PTO Shaft to Gearbox Bolts Keep Breaking!

[wirlybird]

Why do you seem to prefer a pin to a bolt?

It was just a thought.
Main idea is a constant diameter of the pin, no threads.
When you're out doing a 15 acre field with no obstacles you get time to think of things!

 

[wirlybird]

Only advantage I can see is how trivial it is to put the lynch pin in to hold it.

That brings up another disadvantage - there will potentially be some shear -- probably not much but non-zero -- on the lynch pin holding the main pin, and who knows what those are made of. Of course you can use a bolt and nut there... with a washer... ok now we're way beyond the cost of just a bolt.

Yea, I was thinking a small bolt.
Anyway, it was just an idea.

 

[old and tired]

Taking another stab at this.

The PTO only breaks the threaded side of the bolt.

My guess (correct me if I'm wrong) you would pull out the broken bolt and insert another bolt in the same direction (yes? or no?).

Try inserting the bolt in the opposite direction, if it still breaks the threaded side, I'm at a loss...

Are you still breaking them?

 

[SPYDERLK]

Taking another stab at this.

The PTO only breaks the threaded side of the bolt.

My guess (correct me if I'm wrong) you would pull out the broken bolt and insert another bolt in the same direction (yes? or no?).

Try inserting the bolt in the opposite direction, if it still breaks the threaded side, I'm at a loss...

Are you still breaking them?

I dont think he has ever sheared the longer bolt he put in that has a shank spanning both shear points. ???

 

[airbiscuit]

I'm not sure he ever tried a longer bolt, a bigger bolt (14mm), or duct tape around it to preserve the evidence. Until that happens, these are just theoretical solutions.

 

[SPYDERLK]

I had put a longer bolt in it and it has about an hour or so on it.
Going to take a look once the storms pass.
Thing is though I use the 1/2 by 3 bolts on all of my cutters and this is the only one having issues!
May also swap out the shaft and see what happens.

I dont think he has ever sheared the longer bolt he put in that has a shank spanning both shear points. ???

I'm not sure he ever tried a longer bolt, a bigger bolt (14mm), or duct tape around it to preserve the evidence. Until that happens, these are just theoretical solutions.

Yup. The problem is fatigue at the stress riser in the thread root.
- The longer bolt should do it.

 

[wirlybird]

Yup. The problem is fatigue at the stress riser in the thread root.
- The longer bolt should do it.

Yes, longer bolt seems to be doing better.
Going to pull it when I get time to see how it looks.

 

[Travis_R]

wirly bird,

Did you ever find out what the problem was?

 

[airbiscuit]

Yes, longer bolt seems to be doing better.
Going to pull it when I get time to see how it looks.

Maybe the longer bolt worked

 

[wirlybird]

Longer bolt is holding up so far. Been busy so not much time to look at it!