Welding a PTO stub to a larger shaft?

[aczlan]

So, I was snowblowing the other day and my 1.5" keyed shaft to 6 spline PTO shaft adapter split right on the groove for the key. Instead of spending $46 (with shipping) for a new one from Surplus Center, would there be a downside to just welding the stub to the shaft?
The adapter used to look like this:

Surplus Center link: 1-1/2" Keyed x 1-3/8" 6T Spline F/M PTO Adapter | 1 Piece Solid Couplers | Shaft Couplers | Power Transmission | www.surpluscenter.com

Now, it looks more like this:






The shaft it connects to looks like this:


Would I be better off clamping it back "closed", then welding it together, or cutting the stub off of the adapter, then welding it to the shaft?
When it was all together it used to look like this:
View attachment 536500

I have a torch, a old Lincoln AC only buzz box, and a bunch of 6011 in various sizes. I can also bug the neighbor and use his Miller 252, but he only has it setup on 120VAC, so its limited on how much power it can put out without tripping the breaker.

Aaron Z

 

[George2615]

If you weld it to the shaft would you still be able to change that carrier bearing if you needed to in the future.
I'd replace it with new and maybe drill, tap, and add a second set screw to secure to the shaft if there is only one now.

 

[Gary Fowler]

Get the right adapter with keyway and double set screws and it may hold better.
It is going to be next to impossible to keep the shafts aligned when attempting to weld them together so I don't think I would try that with the equipment that you have.

You may keep them aligned if you start with a perfectly fit up keyway shaft adapter and then weld it to the shaft around the end circumference for extra strength

 

[dragoneggs]

I think you limit your future repair options without a major hassle if you weld it to the shaft.

 

[zzvyb6]

Why not get a U-joint yoke that fits onto the keyed shaft and mate it with its partner on the pto shaft. Looks like you were going pto to pto, so go pto to keyed shaft. That's what I did for my blower. My pto drive was a 15 spline to keyed shaft.

 

[aczlan]

Why not get a U-joint yoke that fits onto the keyed shaft and mate it with its partner on the pto shaft. Looks like you were going pto to pto, so go pto to keyed shaft. That's what I did for my blower. My pto drive was a 15 spline to keyed shaft.

That is what I had before, there are two reasons I'm going this route.
1. This way it's a 5 minute process to remove the snow blower versus 20 minutes just on the U-joint
2. I'm looking at putting the bush hog on the front at some point to go and work in some of our hedgerows and that way I can just hook the Bush Hog on.

Aaron Z

 

[aczlan]

I think you limit your future repair options without a major hassle if you weld it to the shaft.

I would remove the part that currently goes around the outside of the shaft so it's just the stub shaft being welded to the shaft on the tractor side. If that works the way I think it will, I would still be able to remove the front carrier bearing over the stub shaft.

If you weld it to the shaft would you still be able to change that carrier bearing if you needed to in the future.
I'd replace it with new and maybe drill, tap, and add a second set screw to secure to the shaft if there is only one now.

Being able to replace the carrier bearing would be important. I would just be welding the stub on to the end of the shaft so the carrier bearing should still fit over the stub. I hadn't thought about a second set screw I just ran a bolt through the whole thing but that may be a good idea.

Get the right adapter with keyway and double set screws and it may hold better.
It is going to be next to impossible to keep the shafts aligned when attempting to weld them together so I don't think I would try that with the equipment that you have.

You may keep them aligned if you start with a perfectly fit up keyway shaft adapter and then weld it to the shaft around the end circumference for extra strength

That is the right adapter as near as I can tell. It's an inch and a half keyed shaft, it had a set screw in it (which apparently fell out) and a bolt through the whole thing (which sheared when everything came apart).
Keeping the shafts aligned would be somewhat difficult but they do both have machined flat faces and my thought was to find a piece of pipe that would just fit over the splines of the PTO shaft, that should have an OD of about an inch and a half so I should be able to clamp straight across for at least the initial welds to get it in place.

Aaron Z

 

[Tractor Seabee]

How long did the original part hold up? A new a part may be worth it in the long haul. Trying to keep something like that aligned and not heat warped would be tricky for our kind of shops. Having an out of line badly balanced part may accelerate the next failure. Looks like the shaft needs some TLC also. Might be smart to replace the shaft and bearings if this is a high hour machine, forestall the next failure. The stress created by that failure may have telegraphed into that pillow block bearing. It does not appear to be very heavy duty type. Due to similar past failures the OEM may have a new replacement part that is re-designed and more durable. Worth checking out.

Ron

 

[dragoneggs]

How long did the original part hold up? A new a part may be worth it in the long haul. Trying to keep something like that aligned and not heat warped would be tricky for our kind of shops. Having an out of line badly balanced part may accelerate the next failure. Looks like the shaft needs some TLC also. Might be smart to replace the shaft and bearings if this is a high hour machine, forestall the next failure. The stress created by that failure may have telegraphed into that pillow block bearing. It does not appear to be very heavy duty type. Due to similar past failures the OEM may have a new replacement part that is re-designed and more durable. Worth checking out.

Ron

I tend to side with Ron here. If it were me, I would buy the replacement part if it was for a tool I plan to get a lot more use out of.

 

[aczlan]

I don't know how long the original keyed shaft on the U-joint lasted,.
As I understand it, the tractor it was originally installed on was a 1996 60 horse New Holland that was owned by a local municipality. They sold it at auction and the guy who bought it wanted to run a bush hog on the back but had no interest in the snow blower. I bought it from him and I have little to no idea of the history of the snow blower beyond that.
With the adapter on the tractor end of the shaft and a female PTO connection on the U-joint, it's now on a 38 engine horsepower Kubota so the shaft itself is plenty strong enough. I think that the set screw walked itself out (because it was missing) and that let things wobble enough that it tore apart.
I was debating seeing if I could find a larger piece of pipe that would just fit over the outside of the female keyed shaft receptacle and prevent it from splitting like this again, but I am of the opinion that if I could keep the set screw tight enough, failure won't reoccur.

Aaron Z