welding axel tube to pumpkin

[pitjeep]

i want to weld the axel tubes to the pumpkin . the tubes are steel & pumpkin is cast thought id put a few 1in incerment welds around each side. can i mig this or should i stick it? what wire is recomended

Thanks

Rob

[tigman]

All the rear diffs I have ever seen were plug welded.

I would not weld the tube where it enters the centre section as it will eventually break.

[Sparkeee24]

Howdy Howdy! A little more info would be great here I have a Scout II, with welded knuckles. I would tend to want to grind/alter those rather then the pumkin. Alot of pumpkins are cast iron, not cast steel. Knuckles are acst stel or forged steel. the reason is for shock loading. the pumpkin does not suffer the same shock loads as the knuckles do. They could be cast as well, but mine actualy look forged. These will take tons of heat input. I would never attemp this with anything less then 180 amp+ machine. An industrial machine would be recomended. I would highly recomend using stick method for this. Also, what i did was put 2 seperate pairs of non-castering bracketed wheels upside down on plates. Then tacked these to the tops of a pair of jackstands. I tacked the knuckles to the tube in 5 places, little tacks. then used good 7018 rod all around, built up. I rotated the axle assembly easily on these rollers while welding. i cut and turned my knuckles to give my scout both caster, and a pinion pointed up for A cv shaft. I really don't feel that comfortable with a person performing this, unless we have more info to go on. feel free to elaborate for us, many interested folks here! as allways, it is not recomended to drive any altered vehicle on our nations roads without first being approved for safety bye the local DOT. Brian Lee Sparkeee27

[pitjeep]

its a amc model 20 ill have to look again but i swear one of my parts rears has the tubes welded to the housing as well as the plug welds mentioned earlier.

[Spook2]

i want to weld the axel tubes to the pumpkin . the tubes are steel & pumpkin is cast thought id put a few 1in incerment welds around each side. can i mig this or should i stick it? what wire is recomended

Thanks

Rob

Opinions on the "proper" way and material to use would probably fill volumes. I just grabbed some 7018 because it was handy. It's been there for about 3 years now and not showing any signs of cracking/failing. I haven't exactly babied it. What kind of ride do you have?

Here's my junk.

[Pin Head]

All the rear diffs I have ever seen were plug welded.

I would not weld the tube where it enters the centre section as it will eventually break.

X2

The tubes are pressed in and then plug welded. It is often hard to drill out the old plug welds because of carbide precipitation in the fusion zone. Welding around the oustide tends to crack.

[Sparkeee24]

Howdy howdy! I noticed you said parts rear. Alot can go on between the time that axle was produced, and the time it entered your hands. Plug welds would traditionally be factory. What is the reason for welding pumpkin to the axle tubes? The last post about carbide presipitation is very accurate, as well as the fact that they are press fit and shrunk on around the tubes. the thought behind a big plug weld, is that even if the weld breaks between the axle tube and the diff housing,(where it is most likely due to dissimilar metals.) you still physically have the plug securely welded to the tube underneath, which is good weldable steel. Basically, not a catastrophic failure if / when it does break from fatigue. I would try and leave the cast iron alone, but if you had too, then use the high nickel rods, with lots of preheat and postheat. The 7018 recomendation earlier was for knuckles to axle tubes on fronts. Brian Lee Sparkeee27

[pitjeep]

heres my 79 building a 77

[PJinNJ]

If you're concerned about the tubes separating from the pumpkin there are many companies that make braces than span the pumkin and lock onto the tubes for many reasons but they all will keep the tubes from pulling out if that is your concern, Poison Spider is one that comes to mind.

[Aeroweld]

In the 70's I did a few Dana 60 style rear ends for drag racing applications. It was common back then to weld the tubes to the center section. I didn't have access to MIG at the time so I stick welded them with a 5/32dia. 7018. "I" would still prefer SMAW to MIG today.

My $.02, Mileage and results will vary

[pitjeep]

so can i plug weld it without dismantleing it if i weld alittle let it cool weld somemore?

[Bowtieman31]

so can i plug weld it without dismantleing it if i weld alittle let it cool weld somemore?

Not even a good idea.
The arc has the possibility and ability to jump any gap inside that gear case. That means you have the very real possibility of ruining any of the bearings inside. Not to mention starting a fire in the gear oil or at least producing heavy smoke inside the housing.
Tear down the rear assembly, clean the case with a good solvent/degreaser, wash it out with hot soap and water, rinse good and then weld it.
The extra work will be worth it in the long run. Believe me, been there AND done that about 25 years ago. It does leave a lasting impression ya know?

[djb]

i want to weld the axel tubes to the pumpkin

Tear it down and clean it out...I've spent many many hours(and weekends) tearing down machinery just because of errant grease and oil, for 15 minutes of welding.

Yes you can weld cast to steel. Off-the-shelf lincoln .035 hard wire with shielding gas; preferably a welder that can muster more than 150 amps.

I would suggest warming the fit-up slightly with a soft flame before laying the welds. Just in case, I thought I'd add "tack really good in 3 or 4 points before making your stitches"

Let assembly cool down a good minute before each weld, so you aren't running red hot and getting different penetrations and weld bead sizes, as well as warpage.

my 2 cents. bring back the change.

[Sparkeee24]

Howdy Howdy! So! Out of curiosity.... why? Why are we attempting to do this? Dana 20's are week, yes. I really like the recomendation made earlier, about purchasing a brace that goes underneath, or over the axle tube as an external brace. IF this is the concern. Why not put a lockright in at the same time you tear apart the rear end? Or you can Lincoln lock it, Though I wouldn't unless it's strictly a trail rig. I personally, have considered, and still may, build a brace for the external installation of a brace onto the axle tubes, that goes across the pumpkin to keep huge airtime hits from snapping my lil dana 44. My scout weighs far more then any j^%p. If you think about it, structurally, installing an external brace is far far stronger, then simply adding material between the axle tubes and the pumpkin, if that is your concern. If your shortening or rotating the axle tubes, then thats another issue anyway. I Really like the idea, of making spring perches, that weld directly to the axle tube, and build the bracing as a sub assembly to fit above the axle tube. Mine will be two tubes, probably 2" X 3" and 3/16" thick. on one end, cut to the mating angle to fit on the side on the spring perches, and the other side cut at a steep angle, to MORE closely fit above the pumpkin, but to the side somewhat. Then I would use a 3" bye 3/8" "strap" across the top of the pumpkin, curved to the rough shape of the top of the pumpkin. Then in two places Near the pumpkin sides, about 1/2" away, I would weld a vertical supporton each side. These would be made of the same 3" 3/8" plate, set 90 deg to the axle tube. on one end, cut to the shape of the axle tube, on the other end, a 90 deg cut to match the underside of the square tubing. The primay reason for welding as a sub assembly, is to makes it all easier to weld to the axle tubes once these other structural welds are complete. So, anyway, thats my plan. It should be significantly stronger, without too much added unsprung weight, and without reducing any ground clearance. I know, it wouldn't be as strong ,as putting the whole assembly on the underside, but say, 20-30% stronger is probably all I would nead with 33's, and my flat gravel lead foot / rock and root slow and steady approach. P.S. I'm not trying to hi-jack your thread. It's just sooo interesting the backyard engineering we all do! Brian Lee Sparkeee27

[Pin Head]

This would be a good time to dump the D20 and get a D44 or D60. People successfully weld on axle tubes all the time without disassembly. Put the work lead on the tube to make sure that the ground path does not include your bearings. Electricity will always take the easy way to ground.