Welded rear axle?

[oldblueoval]

OK, so I know about welding spider gears but I recently read an article in Hot Rod magazine about an old "barn find" dragster and they referred to cutting and welding the axle shaft when narrowing the rear end. They said the fellow didn't want to spend the money for the local machine shop to tool up to cut and re-spline the axle so he cut and welded them himself. Don't want to sound too dumb but how is this done? Is it cut out the right amount, grind a taper on each and weld away, do you sleeve it then? Help me friends. As always, Thanks in Advance[

 

[Dr Crankenstein]

"Flirting With Disaster".

https://www.youtube.com/watch?v=0wxAMa3Prhk

I think he sectioned the axle and welded the splined section back on like you described. A sleeve would be good (space permitting) but still a horrible and dangerous way to shorten an axle shaft.

A friend once asked if I'd be willing to perform the same trick. He said it would be a low-powered "show" project. I told him I'd do it, but if it fails, you don't know me, my name, my ph# or address.

I suppose this sort of thing was common in decades past. I'm not old enough to know what they did back then, but I have seen some nasty failures due to "cheats" of this sort.

I'll be interested to hear other opinions on the subject... bob w?

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[Bamamav]

It was probably done a lot before a re-spline job became easier to get done. I'm with Dr C, I'd think a sleeve would be required to have maximum strength. One way to look at is, they weld the yokes on driveshafts, so whats the difference? It would probably be stronger than you think, but it might also be a weak spot.

 

[kenny c]

It will be a weak spot. I did what you described on a Mazda pickup rear end. It was for a trike with about 100 hp or less. and weighing 980 lbs. It has broken yet. The axle shaft on a Mazda is about 1-1/4 inches, way over kill for this application so I'm not scared. I have a friend that has done it to ford 9 inch for his modified garden tractor and has broken them.

 

[Sam_Fear]

I've wondered about this too. No way would I do it on a dragster, truck, or anything that put a huge amount of torque to the ground.

So what's gonna happen if it snaps?

 

[Bamamav]

So what's gonna happen if it snaps?

If it's on a axle that is retained at the flange by the bearings like a Ford 9", probably nothing, would be the same as any other broken axle. But if it was on a Ford 8.8 or GM 12 bolt where they use c clips to keep the axles in, unless it had the c clip eliminators you'd be watching your tire and axle stub passing you by....

 

[Old Iron]

If it's on a high power high traction vehicle, it'll send you to the ditch or worse, into oncoming traffic when under acceleration.

 

[Dr Crankenstein]

I broke an axle (side) gear once... the c-clip fell out and the axle tried to leave the scene. I was lucky. It broke when I dumped the clutch and the car was hardly moving. The axle slid out 10 maybe 12 inches, but it could have been different...

Five minutes before the failure, I was banging gears on our "main drag". If that gear had failed at the 2-3 or the 3-4 shift... there'd be flowers to mark the spot.

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[Neto]

I'm not an experienced welder at all, especially not this sort of thing, so I have a question, too. When a weld like this breaks, it will be at the edge of the heated area, correct? I busted one of the rear arms on a three-point tractor attachment when I didn't get the one-way out of the ground in time on a turn in hard dry ground. My Uncle got it welded back up, but it kept breaking at the edge of the heat. A guy from Argentina whose dad was a blacksmith told me that you have to heat the whole piece (or at least a fairly wide area?) in a forge, then weld it while it's cherry red. Anybody ever hear this, or try it?

 

[klink]

I'm not an experienced welder at all, especially not this sort of thing, so I have a question, too. When a weld like this breaks, it will be at the edge of the heated area, correct? I busted one of the rear arms on a three-point tractor attachment when I didn't get the one-way out of the ground in time on a turn in hard dry ground. My Uncle got it welded back up, but it kept breaking at the edge of the heat. A guy from Argentina whose dad was a blacksmith told me that you have to heat the whole piece (or at least a fairly wide area?) in a forge, then weld it while it's cherry red. Anybody ever hear this, or try it?

Any steel that has been heat treated will crack if it hasn't been annealed. The harder it is the faster it cracks... just as you described... right on the edge of the heat zone.

 

[Skip]

When I was just out of high school, my buddy twisted an axle in his 37 Chevy panel truck. We hunted all over for a replacement to no avail. His dad preped the axle and welded it back together. It was still in it (and working) when he traded it off for some other junk ride.

 

[BillM]

It was probably done a lot before a re-spline job became easier to get done. I'm with Dr C, I'd think a sleeve would be required to have maximum strength. One way to look at is, they weld the yokes on driveshafts, so whats the difference? It would probably be stronger than you think, but it might also be a weak spot.

The weld on the driveshaft doesn't see near the torque that an axle does - much larger diameter, and much higher RPM - hence a fraction of the torque.

 

[bob w]

Back in 1958 when I was building my first hot rod I put a 1948 Ford rear end in a Model A pickup. Had to have the torque tube and the driveshaft shortened. The enclosed driveshaft is about the same diameter as an axle shaft. The specialty shop I took it to cut and welded the solid shaft then sleeved it and welded the sleeve. This was in the day of stick welding. Worked fine in the light car with not much horsepower. I wouldn't do it in any modern application.

 

[oldblueoval]

Awesome response guys. I had to assume the weld and sleeve thing was about the only way it would work at all. The article talked about the rail being built out of pipe with a home made clutch can and an rear end out of an ambulance or something. Early hemi, log manifold and nitro. Wow! Thanks all.[