestion. I had considered this for another project, in the past. It deserves consideration for this project.

 

T-Time, here's a thread from 2005 with pics of the TT frame under a modified, also some good discussion about doubling T frames:

http://www.jalopyjournal.com/forum/showthread.php?t=80491


.

 

That T-Frame is low Carbon Steel, thats real old.
It's not going to like a lot of heat.
Also that frame was designed to flex, boxing it too much will add undo stresses.

Just some thoughts

 

Thank you! I knew that doubling the frame could not be a new idea. It is just too obvious. Seems like it would be plenty strong from what is said in that thread. I still like the TT frame idea better, though. I think that I will be going that route when the time comes.

 

It was not considered low carbon steel, at the time. Maybe it is today???? The T frame used Type L steel with this composition: .23-.30 carbon, .35-.50 manganese, .04 maximum of phosphorous, and .05 maximum of sulfer. Low carbon steel was .05-.15 carbon.

 

If you are still considering the T frame route - why not use the 2nd frame rails - cut each one down the middle (lengthways), fit them INSIDE the outer rails, mark a cut line and take enough out to give you plenty of weld penetration, if you like you can cut or grind the thickness of the rails off the inner sets edge, so they fit flush inside then weld up fully. This way you have a boxed set of rails with plenty of extra strength which would look better than two just welded side by side. It's worth a mention anyway

cheers

Bob

 

Sound like good idea, but maybe too much work for the end product?

 

I've seen a stock T frame break at the firewall. not pretty, not springy either. I wouldn't use one as a go-kart frame. Just my $.02

 

Well, all I can say is that your experience is counter to mine. I've been around T's all my life and my experience is that T frames flex like crazy and spring back into position. I never seen one that has broken. In fact Ford used to send out front axles (also made of Vanadium steel) to its dealers that were tied in knots to display the flexibility of this type steel.

From a Ford sales brochure: "Nobody disputes that Vanadium steel is the finest automobile steel obtainable. Ask any disinterested steel expert about Vanadium steel and listen to him enthuse about its dynamic strength and power to withstand sudden shocks, torsional strain and vibration; its tensile strength, elasticity, ductility and withal the ease with which it stands machining. We defy any man to break a Ford Vanadium steel shaft or spring or axle with any test less than 50% more rigid than would be required to put any other steel in the junk pile, and that's a conservative statement."

I've attached a picture of a T crank, made of Vanadium steel, that has been bent by a steam hammer. Ford claims that it was later straightened and still showed no sign of fracture.

They also constructed a T spring of "regulation spring steel" and it bent and took a set at 675 pounds of pressure in a compression test machine. They then test the T spring made of Vanadium spring steel to 3100 lbs, with NO set!

Vanadium steel may bend, but it does not typically break.