Dragster frames........picture thread.

try again

 

Very neet riceman. Is that your car?

 

Yes it is my Cackle Car. I built the Fixture Jig in 6 hours. The bending of the tubes, the welding and the Doug Kruse built fuel tank were the only things I didn't do. The Hacksaw from Hell cut all the tubing. I fished mouth all the tubing with a belt sander and 1/2 round bastard file. I made all the 4130 brackets, linkage, brake lines, body and Motorplate. The 90% Nitro 354 Hemi is being built now. The Fueler is completely in a preassembly stage. The original Donovan aluminum bellhousing is on loan from Rich Guasco (Pure Hell Fuel Altered) which he ran in his Fuel Altered when he switched from the SBC to the 392 Hemi. The rearend was from Dan Horan's AA/FD, which was in the last front engine dragster that Don Long built. Thanks for looking

 

Does anyone know the tube OD of teh main rails on the Chassis Research LW 106 frames ?? was it 1 3/4 also what is the difference between 1020 tube and 4130 ?

 

1020 is low carbon steel. 4130 is chrome-moly. In general, the 4130 is twice the strength. For the same tube OD, you can run half the wall thickness with 4130, save half the weight but have the same strength. 4130 costs more.
Hope that helps.

 

cool thanks,,is it any different to weld than teh 1020 ?

 

1020 is low carbon steel, Iron alloyed with 0.2% carbon in solution.

4130 is medium alloy steel, Iron alloyed with ~0.3% carbon, ~0.95% chromium, ~0.5% manganese, ~0.2% molybdenum, ~0.25% silicon, less than 0.035% phosphorous, and less than 0.04% sulfur.

The biggest difference in the two materials is yield strength and how they heat treat.

1020 has a yield strength of 50,800 PSI, while 4130N (normalized) has a yield strength of 66,700 PSI (~31% greater than 1020).

Since it's a third stronger, you can use a third less mass overall to do the same job. Since it is also about 66% more durable (higher toughness), because of a ~25% elongation factor compared to 1020's 15% at rupture, structures built from 4130 tend to be more forgiving of over loading, in that they will bend and distort quite a lot before they come unglued.

You have to be careful when fabricating with 4130 though, as welded joints require more attention to detail, and proper technique (what exactly constitutes proper technique has been the subject of debate for decades now). If you don't cool the weld correctly, or normalize the entire structure after fabrication, you could harden the weld area, and all that elongation before the break goes away. Suddenly, instead of a very tough material that will lengthen 25% before tearing, you get a very hard joint that may not lengthen but 1%-2% before rupture.

4130 was developed in the late 1920's as airframe material for aircraft construction. It was meant to be gas welded together, and was formulated in such a way that the high residual heat from the weld would normalize the tube as it air cooled. It was self heat treating. BUT, now folks TIG it together, and the heat is far more concentrated, so the overall heat soak is much lower. Now the weld joints don't normalize as they cool, because it happens so much faster. TIG welded joints need some sort of after fabrication heat treatment to prevent cracking from over hardening.

THAT's what makes 4130 harder to work with. It's a great material when it's dealt with properly, but it can lead to hurt feelings and damaged people when it's not.

 

this might be the coolest thread ive seen on here

 

Hi i've got that exact chassis and body at our shop right now...thanks for that post now i know for sure its an spe car with hanna body!!!!!!!
Cool thread!~~~~

 

Good Thread this is my car: I built out of 4130 .065 wall .

 

great info and thread!

 

Great education from CoolHand....thank you!!

 

KIWI KEV= RULER

my right hands hurts from all the right click saving.

 

K went and got an order in today for tubing ,,going K-88 so 1/1/2 " tube .120 wall worried it may be a lil heavy but least it will be strong and they didn't have it in .095

 

Did you see me say anywhere in that post how the post weld heat treatment should be carried out? No, you didn't, because most folks are not properly equipped to do it, and I do not want to advocate any particular treatment, which may not always be the best choice.

Also, no offense to you or your friend, but if you actually read the old Army Air Corps Airframe Repair Manual (or even watch the film they produced as a primer), they instruct that large gas welded joints on material thicker than 0.036" wall should be reheated with a rosebud tip until the entire joint is red and then allowed to air cool. This was the field expedient approximation of a normalizing heat treat, and was obviously effective enough that they felt the need to teach it.

Do I advocate this practice? Nope, there are just too many variables for me to tell anyone how best to proceed. Nor do I honestly advocate anyone but certified chassis fabricators using 4130 tubing in car building. It is very easy to do it wrong, and there are a thousand opinions about what the "right" way to do it is, all of them different.

Not a lot of "Best Practices" writing has been done on fabricating racing chassis from 4130, 'cause honestly, not a lot of the metalworking industry is worried about it. This absence of reliable, sanctioned, and tested modern process publications makes it very difficult for even advanced fabricators to figure out how they should attack such a structure. The addition of third and fourth hand information, sometimes from people who were doing it wrong to start with, only serves to muddy the waters.

Home aircraft builders use very thin wall 4130 tubing for their airframes, and a great many of them gas weld it together the way is was designed to be used. Even though it is used and assembled in the manner it was designed for, every airframe must be inspected and certified before it can fly.

Unless you want to mandate that kind of rigorous inspection and certification process for home built cars (which I do not), I don't see a good (and safe) way for the average person to properly home build a 4130 chassis.

The old "they done it like this for years" head in the sand approach is what gets folks killed sometimes, especially if the information being related is third or fourth hand and/or incorrect to begin with.

