snapped chain.....twice

[ihuntbear]

my experiance is if the shear bolt is loose the hole will wear,making it oval.Also about rocks getting into the chain,the augur is designed to pull snow from the sides of the machine and throw it into the impeller.If you think rocks are getting into the chain just get a guard for it.I think your shear bolts are to high a grade.Sometime they get labeled wrong.Use grade two on augur and grade five on impeller and change the chane to a higher grade chain.If its a 60c chain go to a 60hcrw

 

[kevinj]

my experiance is if the shear bolt is loose the hole will wear,making it oval.I think your shear bolts are to high a grade.Sometime they get labeled wrong.Use grade two on augur and grade five on impeller and change the chane to a higher grade chain.If its a 60c chain go to a 60hcrw

Most all shear bolts only ride on the bolt and the holes do wear. However on a blower the parts are under power and should not move around too much when in use.

The Rad blowers are unique as they clamp 2 plates rather than going thru a shaft. Whatever the mechanism the bolt must be the drive or it cannot shear.

Also Rad who makes the blower in question clearly states grade 5 shear bolts.

Sometimes a softer bolt will stretch and not shear.

I will stick with what the manufacturer says to use.

 

[SPYDERLK]

I spoke to both of my dealers this morning and they said Kubota does not give a spec for shear bolt torque.

They both did say that they should be snugged and then backed off so the bolt could be rotated but the parts did not rattle around.

They both said too tight and they will not shear reliably.

Hope this helps someone.

I have a Kubota thrower and agree ... but Note that OPs shear arrangement is different than that used on Kubota throwers. His should be snug, but not tight
larry

 

[kevinj]

I have a Kubota thrower and agree ... but Note that OPs shear arrangement is different than that used on Kubota throwers. His should be snug, but not tight
larry

The OP's shear looks EXACTLY like mine except that the New Holland drive is on the opposite side.

Compare post 31 with 42

 

[SPYDERLK]

The OP's shear looks EXACTLY like mine except that the New Holland drive is on the opposite side.

Compare post 31 with 42

Thanks. Didnt see that. They are differemt than mine. ... In that case tho I do not agree with Kubotas advice. If the shear bolt is not snug in that arrangement the joint can open some by spreading. That corrupts the shear. A shaft in tube design does not need to be snug since the shear area is well controlled by the size of the parts.
larry

 

[kevinj]

Thanks. Didnt see that. They are differemt than mine. ... In that case tho I do not agree with Kubotas advice. If the shear bolt is not snug in that arrangement the joint can open some by spreading. That corrupts the shear. A shaft in tube design does not need to be snug since the shear area is well controlled by the size of the parts.
larry

Kubota's advice is JUST snug not loose, but so that the bolt can be rotated some. I assume by light wrench pressure.

Mine is 4 winters old and I have no wear yet by using this method.

 

[Dutch445]

Negative, the bolts will shear when something gets into the augers(or fan) bad enough to stop them, but I think you are getting rocks into your chain, which is before the augers. Thus snapping the chain.

A 2 to 6 inch rock getting in between the chain and the sprocket is probably going to cause a problem.

(Blower picks it up with the snow......snow packs it into the the sides...........gets lodged between sprocket and gear...........snow keeps piling in pushing rock into sprocket.............)

I think we've found the problem.

What lead me to this conclusion was the amount of paint wear (and the pattern) on the blower, in such a short period of time.

I'm with you on this one, sounds and looks like rocks/gravel are running
thru the blower fairly regularly, and the bigger ones may be in the auger,
but smaller ones may very well be in the chain/sprocket area.

 

[Sumpter]

Again I have not had rocks in the chain or sprockets. I have been in the auger. And once in the second stage.

 

[kevinj]

Again I have not had rocks in the chain or sprockets. I have been in the auger. And once in the second stage.

How tight are you putting the shear bolts???? See my post above on dealer recommended torque.

 

[Sumpter]

They are tight, but i am going to loosen them a bit before I use it again. Had to put the blade on since it rain and turned the road to slush. We evn had to get the old TD-6 out to help clear the roads. I found something the tractor had a hard time doing and didn't want to tear it up.