Constantly breaking shear bolts on my cutter....help?

[MESSMAKER]

Do you have a welder?:laughing::laughing:

 

[Trophyduck]

I feel it is both. If I don't turn the wheel it engages more harshly.....but with the angle correct, not as bad....So nice to actually use it a few times now without replacing the bolt

 

[PJSprog]

I had the same issue with a 6' HD King Kutter. Warranty says you can use nothing but grade 2 shear bolts, but I had the same problem. Just engaging the PTO would shear the bolt. So I stepped up to a grade 5 and no problems since. Like you said, cutter is useless if it keeps shearing the bolt.

Same here, but with their 5' cutter. I broke the bolt on that thing the second time I started it. After shearing a bolt each of the first three times I mowed with it, I went to grade 5. Haven't broken one since.

 

[Gary Fowler]

Brother in laws bush hog sheared bolts so bad that even at idle when engaging it would shear. Sometimes it would shear just mowing along in short grass. We tried grade 5 bolts and still sheared, finally I drilled out the shear pin hole to 1/16" oversize and now it works for a long time without shearing.

 

[Guidshir]

I have a Titan flail with hardly any hours on it and after the factory shear bolt on the driveline that came with it broke, they break every time now within a couple minutes of starting. So it doesn't shear on PTO engage, it shears in regular grass. Today I tried a grade 5 and it still broke quickly.

What I am trying to figure out is why it looks like there is groove for bearings. Makes no sense but the main part of the shaft is not a tight fit at all.

 

[WranglerX]

I have a Titan flail with hardly any hours on it and after the factory shear bolt on the driveline that came with it broke, they break every time now within a couple minutes of starting. So it doesn't shear on PTO engage, it shears in regular grass. Today I tried a grade 5 and it still broke quickly.

What I am trying to figure out is why it looks like there is groove for bearings. Makes no sense but the main part of the shaft is not a tight fit at all.

Maybe it threw out all the little balls first time it broke? Needs further investigation...

Dale

 

[Guidshir]

I agree, but I don't understand why there would even ball bearings in there. They would be lost every time the shear bolt broke and it's not like it would need to spin smoothly. The purpose would be only to take up that space. I think I'll move to a slip clutch PTO shaft and be done with it.
Maybe this one
King Kutter Rotary Tiller Pto Shaft with Slip Clutch code 147122: Amazon.com: Industrial & Scientific

 

[aczlan]

It looks like there is/was a setscrew on the far side (see the little hole through the groove on the bottom of the shaft side) so that it doesn't separate when the shear pin breaks.
The groove is probably for grease to go around the joint.
I have a similar joint on a tiller and it has a large circlip to keep the two sides together when the shear pin breaks.

Aaron Z

 

[Guidshir]

Thank you, that does make sense. So the set screw would have to have a rounded end and would fit in the groove to keep the two sides from being separated and still allow the end to spin freely. I never looked at it closely until the factory shear bolt broke and by then it had already separated. Looking at it now I don't ever remember seeing that set screw there, but I can see why I would miss it, and if it was loose it would easily be lost during regular use.

 

[RTBee]

I'm wondering why there is a shear bolt at that end anyway. Isn't that the end that attaches to the tractor? If there is a shear bolt at the other end (which it is on the one I have) then is there a real need to have two? If not, would it not be possible to just bolt it together at this end? No shear bolt. Just rely on the one at the mower end?