Well I finally have my touring down to the bare frame so now its time to get it back as straight as possible. As best as I can tell it is in pretty good shape, just tweaked bit.
The radiator mount holes are 1/4" spread to far apart. The frame rails sag 1/8" especially near the motor mounts and the entire frame is 5/16" out of square. I have been searching the forum for the proper way to straighten it. I was going to use the heavy yellow beam to push it back level with a jack but now I think heating it is the way to go so it will not sag in the future?
My question to you all is what order should I straighten the 3 areas in? I don't know if one will affect the other and cause me to over straighten something?
Thanks for your input.
I suggest you square up the frame and let the rest of it be. It likely was not perfect when it left the factory. If you heat the frame to the point that is likely to move, then all your change will be in the area that you heated. I think that's a good way to mess it up. I think you best do any straightening cold.
One of the members posted a good series of photos a few years back on how to heat and straighten a frame, I don't remember who. Maybe he will chime in and give you some good advice. KGB
I don't think heating is a good idea, the frame is vanadium steel, usually bending vanadium, medium to high carbon steel, would be bent cold, like doing a T con rod. If I remember rightly heating over about 800degrees starts to revert carbon steel back to a mild.
Frank, I think the trick was to heat and quinch without getting the metal red hot, this way the metal shrinks back to it's original shape with out applying any pressure. The skill is in knowing where and how much heat to use. KGB
I suggest that you leave it alone. You will never know the difference in the end.
I would not heat it, do the best you can with jacks and such. you will need to take it a bit beyond correct for it to return to it's original state.
Its pretty close already. If you can get any closer that will even better but as others have noted you wont know any difference once you get the car together.
There are more than a few T's running around with frames worse than that.
AS an engineer I prefer hot bending. A hot bent repair will leave the steel relaxed in the correct position. Cold bending will leave residual stresses in the steel and those stresses tend to make the steel more likely to return to the bent condition under load. In other words a cold bent frame will be weaker then a hot bent frame. See chart below. I hot bent my T frame and it is straight, the body fits well and is less likely to bend again.
I have never heard of a problem caused by heating a Model T frame. The frame is not tempered and heating should not hurt it.
The fellow who posted info on how to straighten frames a few years go was Brent Terry. I haven't seen him post for a while. He's more into Model A's now but has some nice T's as well. Here's his website: http://www.model-a-ford.com/index.shtml What Brent said, in a nutshell, was that if you bend the rails cold, they will want to fall back into their sagged state. Bending them back, then applying some heat to the stretched area, will cause the stretched part to shrink, thereby holding its shape better. As Keith said above, don't get it too hot.
Justin -- You are wise to want to straighten your frame as step #1 in building a car. It is imperative that you straighten and align your frame before putting the rest of the car on it. If you don't do that, nothing else will fit correctly. I would suggest doing it in this order: straighten the sagging frame rails first, then bend the front crossmember back into shape, then address the out-of-square issue.
There were instructions on how to bend the crossmember posted here some time ago. Basically, you set a floor jack on the middle of it, then wrap a chain under the crossmember and over the jack, then use the jack to push up on the chain. That will pull the ends of the crossmember closer together.
Justin, "Perfection" and "Model T" are two items that do not go together.
I would be surprised if Ford had frame and body parts as perfect as you are expecting.
I have a frame under a 24 coupe that was probably in an accident and it is bend to the point that the engine nose does not align with the the frame and also the radiator hose is way off. THAT FRAME needs straightening or replacement. (You do not need to measure to see the bends on this one)
I agree with Willie about T perfection.
They are not perfect automobiles and Ford didn't build them that way.
I found that out with the sheet metal that's on my 3 T's. Its definitely not perfect in its measurements and installation.
Its pretty close all right along with the frames, but perfect? No way.
We restore them and try to do the best we can and have fun along the way.
Thanks for the input. I agree that these cars were likely not "perfect" from the factory. At the same time I want to make mine as nice as I can without going totally nuts and redesigning everything. I think I will try the method of lightly heating it to get the frame to shrink back and do the repairs in the order that Mike suggested. While I may not notice any huge change, I am at the stage where it can't hurt to make it a bit better. I guess I am just totally geeked at how perfect some of the cars on this forum look and I donít want to cut any corners to hopefully get mine to look the same.
