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We got about 12" of snow today and my snow blower lasted only 30 minutes before shearing off one of the 1/4" bolts that holds the rotary blade in place. This is the second time this has happened in as many snow blowing adventures.

What is the right kind of bolt to use for such demanding snow removal?

forrest
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    What does the manual say? It should specify the bolt size and grade. Grade 2 will snap/break a lot faster than grade 5, but other stuff might break before grade 5. 12" is quite a lot, so maybe just need to slow way down in speed. – crip659 Feb 24 '22 at 21:54
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    If it's a new snow blower, you should be speaking with the manufacturer or retailer, not us. That should be covered under warranty. – FreeMan Feb 24 '22 at 22:00
  • I've had the snow blower for about 5 years so warranty is not an option. I slowed down to 1 today and it worked fine until the bolt broke. I'll look into grade 5 bolts. Thank you. – forrest Feb 24 '22 at 22:09
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    Remember those bolts/shear pins are used to prevent expensive parts from breaking. Might also be trying to tell you a bearing is wearing out or some parts need grease/oiling. – crip659 Feb 24 '22 at 22:16
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    Check the manual for your blower. If it tells you that the bolt is a shear bolt, then replacing it with a stronger bolt will only result in you damaging the machine somewhere else more expensive or harder to repair. – brhans Feb 24 '22 at 22:40
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    It's not unusual for shear pins to break, especially if you have a gravel driveway. They're ***doing their job*** when they break. IIRC, my record is three in a single session (granted, my driveway is 500'). If you're breaking them "too" frequently, you may be trying to use a machine that is under-powered for your needs. BTW, warranty won't cover these, as they are "normal wear and tear" (same for the snow thrower's shoes). Also, is your drive gravel or paved/concrete? – Matthew Feb 25 '22 at 16:09
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    How did you "slow down to 1"? It sounds to me like you reduced the throttle. That's not what people mean. They are saying "YOU slow down". Keep the power at full, but walk it into the snow more slowly so it is gulping less snow at a time. – Harper - Reinstate Monica Feb 27 '22 at 00:31
  • Letting it accumulate more than 6" is *your* fault. If you got to a 12" drift you take little bites or you let it ride up. That's my favorite noise in the winter; listening to a blower spool up and down because my neighbor waited until it stopped snowing to do something about it. – Mazura Feb 27 '22 at 22:32
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    @Mazura - next time I'll be sure to get up at 3:00am when only 6 inches have accumulated to do that first run :). – forrest Feb 28 '22 at 02:22
  • Unless there were chunks of ice in the snow or gravel, a grade 2 bolt should work just fine under full load with 12" of snow. I'm in the same boat as @Matthew and it's rare to have one break just from the snow. As far as speed, I usually go just as fast as I can without the snow spilling over the sides. If you try to use it like a plow in 12" of snow, you will definitely break a pin. As far as not letting 6" accumulate...try living in a lake effect area...snow forecast every other day, rarely get it, until you do and its 4" an hour. – rtaft Feb 28 '22 at 13:52
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    @Harper-ReinstateMonica, "slowed down to 1" sounds like using the "1-gear" on a self-propelled. Your comment makes it sound like you're thinking of a non-self-propelled machine? (The only thing I have *ever* used the throttle for on my machine is to "soft stop" it when I'm done.) I think the equivalent to what you're suggesting is to let it drive forward a little, then back it off / let it clear the intake. (For me, pulling both "turn triggers" while keeping the drive lever engaged will stop it moving and let me pull it back. Other machines may work differently.) – Matthew Feb 28 '22 at 15:46
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    @Matthew Yeah, you're right. Still, it sounds like even 1st gear on the auto-advance is too fast, might need to manual-advance the machine. Could be the snow is too heavy for it. – Harper - Reinstate Monica Mar 01 '22 at 03:11

2 Answers2

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The "right kind of bolt" is a shear bolt.

Specifically, the shear bolt your snowblower manufacturer specifies for that location, since not all shear bolts are the same.

It is deliberately designed to break easily. It's a mechanical fuse. It costs a small amount and prevents breaking other parts that cost a large amount. It is sacrificial protection.

To prevent breakage of the shear bolts, you stop overloading the blower (go slower, take less of a bite, avoid blowing rocks), or you do the classic "replace the shear bolts with regular bolts" and instead of breaking the shear bolts as designed, you break some other more expensive part of the snowblower that the shear bolts were protecting by breaking first.

As mentioned in comments, you might also be seeing a need for lubrication (or adjustments,) lack of which is causing loss of performance and abetting the overload condition. It's also possible (but not the most likely option) that your shear bolts were replaced with incorrect ones that were actually weaker than the correct ones.

Buy lots of shear bolts when buying more. Many recent blowers actually have spots to hold 5-6 spares right on the blower itself - they are meant to be easily replaced. You may have some of the right ones sitting in a bag of maintenance parts included with the blower when you purchased it.

Ecnerwal
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  • All bases covered, OP should accept this answer. – Solar Mike Feb 25 '22 at 10:00
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    @jwh20 While such will prevent shearing, stating something like that here is counterproductive, particularly without *clearly* indicating it's sarcasm and something which will probably cause more harm. Yes, *hopefully* anyone who is reading has read the answer and translated that into an understanding that what you're saying is *exactly* what this answer is saying is a bad idea. However, we all know that people actually understanding the answer and translating that into sufficient understanding to recognize such sarcasm doesn't always happen, particularly when just learning. – Makyen Feb 25 '22 at 14:35
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    Grade 8 bolts would be VERY unlikely to shear. That would solve the problem. It would, obviously, create other problems that will be a LOT more expensive. Yes, it was sarcasm. – jwh20 Feb 25 '22 at 15:02
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    Thank you for a response that puts it all into perspective. Despite 6+ years of snow blowing experience, this is the insight I needed to understand it. – forrest Feb 28 '22 at 02:24
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I have had a few different snow blowers over the past 40+ years and have only broken 6-8 shear bolts. Every time a bolt broke it was from a stone or a piece of hard ice getting stuck in the 1st stage rotor. If you are breaking shear pins and are sure it is not from something getting into the 1st stage rotor then I would try to find a local dealer to have it serviced.

d.george
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