2nd shear bolt broken

[PILOON]

All talk of sheering bolts has me worried as not one sheered yet this year.
Oh, wait still more snow to come.

Being on a gravel road it is often the city plow that buries rocks in the plow berms.
(That's my excuse and I'll stand by it)

With fingers crossed, when I do sheer one I hope it is above freezing.

 

[SylvainG]

I guess I'll have to call tomorrow. They are in Ontario and it's a Family day holiday there.

But found this further down the manual, so twice there they mention grade 8.8 for the PTO shear bolt. Don't know why the original was a grade 6.8...

 

[number two]

FWIW,I've never seen a 6.8 bolt thread.
4.8,8.8 & 9.8,but never 6.8.
I have to wonder if the bolt head is poorly stamped?
Good Luck!

 

[mikester]

I thought I was doing well this season breaking no shear bolts. This weekend I've broken three.

Not the end of the world, I have a big 50 lb box of 5/16 carriage bolts. Why do I use carriage bolts? Because I have a big box of them. Grade 5.

 

[SylvainG]

FWIW,I've never seen a 6.8 bolt thread.
4.8,8.8 & 9.8,but never 6.8.
I have to wonder if the bolt head is poorly stamped?
Good Luck!

Yeah, if you look at the posted picture, there is like a dimple on the left side between both halves. That's what I thought it was, 8.8. I'll get confirmation from them today.

 

[SylvainG]

Gave them a call. They confirmed that it's an 8.8, so that 6.8 is a misprint.

Now all I have to go get are grade 2 1“ 1/4"D shear bolts and locknuts for the auger.

 

[msb1766]

All this talk about shear bolts made me go and check my stash, got 5 of each, have not broken one in a few years, Then I checked the shear bolts on the blower and found the impeller shear bolt loose.
That would have probably broke as we are supposed to get 8-12 inches tonight into Friday.
So everyone make sure you have spares as well as make sure they are tight!!

 

[hube2]

So everyone make sure you have spares as well as make sure they are tight!!

I would say snug. They should be just tight enough to not wiggle. If they can wiggle they will break faster and if you over tighten them then you can weaken the bolt. I found this out on my first blower, couldn't figure out why I was snapping bolts. It was because I was cranking down on them instead of just tightening enough to not wiggle.

 

[SylvainG]

And from what I read, if you tighten them too much, the friction between the plates will be too much and you'll end up with damage instead of a broken shear bolt.

There is a reason it's a locknut and not a lock washer.