Jim did you quench with a wet rag or let it air cool when you straightened yours?
Justin, do as you feel you should, it is easy for others to tell you how not to fix your car. There is a lot of good information out there, As Walter Brennan used to say on the real McCoy's, I've had my say! KGB
The problem I'm having with his project is that the garage floor is way too clean & neat....I would be lost.....
Heating might work if you can heat the whole frame or the side your working on. You can't just spot heat it because the bend is not in one place. The bend is dispersed over a span and more of a bow. You'll cause the frame to cup then for sure it will be ruined.
I don't know if you could get the frame as hot as you need to, but you could do something like this: http://www.ar15.com/archive/topic.html?b=1&f=139&t=1109735
Wouldn't be very hard or expensive to make a nice, big, long burner that runs the length of the entire frame rail. You could bend the rail to the right place and then heat the whole thing at once. Probably the most amount of time would be getting the end cap with the holes drilled for air mixed right so that you had nice blue flames the length of the pipe.
While you have the frame there, Can you measure something for me? My frame is 102 inches from front of the front crossmember to the back of the back crossmember. That is 102 inches total length and i have difficulty installing parts. It is a ...well-used car and i think it might be stretched or something?
Justin asked, "Jim did you quench with a wet rag or let it air cool when you straightened yours?".
I just let it air cool.
If the steel was heat treatable, that I don't believe it is, quenching may cause hardened spots. For me it is safer to just let it air cool and any chance of changing the steel is reduced.
My frame was bent mostly at the body mounting points and heating a wedge at that point on the top of the frame, let cool, check and repeat if necessary, straightened it right up.
Ken -- My experience is that the frame rails ARE bent in one small area, and that is where the crankcase "ears" sit on it. It is not a gradual bend all along the rail. Of course, there are often other places where they're bent as well, depending upon each particular car's "experience."
You've probably done more than I have, Mike but I've never seen one bent at just the rear motor mounts. And that's usually not even the low point. If it was, it was probably in a wreck. They've all had a bow behind the mounts as well. Some even way back by the front running board bracket. (Wonder what causes that?)
I like what seth posted, kind of reminds me of the ring of fire to change locomotive wheels. I was also thinking about what ken says about a span bow but it seemed like it was bent mostly near the engine mount holes. I am going to do some really careful measuring tonight after dinner.
Kep yes mine is 102" as well before any adjustments, and I will measure after and let you know. Gentelmen thanks for the good thoughts yet again. I will post pics of my progress as I get it done.
A clarification, in order to correct a sagging frame heat should be applied in a wedge or V shape with the widest part on bottom of the frame. Kind of like this:
More info in straightening beams at:
1.The temperature of the steel does not exceed either (a) the lower critical temperature (the lowest temperature at which molecular changes occur), or (b) the temper limit for quenched and tempered steels.
2.The stresses produced by applied external forces do not exceed the yield stress of the steel in its heated condition.
3.Only the regions in the vicinity of the plastically deformed zones are heated.
I'm laughing at that mental picture of you laughing with coffee coming out of your nose!!
Yes, metallurgy is a science, not guess work.
Exactly. That's why I say don't heat it. Unless, of course, you're an engineer and have the equipment and measuring tools.
Thanks Jim that is exactly what I will do!
Didnt get much done tonight but did get the front rails back to 23". I will also heat them while braced so they stay put.
here is how i did mine
Even your chain looks too nice...
For real! Justin man do you grease or oil ANYthing? Lol, that shop is like a hospital.
straighten and tweak all u want, put it all together, drive it , go thru a dip, twist, or what ever, what do u have, a tweaked frame
Nice idea lorenzo. Wish I would have thought of that and I could of saved an hour at the milling machine. Yea Seth I oil stuff, but I sure do go thru a ton of paper towels and 409 for some reason! I might have garage OCD, I am thinking of checking into the Henry Ford clinic.....
Tonight I had a little time so I got it pulled back square. Cant believe that I got it within 1/16" ---very happy with that.
The fastback looks like its in the way of your T building. I have room for it if you need a place to keep it.... 7;^()