First thanks for the help on narrowing my 12 bolt rear axle. It came out strong and straight. Now I need to fab a wishbone track locator to keep my rear end centered within the frame rails. The cheap one is .156 wall DOM that I can weld up with my MIG. The better one is chrome moly tube with 4130 tube inserts. My question is can I weld chrome moly with a Lincoln SP-135?

its been my experience that if your making 4130 welded then you weld with standard (es-70) rod if you are NOT heat treating after welding. If your heat treating I believe you use stainless rod (300series but thats a stretch on the old brain cells cause its been a few years) then heat treat.

and yes a mig can weld it.

Check out this it might help
http://www.lincolnelectric.com/knowledge/articles/content/chrome-moly.asp
http://www.eng-tips.com/search.cfm?action=Search&pid=0&requesttimeout=75

Be very carful welding 4140 ,after it cools the weld is very brittle .

WeCheat,
Nice link, the only thing I would add is preheat. It isn't mandatory but, Its always good to pre and post heat any steel with chrome.
Gary

Goofour, how bout a little info on your project as there are plenty of us car nuts at this forum. (not only the rear end but the car too)

I started with a 1976 Triunph Spitfire. So far it has a new 4x2x1/8 tube frame, 12 bolt rear end out of a 3/4 ton pickup narrowed to 32". 29x15x15 Houser drag radial rear tires, 16 gal fuel cell and two battery boxes that all fit neatly into that little trunk. After I finish the track locator I will be working on using S10 pickup spindles and disc brakes in the front. 350 ci small block and a four speed automatic plus a six point cage.
Its a lot of work but it should be a hell of a car when its finished.

I started with a 1976 Triunph Spitfire. So far it has a new 4x2x1/8 tube frame, 12 bolt rear end out of a 3/4 ton pickup narrowed to 32". 29x15x15 Houser drag radial rear tires, 16 gal fuel cell and two battery boxes that all fit neatly into that little trunk. After I finish the track locator I will be working on using S10 pickup spindles and disc brakes in the front. 350 ci small block and a four speed automatic plus a six point cage.
Its a lot of work but it should be a hell of a car when its finished.

Holy crap! That is one sexy beast!! You must post more pictures of that!!

Goofour: Great project, one mean car and nice work. Thanks for sharing.

I could swear I posted on this topic earlier - I guess I am loosing my mind....

Preheat, weld and then wrap with welding blankets to cool as slowly as possible - this is what I was taught.

Scott

Thanks guy's now I have a plan :cool: