shear bolt ?

[jeff408]

When the shear bolt breaks does this cause some damage to the yoke where the 2 pieces meet and break away. A friend of mine says everytime it breaks it does something to damage it somehow. I am pretty new to this stuff. Could there be anything to this?

 

[irvingj]

If I understand the function of shear bolts correctly, they will always be of a softer material than the splined shafts of yokes... or, at least they'll be scored so they'll break more easily at a preset point. Their function is to protect the yokes/drivetrain. I know of no damage --more than normal wear & tear-- that occurs, unless an incorrect shear bolt is used.

 

[radioman]

perhaps your freind was referring to the elognated hole when the shear bolts breaks alot and/or using a stronger bolt then the shear. If you are breaking shear bolts alot, then something is wrong.

 

[greg_g]

When the shear bolt breaks does this cause some damage to the yoke where the 2 pieces meet and break away. A friend of mine says everytime it breaks it does something to damage it somehow. I am pretty new to this stuff. Could there be anything to this?

If your friend is telling this to you based upon his own personal experience, then he's been using the wrong shear bolts. As Irving stated, it must be softer than the steel through which it is inserted, but also relative to the horsepower rating of the implement transmission. 40hp/GR2 bolt, 80hp/GR5, 120hp/GR8, etc. And the diameter is very critical. If it's the slightest bit too skinny for the hole, it will move enough to cause the elongation of the holes that RM mentioned.

Don't just run down the the hardware store and buy the first bolt you see. Follow the specific implement owner's manual for specs on replacement shear pins, and you usually save yourself a lot of grief in the long run.

//greg//

 

[jeff408]

What I would like to do is to run a shear bolt that is on the soft side. I would rather replace shear bolts all day long than to break something inside of my tractor. But if shearing bolts all the time is going to screw up the driveshaft I will have to rethink how I would want to do things.

 

[greg_g]

I think you missed the point. If you use/install/replace the right shear bolt from the git-go, all those other problems go away.

//greg//

 

[jinman]

perhaps your freind was referring to the elognated hole when the shear bolts breaks alot and/or using a stronger bolt then the shear. If you are breaking shear bolts alot, then something is wrong.

Radioman, have you been watching me operate my cutter?

I have a cutter that's probably gone through 35 or 40 shearbolts. When the outside collar shears the bolt, it slings the two end bits of the bolt to kingdom come and spins on the center shaft. That spinning builds up heat and will eventually do some light scoring of the inner shaft because dirt, grease, metal shavings, etc. inside the joint works as a rolling abrasive. However, the cutter quits working and its sound changes dramatically, so the amount of spinning is normally limited to minimum.

Each time I've popped a bolt (I always use grade 2), my outer collar's hole becomes slightly elongated to the point that it is now an ellipse instead of round. The hole in the center shaft is still round and tight. My ground is so uneven that it's easy to bottom out the stump jumper and blades. Also I have so many football sized hidden limestone rocks that pop up out of the ground and get hit by the mower, until I carry a half-dozen shearbolts with me on my tractor. This cutter is 10 years old and has had lots of abuse and lots of shearbolts.

So, I'd say it is possible to have minor damage to your shaft and collar from shearing even the softest bolts if you pop as many as me. The only way to prevent that is to go to a slipclutch. Personally, I think keeping a slipclutch adjusted is probably a bigger pain than changing shearbolts. I've never had a grade 2 shearbolt be "out of adjustment."

 

[buck12]

[/QUOTE] Personally, I think keeping a slipclutch adjusted is probably a bigger pain than changing shearbolts. I've never had a grade 2 shearbolt be "out of adjustment."[/QUOTE]

I agree. I always thought a slip clutch would be the best option until I spent a couple of hours beating, sanding, and cleaning the one on my tiller after it froze up. Now I prefer the shear bolt on my RC.

 

[smfcpacfp]

I have had shear bolts break on my snowblowers over the years with no ill effects. They have performed their function of breaking before any damage was done to augers, impellers and gearing.

 

[rScotty]

The message I've copied below describes the situation and damage from shear bolts very well. At least it is the same as my experiences and conclusions about shear bolts. Thanks, Jim. In a nutshell: Yes, a shearing bolt and the movement of the shafts after it shears will cause some small damage and wear. No, so far there isn't any better way to protect the more expensive components.
rScotty

Radioman, have you been watching me operate my cutter?

I have a cutter that's probably gone through 35 or 40 shearbolts. When the outside collar shears the bolt, it slings the two end bits of the bolt to kingdom come and spins on the center shaft. That spinning builds up heat and will eventually do some light scoring of the inner shaft because dirt, grease, metal shavings, etc. inside the joint works as a rolling abrasive. However, the cutter quits working and its sound changes dramatically, so the amount of spinning is normally limited to minimum.

Each time I've popped a bolt (I always use grade 2), my outer collar's hole becomes slightly elongated to the point that it is now an ellipse instead of round. The hole in the center shaft is still round and tight. My ground is so uneven that it's easy to bottom out the stump jumper and blades. Also I have so many football sized hidden limestone rocks that pop up out of the ground and get hit by the mower, until I carry a half-dozen shearbolts with me on my tractor. This cutter is 10 years old and has had lots of abuse and lots of shearbolts.

So, I'd say it is possible to have minor damage to your shaft and collar from shearing even the softest bolts if you pop as many as me. The only way to prevent that is to go to a slipclutch. Personally, I think keeping a slipclutch adjusted is probably a bigger pain than changing shearbolts. I've never had a grade 2 shearbolt be "out of adjustment."