B2789 snowblower problem

[sheepfarmer]

Well we are probably all going to drown in the semantics of all this, but in another part of the snowblower, the auger and fan have some boltlike structures that Kubota calls shear bolts even though they fit NIW's definition of shear pins. "Always use special grade 5 shear bolts on fan assembly and special grade 5 grooved shear bolts on auger." Similar in parts list. Come with nuts and washers.

 

[Russell King]

I agree that a bolt is a bolt and a pin is a pin. Either can act as a shear device.

Most shear devices involved in the tractor PTO world are bolts so that a nut can hold them in place from flying out due to rotational force.

Most I have seen are grade 2 but any grade could be used if designed for that grade. It would just be using a smaller diameter to get similar shear strength. Again most I have seen are a about 5/16 or 3/8 shank diameter and are supposed to be long enough to have the threaded section outside the joint.

I often buy fairly long bolts and add flat washers under both the head and nut to keep it somewhat balanced and have smooth shank through the entire yoke.


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[KeithG]

Well we are probably all going to drown in the semantics of all this, but in another part of the snowblower, the auger and fan have some boltlike structures that Kubota calls shear bolts even though they fit NIW's definition of shear pins. "Always use special grade 5 shear bolts on fan assembly and special grade 5 grooved shear bolts on auger." Similar in parts list. Come with nuts and washers.

It was the "semantics" that was driving me nuts trying to find a "grade 8 shear bolt" for my Kubota snowblower from a local tractor shop, hardware store or home depot. This is why I learned everything I could about the requirements for the bolts used to provide shear protection for specific equipment.

If I had gone into any of the shops and asked for a "fully threaded grade 8 bolt" then they all would have known exactly what I needed and given it to me.

All I am trying to do is clarify the "semantics" so the next person can identify exactly what they need. I know it would have saved me a lot of time and effort.

 

[North Idaho Wolfman]

KeithG, and all.

I am NOT saying a Grade 8 bolt is a shear bolt, a shear pin or anything else and I never did!

The bolt/ pin / holding device in this instance is not supposed to fail!
It's not supposed to come apart!
That connection failing while operating would result in a flying PTO drive shaft, not something you want to happen!

You would never use a grade 8 as a shear device