Mid PTO shaft ujoints out of sync, how far is too far?

[aczlan]

Working on getting a PTO shaft shortened for use on our BX2660 to run a front snowblower.
I took the PTO shaft down to a local shop and they shortened it and welded it back together. Unfortunately, the guy was in somewhat of a rush (understandable from talking with the owner the other day, they have worked 3 or 4 weeks straight without a day off and 70-100 hour work weeks), but the shaft is now welded together with the u-joints at the ends approximately 15 degrees out of time.
How big of a deal should that be on a 2000 RPM mid PTO shaft?
He said if it doesn't work to bring it back and they'll fix it, wondering if it's worth the wait, it took them two or three weeks to do this.





Thanks

Aaron Z

 

[ptsg]

Run it for short time to see it there is any weird vibration going on.

 

[aczlan]

Run it for short time to see it there is any weird vibration going on.

Turns out that welding it shrunk the ID of the end right under the weld and now the male side won't slide all the way in...
Tried cleaning it up with a file, but it still won't fit.

If I get bored tomorrow I may try again, but it seems pretty stuck.

Aaron Z

 

[ovrszd]

For the timing thing. I'd try it. It must run at a steep angle or it wouldn't have a CV joint on one end. But I'd still try it. I don't think you'll feel it running a blower. Might shorten the life of the joints a bit. I'd still try it.

For the slip, does it need to collapse all the way? Assemble and run it thru the motions to check?

 

[aczlan]

For the timing thing. I'd try it. It must run at a steep angle or it wouldn't have a CV joint on one end. But I'd still try it. I don't think you'll feel it running a blower. Might shorten the life of the joints a bit. I'd still try it.

For the slip, does it need to collapse all the way? Assemble and run it thru the motions to check?

Sorry, the picture is misleading. There are u-joints at both ends. There is not a whole lot of angle, but it needs to slip almost all the way in, at least 4" past where it goes now.

Aaron Z

 

[Warpspeed]

It depends on the angularity of the shaft. If the whole shaft is installed straight, or almost straight, the phasing of the U joints become far less critical.

With significant drive angularity at both ends, the shaft accelerates and slows down each ninety degrees, and with perfect U joint phasing this effect is supposed to cancel out at each end and you get smooth torque transmitted with minimal torsional speed fluctuations. Its difficult to say exactly where being unacceptable starts. The length and weight of the shaft, and the rpm come into it too, as well as what is being driven. All you can really do is run it, and make the judgement yourself.

 

[Stimw]

That is a TOTALLY a rookie mistake!
I have shortened about a dozen and that is the first thing you have to check.
You don't get that tired!
I would not trust it because even if it seems OK it will wear on some other parts.
They screwed it up, they should move you to the front of the line.
It is only a 1-2 hour repair.

 

[pmsmechanic]

I worked on a tandem truck once that had a drive shaft vibration. Turns out someone had installed the driveshaft one spline out of being in time. It was a lot less than what you are showing and there was an unacceptable amount of vibration. You can try the drive shaft but I wouldn't hold my breath.

 

[ovrszd]

Sorry Aaron, for some reason I thought I saw a CV.

I'd still try it.

 

[aczlan]

Sorry Aaron, for some reason I thought I saw a CV.
I'd still try it.

If I can get it filed out to fit, I may.

Aaron Z