Shear bolt madness

[rbarker]

Reason for shear bolt breakage here in Southern Maine is heavy wet snow and I think the cumulative effect on the strength of the bolt. Additionally, I have a sand/gravel/dirt drive that sometimes has a large stone that gets picked up as well as the occasional tree limb and chunks of ice. Before the ground freezes I plow the snow and get most of the loose stuff out of the way of the blower but there are always a few stones that seem to grow during the winter. Stay safe!

Last year was my first year with the blower and I learned many of the reasons for breaking a shear bolt the hard way, including picking up a loose field stone while clearing the walkway. Not recommended, by the way, makes a heck of a racket! This year I was resolved to put those mistakes behind me and was being real careful (I thought anyways) but I must have hit a chunk of ice buried in the 6" of powder. Guess that's just part of the charm of New England winters.

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[Barneyhunts]

If you look at your pictures you can see the drive shaft between the auger sleeve and the flange mounted bearing. What helps me with my blower is a center punch mark on the drive shaft and a corresponding center punch mark on the auger sleeve when a shear bolt is installed and intact. Then when the bolt shears I line up the punch marks and removal (and installation) is easier.

Okay, I have successfully changed the bolt and am operational again. Thanks to all that replied, every answer was helpful even if to just verify that I was already trying the right things. In the end, the bolt was rounded over on the front side so the advice about rotating it 180 degrees was the key. Even. Then. It took a moderate amount of force to drive it out. I did locate a pin punch but I'm not sure if that factored in at all. Here's some pictures cause I know we all love pictures.



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[rbarker]

If you look at your pictures you can see the drive shaft between the auger sleeve and the flange mounted bearing. What helps me with my blower is a center punch mark on the drive shaft and a corresponding center punch mark on the auger sleeve when a shear bolt is installed and intact. Then when the bolt shears I line up the punch marks and removal (and installation) is easier.

I was trying to think of some way to create an indicator for when this happens and your suggestion sounds like a good solution. Thanks!

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[dsmiley]

I was trying to think of some way to create an indicator for when this happens and your suggestion sounds like a good solution. Thanks!

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Yep. Thank you from me too.

 

[EdenB7610]

Built this for removing the pin in case pin gets frozen. Also acts as the drift pin to line everything up. Welded on 5/16 nut to heavy duty beam clamp, ground out bottom slot for broken piece to drop out.

 

[HillStreet]

After all the reading about shear bolts, I ordered 20 of each today exactly as specified by MK Martin for my Meteor snowblower.

I googled one of the bolts and got to a company called BoltDepot in the Boston area. Prices are from 7 cents to 15 cents each.

There have been a lot of comments about various grades, and bolts that are threaded full length of the bolt. I do not want to substitute from OEM spec so now I have a supply. I have only broken a couple of the impeller bolts and they snapped clean so I will stick to what works.

 

[Dan W]

Good discussion on broken shear bolts, interesting how we all start off the same way
As a key point, we should insure that what ever bolt is installed ( should be no greater than grade 3 bolt) that the shank of the bolt covers both the driven and the drive hole surfaces completely. If bolt thread comes into contact with the holes in the driven component, the threads tend to elongate the hole sooner than the flat shank of the bolt would. I also bought these by the handful early on but now, for the first few snow falls, I set the blower skids lower so as to raise the cutting edge to about one inch high. This leaves a bit of snow which gets packed down over the gravel base and therefore no more blowing stones all over the lawn and no more broken bolts...
Dan

 

[PILOON]

Well, I use grade 5 long enough that there are no threads in the shear area.(threads make for a premature fail point)
Less than grade 5 won't sheer but rather bend+elongate b4 sheering making it hard to drive out with a drift punch.
I have even added a rubber sleeve to my drift punch as in the extreme colds my fingers go numb.
I don't want threads in that sheer area as they simply mess up the cutting action of the shaft to sleeve area. (experience talks)
About the only time I sheer is when a rock gets in there between the flighting and the body or the fan and shroud.

Last winter I sheered maybe twice and both times were due to the city plow inserting a sizable stone into my snow bank. Both stones were sort of tapered but other than a sheer bold no other damage.

 

[kfeuerherm]

Hi Dean,

A tip I learned here on TBN about inserting a new fan pin: If you look at the drive shaft from the front gearbox on the 2750D, you'll see a drilled hole just forward (towards the gearbox) of the fan, maybe an inch or so. The hole for the shear pin is in direct alignment with this drilled hole. So line up the hole for the shear pin fan with this drilled hole and the pin will push right in without trying to spin it around to feel for it.

-PK

Is there a trick to this? I spent several hours, first alone, then with a friend who has several tractors, and we could NOT get the centre part of the broken pin out. We were trying to figure out our best option short of taking the blower off the tractor, because it's really difficult to mount when it's -17C or thereabouts (and no, we don't have a warm garage option of any kind....).

We can get a bit of grip on the hole from one end, but unfortunately it's the end with next to no room to manoeuvre. Pounding a pin through at the other end has accomplished nothing at all

Thanks if anyone has any advice!

 

[Soundguy]

Any room for a drill from one end?