Snow Shear bolt question

[jaydee325]

Yeah, I have the manual. That's where I got that clip from. Looking locally, I can only see snowblower shearbolt in a size longer than 1-1/4" hence why I asked if any type of grade 2 bolts would work since by the design of the safety shear method used by that blower, it's not going to shear at those groves anyway.

I'm not sure I understand. Are you going to the local hardware store, big box store, etc and asking for a snowblower sheer bolt in the 1/4 x 1 1/4 size? Just ask for a 1/4" x 1 1/4 grade 2 bolt. My local Menards has a 8 pack for .87 cents.

 

[Captain Dirty]

As I wait the arrival of my new 68" MK Martin Meteor snow blower, I have a question regarding its auger shear bolt. Not knowing if it comes with spares, I want to be prepared. According to the manual, the shearbolt (#16 in the following image) is bolted between the two metal plates, one attached to the sprocket (#17) and the other attached to the auger shaft (#15)

View attachment 684987

Now, since snow blower shear bolts usually have two groves where the auger and shaft meets to 'give' when too much force is applied to the auger, in the Meteor's case. these are useless, right? Would a standard 1/4" x 1-1/4" grade 2 bolt and nut would suffice? The manual mentions "Shearbolt 1/4x1 1/4 #2" but I have a **** of a time to find these. All I find are 1/4" x 1-7/16", 1/4" x 1-1/2" or 1/4" x 1-3/4", not 1/4" x 1-1/14".

My Lorenz has a somewhat similar configuration. A short length of flat stock is welded perpendicularly to the end of the auger shaft. Each end or "ear" of the flat stock is drilled so 2 shear bolts pass through the ears and corresponding holes in the chain-driven sprocket. I suspect the "Shearbolt 1/4 x 1-1/4 #2" means two (2) bolts are required, and the sketch does not show the second one. From an engineering standpoint it makes more sense to have 2 bolts to deliver the torque evenly. If the second bolt were not required there would be no need of the second ear, and there would need be some sort of pin and socket arrangement to align the shafts. When the machine arrives, examine it closely, and also note the head of the provided shear bolts. Read the manual to see if it specifies the grade. Some on this forum have spoken against grade 2 bolts claiming that they are too soft and will bend and be difficult to remove while higher grades are more brittle and break more cleanly. Use the grade the manufacturer specifies. If not specified use the same grade as supplied.

I agree with the comments that, if the extra length does not interfere with other parts, the length doesn't matter. If a longer bolt will fit, you might grind a taper so the bolt is easier to install and the nut easier to thread with numb hands. Also lock nuts would likely be abetter choice than plain nuts.

 

[SylvainG]

My Lorenz has a somewhat similar configuration. A short length of flat stock is welded perpendicularly to the end of the auger shaft. Each end or "ear" of the flat stock is drilled so 2 shear bolts pass through the ears and corresponding holes in the chain-driven sprocket. I suspect the "Shearbolt 1/4 x 1-1/4 #2" means two (2) bolts are required, and the sketch does not show the second one. From an engineering standpoint it makes more sense to have 2 bolts to deliver the torque evenly. If the second bolt were not required there would be no need of the second ear, and there would need be some sort of pin and socket arrangement to align the shafts. When the machine arrives, examine it closely, and also note the head of the provided shear bolts. Read the manual to see if it specifies the grade. Some on this forum have spoken against grade 2 bolts claiming that they are too soft and will bend and be difficult to remove while higher grades are more brittle and break more cleanly. Use the grade the manufacturer specifies. If not specified use the same grade as supplied.

I agree with the comments that, if the extra length does not interfere with other parts, the length doesn't matter. If a longer bolt will fit, you might grind a taper so the bolt is easier to install and the nut easier to thread with numb hands. Also lock nuts would likely be abetter choice than plain nuts.

No, there is only one shearbolt for the auger so the 2 is definitively the grade. For the shaft shearbolt, they says #5 so I doubt there are 5 shearbolts on the shaft

What I was worried about the length, is the distance between the sprocket shear plate and the blower casing. I'm not sure if a longer bolt would be more problematic to insert, but if I can use standard grade 2 bolt, I'll find that at my local hardware store.

I'm not sure I understand. Are you going to the local hardware store, big box store, etc and asking for a snowblower sheer bolt in the 1/4 x 1 1/4 size? Just ask for a 1/4" x 1 1/4 grade 2 bolt. My local Menards has a 8 pack for .87 cents.

