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Welding a driveshaft yoke.

Stellrammer

Well-Known Member

Stellrammer

Member​

I’ve had to replace the centering yoke attaching to a cardan joint. The previous runout on this and the corresponding counter weights was considerable. I have the replacement part in place and running within .002”( phased to within half a degree)
I’m not competent enough to weld it, should I tack it and send it out ? Is it better to weld it between centers to avoid shifting , is tacking it before sending it out going to cause problems ?

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Proxule

Ultra Member
If you do decide to weld, What ever you do, Do not ground you lathe, Ground your shaft or as close to your weld as possible. Logic being is you might arc your ball bearings or cylindrical roller / taper roller bearings in the headstock.

You will get 1000 different approaches from the members on this forum, In the end do what makes you feel comfortable.

Gluck!
 

Stellrammer

Well-Known Member
If you do decide to weld, What ever you do, Do not ground you lathe, Ground your shaft or as close to your weld as possible. Logic being is you might arc your ball bearings or cylindrical roller / taper roller bearings in the headstock.

You will get 1000 different approaches from the members on this forum, In the end do what makes you feel comfortable.

Gluck!
What would make me comfortable would be the mating parts not shifting out of alignment from heat, maybe I’m being unnecessarily cautious about it moving.
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
Do not ground you lathe, Ground your shaft or as close to your weld as possible. Logic being is you might arc your ball bearings or cylindrical roller / taper roller bearings in the headstock.

@Stellrammer - I'd also turn off and unplug your lathe so there are no ground paths.

I'd do a set of tiny tacks if I were you. But if you are worried about it moving, I might epoxy it in place in four locations for now and let the weld shop remove the epoxy after tacking it between the 4 epoxied spots.
 

phaxtris

(Ryan)
Premium Member
Premium Member
I have shortened several driveshafts, never on a lathe, just zip cut and a wrap around, no vibration issues, but you can always send it out to get balanced after the fact

4 solid tacks, and weld, I've always welded them in 4 quadrants (before lathe, no positioner) weld one quadrant then the opposite quadrant and don't take a break in between

You are lucky that is a pretty short shaft, the shorter the less inclined they are to vibrate

If you are doing it on the lathe, like everyone has stated, do not ground the lathe

It's not as scary as you may think, even if you can do a half way good MIG bead you'll be fine...driveshaft guys aren't exactly pro's (I bought a shaft once....what a waste of money)
 

Chicken lights

Forum Pony Express Driver
I’ll be the odd man out, I don’t mind. I would recommend sending it out to a driveshaft shop, it’s what they do day in day out they should do a good job

If it’s double cardan it’s likely a front axle driveshaft- the old rule of thumb was front axle was 4x4 only, not likely for high speeds or constant use, so home shop welding was fine, as it didn’t see highway use

So I would say weigh how much it will get used, at what speeds, and how much you need to trust it
 

trevj

Ultra Member
I'm happy enough sticking a PTO shaft for a tractor implement together, but those don't turn all that fast (1000 RPM max, 540, for most of my stuff).

You are gonna have to send it out to a driveline shop to get it balanced anyways, yeah? So tell them what you need it at, as far as dimensions, and get on with fixing something else! :)
 

trevj

Ultra Member
“Most” driveshafts don’t need to be balanced. Is it a good idea? Sure, but it’s extra money, too
Like you said in your post earlier, usage is going to be a factor.

If the OP is not confident in welding it straight, as stated, then it's a no-brainer for me, to say it goes to the shop. If it merits the balancing, and the OP states, if I understood him correctly, that it was pretty loaded up with weight to get it balanced before the works commenced, then it probably would not be a bad idea. Fewer guys around with a balance rig, but if anyone doe have it, the driveline place would be it.
 

Stellrammer

Well-Known Member
My skills as a welder are not up to this task, it is definitely going out to be welded.
It is pressed in pretty tight and needed a BFH to persuade the replaced centering yoke to clock true. My only concern is that alignment being influenced by heat or some undue knocking about. Welding and its effects on steel is not in my wheel house.
Judging by the welds from the factory on the 1969 frame, and the haphazard assembly of the drives shafts I’m beginning to think the Ford Truck Assembly plant in Wayne Michigan suffered the same issue.
 

terry_g

Ultra Member
If you tack weld it in three places and then put it back in the lathe and check the run-out.
If its changed you can adjust it by peening the tack welds. Once your happy that it is close
enough weld it. If it vibrates it might need to come back out and be balanced.
I had a 87 mustang that had a slight vibration that started at 90 Kmh and stopped at 105 Kmh.
By putting a hose clamp on the drive shaft and moving it around and from one end to the other
between test drives I was able to eliminate the vibration.
 

Darren

Ultra Member
Premium Member
You can weld it on the lathe, no problem. you'll need a grounding arrangement. After welding, it will be bent. a torch and a cold wet rag will take care of it. If you aren't comfortable doing that, it's probably best to send it out for welding, straightening and balancing.
 

CWret

Ultra Member
Premium Member
When welding on my motorcycle - I put the ground as close as possible to the weld. I also disconnected the battery, unplugged the CPU, and pulled the fuses (dirt bike only a couple of fuses).
So I suggest you unplug the lathe and pull any fuses it might have.
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
So I suggest you unplug the lathe and pull any fuses it might have.

That was my advice earlier too. But it got lost in the length of the thread.

It isn't enough to put the welder ground close to the work. Anyone who has ever looked at what a welder does to the supply line voltages would quickly realize that it isn't just the weld current that is a problem. So are all those spikes on the supply lines. Best to totally remove all possible ground and supply line noise by Disconnecting the machine. Removing the fuses is a good idea too. It's not really that damage is inevitable. But why take silly chances.

It's funny. With all my automotive design experience you would think I would have dealt with drive shafts before. But I haven't. I've only ever had to specify what I wanted and then deal with poor quality suppliers. Finding problems after the fact is always a lot easier than making sure they don't happen in the first place.

I think @Stellrammer is right to just let someone else handle it. Especially since his welding skills are probably a lot like mine. Then he doesn't need to worry about damaging his lathe.
 

WilliamR

Active Member
I've always had driveshafts done at shops. A friend shortened his, shimmed it with beer cans and welded with 120V mig while I turned shaft. Didn't stand a chance or so I thought. Never had a problem with it. No vibration or sign of failure. Large V8 in small Rambler.
 

Tom O

Ultra Member
I’d still put on one of those driveshaft loops on it just to make sure, when I needed a different driveshaft I’d go to the wreckers with a tape measure. My 58 Chevy use to eat the stock 3 speed tranny’s and one time at the wreckers they wanted way to much for them so I told them I’d go down the street later that night I went back and carried out two one in each hand.
 

phaxtris

(Ryan)
Premium Member
Premium Member
it came out fine, I did tack it, had a pro weld it, checked runout, no movement. After everything gets shaken down with the drivetrain running while on blocks, both front and rear drive shafts are going out for balancing.
1976 BroncoView attachment 33295View attachment 33296

Yea I wouldn't worry, I was more refering to the comment about the driveshaft loop

Looks pretty clean, at least until that first mudhole :D what tires are going on this thing in the end ?
 
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