# Breaking shear pins



## DonnieBoston (Feb 11, 2017)

Just about every time I use my snowblower I end up breaking a shear pin. I know objects do cause them to break, however my question is can a shear pin break because it is on too tightly? Should they be put on loose enough so they can turn? 

Thanks!


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## Nshusky (Jan 1, 2017)

DonnieBoston said:


> Just about every time I use my snowblower I end up breaking a shear pin. I know objects do cause them to break, however my question is can a shear pin break because it is on too tightly? Should they be put on loose enough so they can turn?
> 
> Thanks!


If the shear pin is he type with a nylock nut then I just tighten until it meets the shaft and no tighter. It will not back off.

I have heard that tightening the nut too much can indeed cause some binding (on certain models of blowers) and then the pins snap under lighter stress than designed for.

Some blowers have shear pins that do not have a nut but a bow tie style cotter pin. This allows the shear pin to have a little play and prevent over tightening.


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## all3939 (Dec 21, 2014)

For one make sure you use OEM pins and not some other brand. Also tighten to the point where it doesn't rotate and then back it off so slightly that it rotates by hand. There has been instances when the OP snugged it to the point where when the auger had to shear the pin it could not spin free of the shaft and took out the gear case.


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## JLawrence08648 (Jan 15, 2017)

I follow all3939 method, tighten until it touches then back off slightly so it easily turns. I get my shear pins from Amazon. I've bought different ones but generally Stens because of their name. The pin has to be unrated and grooved. The groove has to fit at edge of the auger hole, if too long a pin, the groove won't be in the right spot to break.


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## rnlocnil (Feb 9, 2014)

I have an Ariens Sno Thro Compact 24 LE model 920014 Serial number is 135272

The original shear pins lasted since 2013, but since Thursday, I've broken 3. The first one went within a couple of minutes of snow blowing. The second maybe three minutes after that. I replaced both with the pins that come with the snowblower. I kind of guessed on the torque, but I think it was probably between 6 and 12 ft lbs as per the manual. If anything, a bit looser. Are they supposed to seem a bit loose, at least in the shaft? I guess next time I'll leave them just the tiniest bit loose. 

Anyone have suggestions as to why the machine suddenly eats shear pins? It's not like I haven't encountered bits of wood and pavement before.

Is it a special phenomenon inside Route 128? ;-)


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## RedOctobyr (Mar 2, 2014)

Maybe the current shear pins are a bit softer than the ones that were originally installed, for whatever reason? 

I have broken a couple seemingly at-random. I've driven into deep, dense snowbanks/EOD, even icy, without breaking anything. But twice, I've broken a pin for reasons I can't explain. I didn't see anything get ingested, and I didn't hear anything. I was just clearing normal snow in my driveway, then noticed that it was "plowing", and figured out that a pin had broken.


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## Dauntae (Nov 10, 2016)

rnlocnil said:


> I have an Ariens Sno Thro Compact 24 LE model 920014 Serial number is 135272
> 
> The original shear pins lasted since 2013, but since Thursday, I've broken 3. The first one went within a couple of minutes of snow blowing. The second maybe three minutes after that. I replaced both with the pins that come with the snowblower. I kind of guessed on the torque, but I think it was probably between 6 and 12 ft lbs as per the manual. If anything, a bit looser. Are they supposed to seem a bit loose, at least in the shaft? I guess next time I'll leave them just the tiniest bit loose.
> 
> ...


A friend of mine has the same compact 24LE and there having the same issue, it's to the point his wife is having me fix there old MTD because they are so sick of changing pins, hope it gets figured out.


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## 524SWE (Jan 20, 2017)

my shear pins look like this, use them on my Cub Cadet, fit lots of different machines, can be bought many places, fit loose, makes it easy to check rakes haven't rusted to shaft too


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## rnlocnil (Feb 9, 2014)

RedOctobyr said:


> Maybe the current shear pins are a bit softer than the ones that were originally installed, for whatever reason?
> 
> snip


The pins that broke all came with the snowblower. The first two replacements were the ones that came with it, in the clips on top of the gadget that turns the chute. So it's likely that they're exactly the same. I think the problem may be that I tried to torque to the instructions, i.e. 5.8 to 12.2 ft-lbs. I loosened the remaining pin until it just barely moved, and installed a replacement I found locally, also just slightly loose. It's been good for an hour so far. 

