Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I just purchased a 2005 Yard Man snow thrower model 31AE5KLF801.  (9.5 HP Tecumseh, two-stage)   Bought it for the trigger steering and the joystick chute control features.

I went to buy some (extra) shear pins today at HD and could only find 4 packs of the shear pins (bolts) for 2004 and older models.  I purchased them anyway assuming the differences were neglible (nut versus cotter pin).  Turns out the 2005 MTD family of brands downsized their shear pins going from 5/16" to 1/4".

They call these new shear pins a "tool less replacement" because instead of a nut, a cotter pin is used.  I'm concerned that these smaller shear pins will be more prone to breakage.  In addition, I have concerns that the shear pin was downsized to protect a gearcase / auger shaft that is weaker than their predessessors.

Are my concerns warranted, or am I overreacting?

Most MTD manufactured snow blowers are purchased on price. So anything they can do to make them cheaper  will increase their market share or improve profits.

But they could change the composition of the shear pin so that there was no oeffective difference.

I dunno about others but I've broken three shear pins in 35 years.

Being in the Tool and Die industry I can tell you that when dealing with shear pins 1\4" and 5\16" dont have the same strength, meaning if you were to use say 1\4' instead of 5\16" or the reverse you will either break it sooner then its supposed to or later and thats where you can have damage prior to the break off. Also keep in mind the groves on the shear pin must line up perfectly with what ever its holding together inorder to protect your gearcase / auger shaft. Another words if the under cut of the pin is not in the proper position it will try to shear on the thicker part and buy that time you'll beat up on the gearcase for sure. Better be safe then Sorry. I hope I'm clear enough.

Thanks for the replies!

My prior snow thrower (if you can call it that) was a 3.5 HP single stage Homelite.  It worked great as long as there was 6- 8" of light snow.  Consequently I never had to deal with shear pins.

I was under the impression that it was "normal" to go through 4-5 shear pins during a typical winter.  Based upon Garandman's comment of going through three in 35 years, I feel that I can now worry about something else ;-).  I will be clearing a paved driveway and sidewalk and typically won't have any foreign objects that might impead the auger.

Thanks Hirschallan for the hint about ensuring that the under cut of the pin is properly positioned.  I would have assumed that if you use the proper shear pins, it would automatically align, but now I'll make it a point of double-checking.

Thanks again!

an interesting concept to consider in the durability and strength of shear pins or bolts, that really makes me think concern of shearing them off is an over reaction in many cases. before i got out of corn farming, we chopped( as well as picked all our own corn,) as well as did alot of custom chopping. for other local farmers. the interesting point on this particular chopper i had, being a 3 row machine with an approximate 300 hp rated v8 diesel, the shear bolt for the chopper knives themselves was a single 1/4 x 20 grade 3 bolt protecting several hundred lbs of flywheel and cutter assembly about 30 inches in diameter. granted we would shear a handfull of bolts during a chopping season, usually due to operator error in getting the header on this machine to low to the ground and feeding a quantity of dirt as well as corn. my point being, turning this kind of weight at several hundred rpms (i dont remember the ratio exactly,  but around 3:1) and based on a 2600 rpm engine speed  the knives are turning at around 850 rpms. thats quite a feat for a single quarter inch bolt.
my guess based on that is a quarter inch shear pin coupled with a 10 horse class piece of equipment should be plenty adiquate and not a big area of concern.