Fan shear bolts

[Toyboy]

Out of the blue today I sheared 2 fan bolts, the ones that pin the fan to the shaft....why???

We had about 3" of wet heavy snow last night. The first one went when I was clearing what the plow piled up across the drive, had the rpm's up, so just take it slower, .. OK....my bad.

I didn't have any extras so I substituted an auger bolt. Well that lasted about 10 minutes. This time clearing the drive with just plain snow & going slow w/ rpm's up. WTF!!

Replaced it with another auger bolt and finished the job. I've never sheared one of those in the 5 years I've had the blower and took out two today, don't make sense to me.

I need to get a few from the hardware store to tide me over till I can get to my dealer for the correct bolt but I can't remember the bolt grade. Can you help?

 

[Diydave]

Out of the blue today I sheared 2 fan bolts, the ones that pin the fan to the shaft....why???

We had about 3" of wet heavy snow last night. The first one went when I was clearing what the plow piled up across the drive, had the rpm's up, so just take it slower, .. OK....my bad.

I didn't have any extras so I substituted an auger bolt. Well that lasted about 10 minutes. This time clearing the drive with just plain snow & going slow w/ rpm's up. WTF!!

Replaced it with another auger bolt and finished the job. I've never sheared one of those in the 5 years I've had the blower and took out two today, don't make sense to me.

I need to get a few from the hardware store to tide me over till I can get to my dealer for the correct bolt but I can't remember the bolt grade. Can you help?

You can get by with a grade 3 or less bolt, but use what the mfg recommends. Could be the fan hit a rock, or got something caught between the fan and housing. A snow jam can cause it to shear, too. Some snows are wetter than others, and if ground temps are high, and you have surface melting, you might need to lift the blower, so the wet sticky stuff don't get into the fan, in the first place. Also check the bearings, you never know, till one goes, sometimes...

 

[SLIMSHADIE]

As per manual, grade 8 on fan, grade 5 on auger

 

[Toyboy]

Thanks guys, appreciate it.
Merry Christmas

 

[KeithG]

To anyone using a Kubota SnowBlower that uses a shear bolt with the
specifications 1/4" x 1-1/4" Grade 8 shear bolt be careful as this
specification does NOT match what the dealer will give you.

Specifically a grade 8 bolt will usually be only partially threaded and this
makes a big difference. The bolt I received from my Kubota deal was
COMPLETELY threaded. This makes a difference of 1,250 pounds of
shear force!

A grade 8 bolt has a shear force of 4,418 lbs of shear force if it is not
threaded. A grade 8 bolt that is threaded has a shear force of 3,177 lbs
of shear force.

I will create a topic about shear bolts/grade bolts to give complete
information and details so you can figure out what you can use or
substitute if necessary.

Thanks,
-Keith

 

[Grouse Feathers]

According to the BX5455 manual (same as the 5450 but with the hydraulic chute) the fan takes a grade 2 bolt. Just buy standard grade 2 - 1/4" NC x 1 1/4" bolts at the hardware. The augers take a special shear bolt a grade 5 - 5/16 NC x 2 1/4" bolts with a machined groove.

(added) Some grade 2 - 1/4" x 1 1/4" bolts will be completely threaded and some will not. The ones I got from the hardware were completely threaded the ones from the dealer were not. The threaded ones will work, but if you have trouble with breaking you might look for some not completely threaded.