My experience with snow blowers are for self-propelled 27" and 29" wide 4 stroke engine snow blowers and these have shearbolts with groove (where the auger and shaft meet) like shown in the picture below. Owning a PTO driver snow blower is new to me so I'm going from past experience. From what I gathered here, plain grade 2 bolts will suffice for this Meteor snow blower. I have no problem paying just a few cents per shearbolts instead of a few dollars

 

[jaydee325]

My experience with snow blowers are for self-propelled 27" and 29" wide 4 stroke engine snow blowers and these have shearbolts with groove (where the auger and shaft meet) like shown in the picture below. Owning a PTO driver snow blower is new to me so I'm going from past experience. From what I gathered here, plain grade 2 bolts will suffice for this Meteor snow blower. I have no problem paying just a few cents per shearbolts instead of a few dollars

View attachment 685034

Like I said above, nothing special.:thumbsup:

 

[TerryR]

My experience with snow blowers are for self-propelled 27" and 29" wide 4 stroke engine snow blowers and these have shearbolts with groove (where the auger and shaft meet) like shown in the picture below. Owning a PTO driver snow blower is new to me so I'm going from past experience. From what I gathered here, plain grade 2 bolts will suffice for this Meteor snow blower. I have no problem paying just a few cents per shearbolts instead of a few dollars

View attachment 685034

That looks like a special bold that has been reduced in size at the shear zones so it shears at a lighter load like it was a smaller diameter. You don't want that unless that is what's specified by the manufacturer.

 

[SylvainG]

Well, the manufacture only mentions shearbolt and having only owned smaller snow blower like MTD, that's the only shearbolt I've known. Now I know better

 

[Captain Dirty]

With my curiosity piqued, I went to MK Martin's site and downloaded the manual for S[now]B[lower] 68 Rev[ision] 17-6.

Page 18 shows the exploded diagram (including the OP's attachment) and parts listing. The listing shows
Item #16; 68 Part # OL [Obtain Locally]...Description Shearbolt 1/4x1 1/4 #2 c/w [??complete with??] ln [lock nut]; Qty 1.

Page 23 shows the complete shear yoke with the shear bolt
Item # 71: Bolt & Nut M8x50 cl 8.8; Part # 165.000.571; Qty 1.

Page 33 shows
PTO Shearbolt M 8x50 - 8.8
Auger Shearbolt 1⁄4 x 1 Gr #2
...
All fasteners are Grade #2 unless otherwise specified.

The OP may have a more recent manual, but the discrepancy of a SAE grade 5 vs metric grade 8.8 on the PTO shaft shearbolt and the internal discrepancy on the length of the auger shaft shearbolt would give me pause to wait and see what is fitted to the machine.

 

[CS2210]

I have the meteor sb54 that I purchased new in 2017. It came with a bag of extra shear bolts. They are just a grade 2 bolt, I can't remember right off if it came with two different length bolts or not but for some reason I think it did. Either way you should have a few to get ya going and maybe take to the store and pick up some of the same. This is the 4th winter with this blower and have only replaced 2 shear bolts. I also have a paved driveway so that helps.

I haven't had any issues with the blower seems well built and I'm sure you will be happy with it.

 

[WranglerX]

You can buy bolts and nuts at Tractor Supply by the pound, no reason not to use what manufacturers recommend and just expect them to "operate" like the design specs call for....

Dale

 

[SylvainG]

My 1000 feet private road is a mix of dirt and gravel. A few years ago, I had someone open it up with his PTO attached snowblower to his tractor. He complained a few times that he broke his chain doing my private road, so don't know how well my blower will take it. I have a 800 ATV with a 48" plow and a 27" snow blower currently. When the plow can't lift the snow over the snow bank anymore, I use my snow blower to widen the road. I break about one to two shear bolts per clearing. Mind you, don't know if it matters but the 27" snowblower auger is about 1/2" from the casing (and where the gravel gets caught) while the Meteor snow blower has over an inch of spacing between the casing and the auger.

@CS2210, Glad to read yours came with extra. That's what I'm hoping too.

@Captain, yep, I plan on waiting for what comes with it and see if I can get equivalent locally. (probably can).

Thanks all. This is a great site. I'm usually on reddit but from what I can see, tractors are too old school for the reddit gang I couldn't find a subreddit dedicated to tractor maintenance, just a generic 'Tractors' subreddit.