I was all set to cut the grass and enjoy a beer on the deck wen done and this happened

[muncybob311]

It's been a good day until this afternoon. Had just started to mow and backed up at a bit of a quick pace when I caught the mower deck on the horse trailer. At first I just thought I didn't have the quick attach secured 100% but it's a lot worse than that. Hoping Terry can send me the parts needed so I can start looking for a good welder that will come to our house.

 

[CliffordK]

Ok, so that is some kind of big shaft that was snapped. Are there parts that need to be welded to that shaft that you don't think will come with the replacement part?

Or do you wish to try to fabricate a new part from scratch?

The first thing I'd do is try to get both ends of the shaft removed from your machine, you'll need it out no matter how you repair it.

You should also look at the condition of bearings/bushings/seals when you have it open.

If you are looking for local assistance suggestions, then an approximate location will help.

 

[mllud]

It looks like there was a previous weld repair done around the bearing housing.
One idler pulley also looks like its rubbing the deck. Possible bad bearing.
New shaft needed to repair that break.
On edit it looks like someone actually welded the bearing race in place. Destin to fail if so
The shaft also has some staining around the perimeter on the right edge like it could have had a fracture for some time.

 

[CliffordK]

I'm not seeing the wear you're seeing on the pulleys. The two cast steel pulleys have a bright polished inner surface where the belt runs.

I would inspect the shaft carefully, but at this point, it is BROKEN. There appears to be a keyway at the lower part of the shaft in the photo, and it does appear to show some nearby darkening in the photos, but one has to look at the actual pieces.

 

[mllud]

I do think that I was seeing a polished edge on the idler pulley where the belt rides as you said.

 

[zzvyb6]

I'd change the belt as long as it's on the bench...

 

[ponytug]

It's been a good day until this afternoon. Had just started to mow and backed up at a bit of a quick pace when I caught the mower deck on the horse trailer. At first I just thought I didn't have the quick attach secured 100% but it's a lot worse than that. Hoping Terry can send me the parts needed so I can start looking for a good welder that will come to our house.

Ouch!

It looks like it sheared completely through without a previous crack, which to me is a pretty impressive hit.

What does the inside of the Q/A plate look like? I.e. what is the other end of the pin look like? PT has a few different designs. From the armchair over here, it looks almost as if it was a round head threaded pin, that sheared at the top of the thread.

Let us know what Terry comes up with. How old is your 422?

All the best, Peter

 

[CalG]

shear bad luck!

 

[Hay Dude]

I thought he was going to say “I was all set to enjoy a beer on the deck, when
my mother in law rolled up”

 

[muncybob311]

Appreciate all the "eyes" on this. I'll uncover the deck later today and look at some of the observations although I've never had a problem with any of the pulleys. Yes, that belt looks sad...funny thing is I ordered a new belt many years ago intending to replace the original, just never got round to it so I thought lets see just how long it will last. The PT has over 1400 hours on it and at least 60% of that time was running the mower.
Def on borrowed time!

You would think I caught the deck going fast but as us PT owners know, I don't think the tractor exceeds 10mph which makes me think there was a pre existing condition for the part to fail.

Going to clean things up a bit and take some better photos before contacting Terry. Wife said maybe the part can be welded back together, not sure I'm comfortable with that but will run it by Terry.

Thankfully I kept the contact info on a welder from years ago that did some fine wok for me then, probably call him later today.

 

[muncybob311]

Here are some pics after a bit of cleaning. The QA plate looks OK? I cannot see any stress fractures?

 

[ponytug]

Here are some pics after a bit of cleaning. The QA plate looks OK? I cannot see any stress fractures?

I think you were just really unlucky. I also suspect that there was probably a metal defect in the axle, and you clipped it just right to shear it. I can't see any sign of a pre-existing crack that spread in any of your photos.

I think that in the hands of a great welder with the right tools, anything can be welded. That said, I think that welding at your break is a high stress location and I think it would require cutting enough of a gap to weld in, and then a great welder, but even then there will be a heat affected zone that will be prone to failure. I wouldn't go that route if it were me.

I suspect that the repair is a new axle, then gouging or plasma cutting the old end out of the Q/A plate, and then welding the new one in. That would be fairly easy for a competent welder, and would get the heat affected zone away from the highest stress area.