Now I have a dozen replacements available, so there's no more point in my snowblower breaking pins than there is in it raining when I have an umbrella. ;-) I'm probably safe for the "life" of the snowblower.


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## wow08816 (Feb 2, 2017)

I went thru a streak where I was breaking shear pins one after another blowing 16" deep soft snow. When did it stop? When I ran out of shear pins. So I did the unthinkable and used a zinc bolt to get the job done. I would not recommend anybody doing what I did in my moment of desperation. The next day I secured more shear pins from my local Sears store and switched out the bolt for a proper shear pin. Haven't had a shear pin break since. My guess was that I had a bad batch of shear pins. I tighten my shear pins to the point that there is no play.


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## djc11369 (Feb 17, 2014)

wow08816 said:


> My guess was that I had a bad batch of shear pins.


This is what I suspect when I read someone is going through a lot of shear pins. Who knows what material spec. some of these pins are made to coming from China. I doubt anyone actually tests a lot when they receive them for material properties and only do the basic measurement checks. Just because you supply a spec. drawing or buy based on specs. doesn't mean that's what you're actually getting without verifying. I know I've gotten bolts supplied with products that indicated grade 2 that in no way were what they claimed to be.


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## rnlocnil (Feb 9, 2014)

The guy at the store I bought the shear pins told me he once used coat hangar wire in desperation. That's probably a lot safer for the machine, though his was a Craftsman (or a Sears?) and used 4 pins, so the load may have been lower.. Or when you say "zinc bolt", do you mean that literally, rather than a zinc plated bolt? I suppose aluminum ones might work okay too.


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## chrisexv6 (Feb 4, 2014)

In a real pinch I used a short length of threaded rod and ground notches into it where they would line up with the outer edges of the auger.

I figured the all thread wouldnt be as strong as a real shear pin and Id rather have it break earlier (and make more) than not break at all and potentially kill my gearbox.

Since then Ive ordered about 30 shear pins and I have them stashed at various places around my home


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## RedOctobyr (Mar 2, 2014)

chrisexv6 said:


> Since then Ive ordered about 30 shear pins and I have them stashed at various places around my home


Yeah, I have a bunch of spares at the moment, I'm too chicken to let myself get down to 1 spare pin or something. And I know where I keep them, but I should look at my machine to see if there's a good place that I could store one or two directly on the blower. Just so that if my box of blower parts ever got temporarily misplaced, I'd at least know I'd always have a few pins available.


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## rnlocnil (Feb 9, 2014)

Of course, after I had a dozen shear pins available, none broke for quite a while. Now that I can't remember where the extras are, I broke one, so I only have one left of the two that were in that clip on the blower in reserve. Sigh.


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## peterk (Apr 30, 2014)

DO NOT TIGHTEN THEM! They are 5/16" cut down to 1/4" where they should shear. Your rakes should move on the shear pin. If they break in use, you are asking the machine to do more than it was made for. Can I say ice! They are used to protect the gearbox.


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## LenD (Nov 17, 2020)

OP asked that question over 4 yr ago and has not been back since 😉


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## JLawrence08648 (Jan 15, 2017)

peterk said:


> DO NOT TIGHTEN THEM! They are 5/16" cut down to 1/4" where they should shear. Your rakes should move on the shear pin. If they break in use, you are asking the machine to do more than it was made for. Can I say ice! They are used to protect the gearbox.


Peter is correct, do not tighten shear pins. When you tighten them you stretch the metal ever so little making them more susceptible to snapping. I tighten them until they spin but against the auger, if I've tighten them where I can barely turn with my hand I then back off until they spin.


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