Case in point: It is indeed very easy to botch the heat treatment of a welded joint outside a heat treating oven, if such is attempted. However, to suggest that an equally easy to botch welding operation is always better off if left alone (and thus possibly 3/4's hard) instead of being reheated red and air cooled (perhaps leaving the joint 1/4 hard, or just short of normalized), is a non-sequitur.

IMO, if you're going to the considerable expense of having a chassis made entirely from 4130, the cost of having the finished structure oven normalized shouldn't make your eyes bug out, and the process will guarantee a longer useful life for the chassis while in service (barring any sudden stops, of course ). Such ovens are fairly easy to find, and I know that certain circle track chassis MFG's do take the time to have their completed chassis oven normalized.

 

Materials cost bout this much now

 

What exactly is that kit supposed to build? $149 don't buy a lot of tubing, of any alloy.

Guess that Confidential Price list ain't real confidential anymore, is it?

 

Came with this,,finally after many years of waiting this highly sensitive information can now be declassified hehehehehe

 

lol

You might ought to have your sense of humor tuned up.

 

Bring reference material.

If there exists a currently certified process for GTAW joining 4130 tubing in racing chassis (with or without post welding heat treatment of the joints), I'd like to read a copy of it.

I have been looking for quite a while now, and have thus far been unable to find anything.

Again, no offense intended, but it doesn't really matter what one weldor says is right, regardless of how he is certified. What matters is if the certification institutions have issued an approved process for the application.

I've met and worked with guys who have decades of experience in their trade, and still do things improperly. Just because someone has been doing the same thing for 30 yrs doesn't necessarily mean they've been doing it right. That's what I meant by the head in the sand approach. The old "Been doin' it that way for 30 yrs, and nobody's died, must have been right." don't hold a lot of water in court unfortunately.

Regardless, I'd like to hear his process, in-depth if you're up for the typing, if for no other reason that my own education.

I'm an engineer, not a weldor, so while I know a fair bit about structural welding, certification, and inspection, I don't know it all by any stretch, and I don't have a lot of hands-on experience with airframe fabrication, so it'll be interesting to see how his first hand experience jives with what has been written about the subject.

That doesn't mean I can't weld though. I've developed a decent enough skill set that I can make solid and presentable welds with the SMAW, GMAW, GTAW, and OxyFuel processes in mild steel, and stainless with GTAW. I'm chipping away at the aluminum GTAW and OxyFuel processes, but I'm not to the point that I'd call them presentable yet.

Also, just an FYI, your friend has first hand experience, since he's the one who's done the work. He then told you about it, which means that you have second hand knowledge of the process. Just sayin . . . . . . . mostly to be a smartass.

EDIT:

I don't want you to assume that I'm saying that your friend is one of those guys that's been doing it wrong all his life.

I don't know him (or you for that matter) from Adam, so I can't say one way or another.

I'd just like to see some documentation showing a process that has been vetted by scientific testing.

Until we have a process that has been certified in that way (like pretty much all other structural welding processes), his way is just one of the thousand "right ways" that people have been arguing over forever.

That's what I was trying to get at. I don't advocate any particular process, 'cause I've not seen any of them that have been tested and certified sound.

All I wanted to do what impress upon people who may be unfamiliar with 4130 the fact that welding the stuff properly is not as easy or as cut and dried as welding 1018 is.

I was just trying to put that information out there.

If this discussion only saves one guy (who didn't know any better) from tyring to MIG weld a chassis together from 4130 and having the thing break in half on him, it's don't its job.

I just wanted to inject a "heads up" call for people who might be unfamiliar with how alloy effects weldability. Call it a "There be Monsters Here" buoy if you like.

 

And this is why I'm building my slug out of good old heavy mild steel.

 

Amen Kerry. When you get tired of chassis and parts certs, physicals, and nonsense, build a mild steel car, slow it down to 10's, and have fun. You get to weld it yourself, and 10's ain't much slower than 9's.

 

I'd be happy with 10s and no NHRA nazis.

 

Who said anything about 10's? ;-)

 

I thought some of this info from Lincoln Electric might help.

 

Well, there you go.

I have read that FAQ on Lincoln's website before, but I have never seen that last page where the process variables are laid out and which has been signed by an engineer (though were it adorned with a PE certification seal, I would feel a bit more reassured).

Looks like it was a process prepared especially for a single customer (which a bit of Google-Fu reveals is a small welding/fabrication shop in El Cajon CA).

How did you come across this document?

Good info regardless, I'm just curious.

 

Great thread....here's my contribution.....1968

 

Some of this information is the same as before, but it has some different info on the fill rod you can use. I got this info when I attended their Advanced Motorsports Welding Seminar at Lincoln Electric. I was working at Jerry Bickel Race Cars as a chassis fabricator and welder at the time. 200 MPH+ Pro Stock and 230 MPH+ Pro Modified chassis are welded with this process. Every chassis has to have a SFI 25.1E Certification.

The only thing I would change in the tungsten type. I would use 2% ceriated (orange stripe instead of a red stripe) tungsten instead of the 2% Thoriated tungsten. The point holds up better, it welds better, and its not radioactive.

Definately use a gas lens with a 7/16" cup. It makes a difference.

 

Excellent stuff!

Two out of nine posts hard core good technical information.

Keep that ratio up and you'll be one of the best assets to post on the HAMB in quite some time.

From Missouri to boot . . . . .

 

Weldworks, you have a pretty impressive background along with knowing your field inside and out.
I'm looking forward to seeing that fast back with the turbo GN stuffed under that long hood.