Quote:
Originally Posted by cnysabo
Hi MWShaw,
I just stumbled on your thread because I have been getting somewhat frustrated with shearing bolts on my snow thrower. I have a H48 mounted on a 1641. And unfortunately I regularly snap bolts. I use the regular grade 2 bolts and lock-nuts and sometimes I am good for a half hour, other times about 5 minutes. When I bought the thrower, I don't know if I even had a true shear pin in it. I am tempted to use a grade 5 bolt because I spend more time crawling around changing the bolts than anything else. I also do not snug the nut up tight, just far enough on the nylon to keep it from backing out. I have rad that slop will shear the pin quickly too... Anyway, what caught my eye about your post is that I also replace the bolts at the gear box end of the arm. And I am missing the Parallel Key on mine too. But I am not sure why it's not 6 of one and half a dozen of the other? I find it easier access the gear box end then the end of the arm under the shield. Do you know if I am sabotaging the set up by making the weakest link by the gear box? Also I noticed in the picture of your actual shear pins, they seem to be clevice pins, without any groove etched into them. I can actually get some of those at Lowes, is that a type of shear pin I should perhaps be using? When this system works, it's great. But when it fails without a consistent pattern, then it is frustrating. Anyway, I will keep reading what gets posted. thanks.
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Seeing as how the skematic images I posted, are supposed to be for the H42 and the H48, I would think you should have the 3/16 key at the spocket end also? Funny thing, mine has a 3/8-16 set screw drilled and tapped, right above the key on the sprocket end of the driveshaft. (It is not shown in the skematic?)I guess maybe it's some a previous owner added, but why is the jam nut on that backing off also?
From looking at the skematic, I believe the design intent was for the weak link to be the shear pin at the gearbox.
The picture of my shear pins, is the ones that my Cub dealer sold me. I believe those are the #12 in the skematic pictures.
Yes it is a great system, but I'm getting very frustrated with it. I thought I was making a step up from my QA36A, but I never had this much trouble with that one.
Speaking of the QA36A, mine had no shear pins that I am aware of. The weak link on that was the belt, if it plugged with snow or caught the impleller on something, the belt would slip.
So that may be what I do with this one, use grade 8 cap screws instead of shear pins, add a few 3/8-16 set screws to each end of the driveshaft and let the belt be the weak link?