Welding a PTO stub to a larger shaft?

[dragoneggs]

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

I think your failure analysis is mostly likely. Buy a new part... put a little blue loctite (good thing I spell checked as it corrected to 'lactate') on the set screw and get back to blowing.

 

[BrokenTrack]

You don't even have to buy Locktite, fingernail polish is the same thing. Put finger nail polish on the threads of the set screw and you will be set. I do that on the PTO shaft of my bulldozer, converting it from 21 to 6 spline.

 

[dragoneggs]

You don't even have to buy Locktite, fingernail polish is the same thing. Put finger nail polish on the threads of the set screw and you will be set. I do that on the PTO shaft of my bulldozer, converting it from 21 to 6 spline.

With all due respect... No, it is not the same thing. And not disputing whether your favorite polish is effective... but it is typically a blend, primarily Ethyl Acetate (more a solvent) whereas the Blue Loctite base is Methacrylate Ester, which has better long term adhesion characteristics. I'm splittin' hairs here for this application but nail polish is not as good a thread lock as Loctite.

 

[BrokenTrack]

With all due respect... No, it is not the same thing. And not disputing whether your favorite polish is effective... but it is typically a blend, primarily Ethyl Acetate (more a solvent) whereas the Blue Loctite base is Methacrylate Ester, which has better long term adhesion characteristics. I'm splittin' hairs here for this application but nail polish is not as good a thread lock as Loctite.

In my experience I have never had a bolt applied with finger nail polish rattle out though, and this includes using it on my bulldozers, skidders and excavators.

I got a wife and (4) daughters so I have PLENTY of fingernail polish kicking around, and even for those that are bachelors, fingernail polish at the dollar store can be had for a buck. True Locktite might be better, but it if finger nail polish still works, why spend the money for something that is not warranted?

 

[CADplans]

If that were mine,,,
I would pound the adapter back to the original shape.
then I would find a piece of pipe that would fit over it,, and weld the pipe to the adapter.
(Make sure the new pipe that is to be added does not hit the bearing or bracket)

If there is a bolt used to hold the pto adapter to the shaft, drill the hole as necessary in the pipe.

If the adapter was held by a set screw, I would change to a 5/16" through bolt.
drilling the shaft will be easy, if you have a couple new drill bits.

Slide the pipe added adapter on the shaft, tighten the Grade-8 5/16" through bolt,,,
and go blow some more snow,,,, :cool2:

Even if I were to get a new adapter from Surplus Center,,,
I would add a piece of welded pipe before the initial use.
That adapter is too lightly constructed for this application,,, IMHO,,, :thumbsup:

 

[aczlan]

If that were mine,,,
I would pound the adapter back to the original shape.
then I would find a piece of pipe that would fit over it,, and weld the pipe to the adapter.
(Make sure the new pipe that is to be added does not hit the bearing or bracket)

If there is a bolt used to hold the pto adapter to the shaft, drill the hole as necessary in the pipe.

If the adapter was held by a set screw, I would change to a 5/16" through bolt.
drilling the shaft will be easy, if you have a couple new drill bits.

Slide the pipe added adapter on the shaft, tighten the Grade-8 5/16" through bolt,,,
and go blow some more snow,,,, :cool2:

Even if I were to get a new adapter from Surplus Center,,,
I would add a piece of welded pipe before the initial use.
That adapter is too lightly constructed for this application,,, IMHO,,,

That is my thought. I have nothing to lose by welding it back together and adding a collar. If that doesn't work, I can order another one.
There is quite a bit of difference between the 1.5” keyed shaft ujoint with its 1/2" thick walls and this adapter.

Aaron Z

 

[zzvyb6]

OK, this is similar to other situations I've been in. Here is what I would do: Buy the replacement part, maybe for a slightly better supplier, better material, and more careful use of it. Then I would fix the old part, weld with a collar if possible, use round stock as a form and keep it on the shelf. If the driveshaft doesn't line up properly, I would get it into a better position to keep the out-of-plane shaft bending moments to a minimum. That most likely split the adapter. Make sure the inner U-joints line up without a phase angle or 90 degrees off.

 

[D2Cat]

Buy a new coupling. You can get them at most any farm store. If you're concerned about the lock bolt staying in place, drill a hole in the top and insert a wire to hold it. Do it right this time and your tractor probably won't destroy it.

It looks like one side of the coupling had been separated for a while, you just ripped it free.

 

[aczlan]

Buy a new coupling. You can get them at most any farm store.

Not around here, nether Tractor Supply or Runnings carry them. This is going from a 1.5" keyed shaft to a 6 spline 1 3/8" PTO

If you're concerned about the lock bolt staying in place, drill a hole in the top and insert a wire to hold it. Do it right this time and your tractor probably won't destroy it.

The bolt was in there, but it sheared when things came apart, I am pretty sure that the failure mode was the set screw loosening up and it starting to wobble from there until it split on the keyway.

It looks like one side of the coupling had been separated for a while, you just ripped it free.

It rusted since it broke, but that day it was all fresh, no rust. I played with the torch today seeing if I could get the coupling back in place and it came right off of the PTO stub/
Looking at it, there wasn't much weld holding it together (1/8"?) and the weld stopped/started right at the keyway. In beating it back into round, I managed to bend up the keyway, so I am going to just order a new one.

OK, this is similar to other situations I've been in. Here is what I would do: Buy the replacement part, maybe for a slightly better supplier, better material, and more careful use of it. Then I would fix the old part, weld with a collar if possible, use round stock as a form and keep it on the shelf. If the driveshaft doesn't line up properly, I would get it into a better position to keep the out-of-plane shaft bending moments to a minimum. That most likely split the adapter. Make sure the inner U-joints line up without a phase angle or 90 degrees off.

I haven't been able to find another supplier, but the ujoints were lined up. The ujoints going out to the blower have a rectangular shaft so they cannot be out of alignment and I made sure the back ones were aligned when I put the rear gearbox on.


Aaron Z

 

[aczlan]

I think I may have found the cause of the breakage, two pieces of patio block:

They had slid in under the paddle in the center of the auger and probbaly slowly jammed it (so it wasn't an instant shock that would snap a shear pin).

Aaron Z