Test for shear bolts/pins? - Snowblower Forum : Snow Blower Forums
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post #1 of 12 Old 09-27-2014, 04:11 PM Thread Starter
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Test for shear bolts/pins?

I have bought shear bolts for my Honda HS928TAS from local power equipment vendors that don't look like OEM and they seem to work OK. I figure that if I have a problem the sellers are local and I can get relief. When they shear they show bright silver metal.

I just bought an Ariens Compact 24 and bought some shear bolts on eBay that were said to be the "Ariens replacement" for my part number. The seller really meant *his* Chinese replacement for Ariens. Since the seller is nowhere near me, a face to face meeting if there is a problem is not possible, so I asked if if there was some test I could do to give me comfort these were shear bolts and not high tensile steel bolts. He just gave me a refund.

I then bought genuine Ariens from Home Depot.

I still have the Chinese bolts, which look beefy compared to the Ariens, with no depression rings cut into them. I put one in a vise and started to pound it with a hammer and cold chisel. I was hoping it would fracture. Instead the chisel dented it rather easily showing a reddish metal under the bright plating.

So, these could be legit and made of soft metal that will shear under load. Is there any test I could give them to be a little more sure -- other than to risk stripping my gearbox?

Ken C
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post #2 of 12 Old 09-27-2014, 11:37 PM
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First off I wouldn't count on getting any relief if your drive fails with the shear pins intact. They should protect in some scenarios abut certain radial loading jams can defeat them and they do nothing to compensate for wear and tear.

As for testing shear pin/bolts do they break and how they break both matter. Evaluating would mean one of 2 things.Getting known correct parts and having a materials lab do a work-up. This would provide data in engineering units. Alternatively you could get relative data by making a jig that mimics the installed pin (shaft & tube) and using a torque wrench to shear the pins.

Unless you want to go into the shear pin business buying a handful of OEM pins is probably your best deal.

Pete
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post #3 of 12 Old 09-28-2014, 07:35 AM
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First off I wouldn't count on getting any relief if your drive fails with the shear pins intact. They should protect in some scenarios abut certain radial loading jams can defeat them and they do nothing to compensate for wear and tear.

As for testing shear pin/bolts do they break and how they break both matter. Evaluating would mean one of 2 things.Getting known correct parts and having a materials lab do a work-up. This would provide data in engineering units. Alternatively you could get relative data by making a jig that mimics the installed pin (shaft & tube) and using a torque wrench to shear the pins.

Unless you want to go into the shear pin business buying a handful of OEM pins is probably your best deal.

Pete
Sometimes I've got a lot of time on my hands so at what point, (specs),
do shear pins break? As we know winter can be long and I do need projects.
I could put my torque wrenches to good use.
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post #4 of 12 Old 09-28-2014, 09:03 AM Thread Starter
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Shear pin specs

This interesting table shows shear pin strength vs diameter and material:
http://www.westernpressure.com/Porta...EAR-VALUES.pdf

This tells me that the grooves cut into the Ariens OEM pins are not just a decoration but are machined to get the material to an appropriate smaller diameter.

Surprising that brass is weaker than aluminum...

Ken C
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post #5 of 12 Old 09-28-2014, 05:27 PM
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Sometimes I've got a lot of time on my hands so at what point, (specs),
do shear pins break? As we know winter can be long and I do need projects.
I could put my torque wrenches to good use.
To understand a given pin I'd want to shear/measure at least half a dozen know OEM samples. Remember that Force is Mass X Velocity so the speed of the wrench will matter. Once you have some numbers you still can't specify anything but you can test substitute candidates.

I can say that I have played around just doing this with a bolt cutter and at least in the case of Gilson the straight clevis style pins are not just plain mild steel like home center round rod. They take a little extra to shear but give a clean break.

Pete
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post #6 of 12 Old 09-28-2014, 05:32 PM
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Originally Posted by cprstn54 View Post
This interesting table shows shear pin strength vs diameter and material:
http://www.westernpressure.com/Porta...EAR-VALUES.pdf

This tells me that the grooves cut into the Ariens OEM pins are not just a decoration but are machined to get the material to an appropriate smaller diameter.

Surprising that brass is weaker than aluminum...

Ken C
In the later years Gilson went from a straight formed clevis style pin to a machined pin with shear grooves. This may have coincided with some value engineering that went on or they just wanted better shear control.

Years ago I designed an industrial machine that need some shear pins. The easy choice was to start with bolts that had known properties and then machine the grooves to get the appropriate cross section for the shear value I needed. Knowing what I wanted for a shear value made it easy. in the case of these OPE projects we can match OEM pins or take a guess.

Pete
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post #7 of 12 Old 11-07-2014, 02:46 PM
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Would anyone care to assist me in obtaining the proper shear pins/bolts for a Toro 724 1980 Snowthrower model #38050. Thank you.
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post #8 of 12 Old 11-07-2014, 03:49 PM
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they do not use shear bolts, they are designed to use standard grade 5 bolts. i have the 824 which is the same machine with a bigger engine and it works the same way
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post #9 of 12 Old 11-26-2014, 11:05 AM
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they do not use shear bolts, they are designed to use standard grade 5 bolts. i have the 824 which is the same machine with a bigger engine and it works the same way
Hi, thanks for your reply! Could ask one more question, what size bolt is this exactly? Would like to pick some up just to have on hand. Thank you
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post #10 of 12 Old 11-26-2014, 11:28 AM
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i honestly dont know, you will never need them because they simply will not shear, they are not meant to
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