Catastrophic Hub Failure

[jyoutz]

12 ga #6 shot for your little buddy there...
CaBOOM...

Tarantulas aren’t venomous or aggressive. They just walk slowly going about their business and usually run away from people.

 

[Lil Foot]

This guy was definitely on a mission- headed straight east. I got in front of him till I could get the camera ready, but he just went up & over my shoe. Could not get a decent photo of him on the ground, so I threw that white rag in front of him & he just motored over it like it wasn't there.

 

[North Idaho Wolfman]

This guy was definitely on a mission- headed straight east. I got in front of him till I could get the camera ready, but he just went up & over my shoe. Could not get a decent photo of him on the ground, so I threw that white rag in front of him & he just motored over it like it wasn't there.

Seen the biggest ones when our 5th wheel was in Strawberry / Pine, AZ when we were there.
The ones there are harmless, but they still freak me out!

 

[NorthwoodsLife]

Those tarantulas get a bad rap, because they are large and mean looking. They are venomous, but not much. Think a mild bee sting. What hurts the most is the fact that the fangs can be as large as wooden toothpicks. Stick a toothpick into your arm, you'll get the idea. Raised a son who had to have a Tarantula as a pet. Got him one. I used to let it crawl over me sometimes. If the sand-sized brain doesn't feel a threat, you're good. Chilean Red I think the breed was called. Leave 'em alone and they'll leave you alone. Whip Scorpions or Vinagaroos are a different story. Harmless but they seem to chase you.

Anyway.

Glad you were able to fix your K, MacGyver style.

 

[PaulL]

Don't see how wheel weights would usually impact a hub - the weight goes from the weight straight down the tires onto the ground. Except the backhoe - when it's in the air on the outriggers then those weights are all pulling on the hub. They do recommend you not ballast the tires on a backhoe equipped tractor, so maybe that also goes for wheel weights? Other than the backhoe I'd say it's not the weights.

 

[Nicksacco]

Nice job getting the machine back to the home @Lil Foot !
Please refrain from doing wheelies from now on....

 

[Runs With Scissors]

Glad your ok.

Like you said, that could have been way worse.

Nice "bush fix" though.

 

[GreensvilleJay]

re: wheel weights
two ways they can do damage
1) extra mass when starting to roll and stopping
2) if not 100% parallel to rim ,every rotation stresses the hub 'in-out-in-out'

All the mechanical engineers can apply the proper terms

 

[Yooper]

Glad there was no human injury! Very clever bush fix on your part!

 

[Lil Foot]

Except the backhoe - when it's in the air on the outriggers then those weights are all pulling on the hub.

I try to always keep the rear tires on the ground when using the BH- more points of contact, more stability.
Sometimes not possible when on some sidehill, but I try.

 

[NorthwoodsLife]

re: wheel weights
two ways they can do damage
1) extra mass when starting to roll and stopping
2) if not 100% parallel to rim ,every rotation stresses the hub 'in-out-in-out'

All the mechanical engineers can apply the proper terms

Yep.

I might as well ad: Every time you hit a bump the tractor goes a bit airborne and that extra weight is transmitted to the hub flange.

 

[trial and error]

Your going to make me do at least a visual inspection on mine. I still have to old style. But to have that break while plowing this winter would be a very bad day. Sorry that this happened to you but things like this make some of us look at things we may otherwise not

 

[Lil Foot]

Got a chance to study the break a little.
First, to be clear, the weld did not fail- the steel of the 1/2 hex failed.
The weld probably caused a stressor in the 1/2 hex steel, as it fractured right next to the weld.
Tried to take some detailed pics, but not very successful.
In person, it is obvious that one half of the hex steel failed sometime ago, and hammered on itself repeatedly, producing a very shiny, almost peened surface. (the upper portion of the hex in these pics)
The lower half is definitely a much grainier surface, so I think the top half had been broken for a long time, and the lower half letting go caused the sudden collapse.
There was no rust anywhere, but this is Arizona.

 

[Yooper]

I think your analysis is right on the mark! Stress riser over time was the culprit.

 

[GreensvilleJay]

In looking at picture in post #5 , there isn't a lost of 'steel' where the hub 'disc' is welded to the 'shaft' In section. I'd want a nice thick fillet of weld between the two,or better an additional 1/4" thick 'disc'.

 

[Lil Foot]

I did not want to re-visit this thread, but here we go.
These are the cast steel hubs I replaced the bad originals with.

 

[Lil Foot]

Everything seemed fine until this past week, when I noticed an occasional clank or clunk sound, coming from the rear.
Jacked the rear up with the outriggers & found play in the rear wheels.
Tore it down further and found this:

 

[Lil Foot]

Further diagnosis found that the two halves of the clamping cylinder were bottomed out on each other, without applying any clamping force on the hex axle shaft. There must have been minimal clamping force on high points or maybe paint when I installed them, but they are loose as a goose now.

 

[Lil Foot]

I took the hubs home, and used the lathe to face .125 off the hex clamping end of each half of the clamping cylinders, generating about .250 clearance between them.
I then added a .250 thick spacer & a thicker split washer under the clamp nut .
Hopefully this will solve the problem.
I will re-assemble next trip to the cabin.
3rd pic shows modified clamp (lower) vs un-modified clamp.

 

[Runs With Scissors]

Are you planning on trying to "shim up" that play somehow?