Good luck!

All the best, Peter

 

[RayIN]

I think that in the hands of a great welder with the right tools, anything can be welded

Yep. I watched a man weld 2 sections of aluminum wrapper out of a pack of Pall Mall's together.
Others were betting on the outcome. That Navy-trained welder won nearly $1,000 with that feat.

 

[CliffordK]

That looks like a pretty wicked grain structure, but I'm not quite sure what what it would be like to break the unbreakable.

I assume the part with the nut can just be knocked out towards the nut... hopefully. Then once off you can try to salvage the nut.

That is an interesting method to use a short sleeve between the base plate weld and the pivot point which effectively isolates the heat affected zone.

Would rounding the corners slightly on that short sleeve help reduce the single point stress riser?

A good machinist should be able to build the part from scratch. Basically sizing and threading a rod. And then get it welded on. I'd do it all in the machine shop.

I'd be tempted to go with steel that wasn't the original steel that failed.

 

[RayIN]

That looks like a pretty wicked grain structure, but I'm not quite sure what what it would be like to break the unbreakable.

I assume the part with the nut can just be knocked out towards the nut... hopefully. Then once off you can try to salvage the nut.

That is an interesting method to use a short sleeve between the base plate weld and the pivot point which effectively isolates the heat affected zone.

Would rounding the corners slightly on that short sleeve help reduce the single point stress riser?

A good machinist should be able to build the part from scratch. Basically sizing and threading a rod. And then get it welded on. I'd do it all in the machine shop.

I'd be tempted to go with steel that wasn't the original steel that failed.

Depends, I always want the first part to break to be the easiest and cheapest to replace.

 

[CliffordK]

Depends, I always want the first part to break to be the easiest and cheapest to replace.

True, and I've wondered about upgrading things like upper and lower control arms on vehicles that seem to get rapidly destroyed in an accident. If the control arms are made stronger, then perhaps one would have a more costly frame repair.

 

[muncybob311]

So I spoke to Terry and he thinks a good welder can take core of the repair. Apparently the "axle" has a shoulder on it between the ring and the QA plate which keeps the axle stationary. We should be able to grind the ring bracket off the QA plate, pop out the small piece of the axle and the larger piece from the mower deck itself and reinsert the new axle and then weld back onto the QA plate. I asked if the heat marking on the inside of the QA plate is a problem since the small ring will be welded onto the same spot and he said no.

Just waiting to hear if they have the axle in stock, otherwise it's a whole assembly and 4X the $$.

 

[ponytug]

So I spoke to Terry and he thinks a good welder can take core of the repair. Apparently the "axle" has a shoulder on it between the ring and the QA plate which keeps the axle stationary. We should be able to grind the ring bracket off the QA plate, pop out the small piece of the axle and the larger piece from the mower deck itself and reinsert the new axle and then weld back onto the QA plate. I asked if the heat marking on the inside of the QA plate is a problem since the small ring will be welded onto the same spot and he said no.

Just waiting to hear if they have the axle in stock, otherwise it's a whole assembly and 4X the $$.

That sounds like progress.

If it turns out that PT doesn't have the axle in stock, and you have access to a good welder, if it were me, I would price out the alternative.

All the best, Peter

 

[CliffordK]

So I spoke to Terry and he thinks a good welder can take core of the repair. Apparently the "axle" has a shoulder on it between the ring and the QA plate which keeps the axle stationary. We should be able to grind the ring bracket off the QA plate, pop out the small piece of the axle and the larger piece from the mower deck itself and reinsert the new axle and then weld back onto the QA plate. I asked if the heat marking on the inside of the QA plate is a problem since the small ring will be welded onto the same spot and he said no.

Just waiting to hear if they have the axle in stock, otherwise it's a whole assembly and 4X the $$.

Thanks. I was wondering if it was a hole through the backing plate and a weld on the back side, although it looked smooth in the photos. Apparently not.

Grab a spare ring when you do it.

 

[muncybob311]

A spare ring would have been a good idea if indeed there was a ring at all I realized when the replacement part was received that the flange/collar was what I thought was a retaining ring. Just had to remove the old part and smooth out the area, take some measurements and then weld the new part's collar to the QA plate. All went well,cut the grass perhaps for the final time this year.