Shear bolt madness

[kfeuerherm]

I thought of that. Perhaps with the extension to my dremel. But the trick would be to be sure I've got it aligned correctly... Don't want to make bogus holes in the shaft....

Thanks for the reply!

 

[dsmiley]

How about a little more info? Is this a BX2750D blower? Is the broken shear bolt for the fan or auger? Is the broken bolt an OEM bolt with reduced shank areas at the shear points?

I have sheared a minimum of 15 OEM bolts (5 so far this year) with my BX2750D and have been able to push every shank out with very little effort once I got the holes lined up with the shank. The key is getting them lined up.

 

[kfeuerherm]

I was replying to a thread re BX2750D and specifically to an entry about the pin at the fan, so I didn't repeat that info, but yes, that's the situation.

As for lining them up: 1) I put in a bolt and tapped with a hammer all the way around. As per the post I was replying to I got the impression it lined up when I had the hole in the same orientation as the hole one inch ahead of it (slight catching of my tapping bolt in that position), but it made no difference. No amount of banging made the slightest difference. I find that odd--I've replaced the bolts in the augers a few times with no real problem, which is why I'm stumped... though admittedly it's harder to access here.

I should post a photo I guess but it's dark now and I'm heading on a trip in the morning before it gets light. I was hoping to ponder the problem a few days so I could sort it out when I'm back (on Friday)....

 

[dsmiley]

The two holes in the fan shaft do line up; I replaced one within the last week. I think you should keep trying before drilling.

 

[like2wheel]

Yeah, drilling sounds like a bad idea to me, especially since the pin is a grade 8, & I'm sure the shaft is softer than that.

My fan has a considerable amount of fore & aft play, so in addition to lining it up with the holes on the end of the shaft, I slide it forward & back while tapping on a right angle pointyish thing that I keep for this task. Using something pointy helps so that you dont have to find the exact spot to hit without catching the edges. The sound changes when you find it, then you only need to adjust the fan to let the slug pass out thru the hole.

 

[kfeuerherm]

I forgot to add, in response to the earlier query, that yes it is an OEM bolt. All in all, I seem to be lucky, in the several years that I've run this thing, I've broken maybe 2 or 3 auger bolts, and this is the first time I've broken the fan bolt.

Still... I just can't imagine it ought to be this hard to fix... even if I am doing it in an unprotected area.

I'm leery of the drilling idea too. As I can't be sure I've got it just rightly set, sounds like I could easily compound the problem.

We considered trying to remove the augers, removing the holding clip to slide the fan forward, or trying to access the pin with a longer object through the eject area; but doesn't seem designed for any of those options

Oh, and I did try a narrower object too, like a finishing nail punch. Didn't help.

 

[muskoka kubota guy]

I have a B2920, not sure what the blower model is. I have often struggled getting the sheared fan pin to drop out of the hole. A bushing causes the fan to spring slightly forward and the shaft and fan hole are no longer in perfect alignment. I remove the C clip at the front of the fan and pull the fan fully forward. The sheared pin then drops out. Return the fan to it's location and insert new pin. If the holes are still not perfectly aligned, the new pin can be sharpened slightly. I will be taking the blower fully apart in the summer and make whatever modifications are necessary to stop this problem.

 

[CalG]

The single stage blower on the Bolens HT-23 shears bolts too often. Mostly in early winter before the stones get cleared away.

I purchase a box of 1/4 inch grade 3 bolts and a matching box of nuts every few years.
The shear joint is also a coupling between chain drive shaft and drive gear box. I've put a loveJoy coupling there to provide some shock compliance, It seems to work.

When a bolt shears, It is often difficult to see the hole locations. I like to pull up to the shop door, and grab a heat gun to melt away the snow and ice. That makes observation of the holes much easier. I use a stout taper punch to start driving out the remaining center section of the shear bolt. Then finish with a long straight punch that doesn't bind in the hole.
The new bolt is tapped in, the nut just barely snugged down, then a few quick blows of the hammer upsets the bolt threads so the nut is NEVER coming off. No need of Nylock nuts or any of that ;-)

Warm wet snow is the pits. This recent cold snow has been problem free.. The blower can be pushed into snow until the engine revs drop considerably without shearing the drive. I think about it every time however. ;-)

 

[rbarker]

I forgot to add, in response to the earlier query, that yes it is an OEM bolt. All in all, I seem to be lucky, in the several years that I've run this thing, I've broken maybe 2 or 3 auger bolts, and this is the first time I've broken the fan bolt. Still... I just can't imagine it ought to be this hard to fix... even if I am doing it in an unprotected area. I'm leery of the drilling idea too. As I can't be sure I've got it just rightly set, sounds like I could easily compound the problem. We considered trying to remove the augers, removing the holding clip to slide the fan forward, or trying to access the pin with a longer object through the eject area; but doesn't seem designed for any of those options Oh, and I did try a narrower object too, like a finishing nail punch. Didn't help.

I've broken 3 or 4 of these bolts and from my experience each time is different. I'm not telling you anything you don't already know but the key is getting it lined up correctly. I have a full set of pin punches but I've found ( thanks to someone on this forum) that a 16 penny nail is very effective. The bolt hole DOES line up with the exposed hole in the shaft but there is some play forward and back so the nail helps you to "feel" the end of the pin. Sometimes the end of the broken bolt will leave a burr instead of breaking clean so try pushing it out from both sides. That has been the answer for me on more than one occasion. If you put the PTO in neutral you can spin the whole thing by hand to get better access. (Tractor off please!). It is not a viable choice to try to disassemble the blower to get to the fan drive shaft. I would also never consider drilling!

Let me finish by saying that I have felt your frustration with a stubborn pin on more than one occasion. Patience and perseverance along with moral support from the forum here has gotten me through so far.

Sent from my iPad using TractorByNet

 

[woodchipper]

Good alignment is a must. When you will drive out the brocken pin, and have the new one in place, using a flat chisel, mark both sides with one good strike. This way, next time the pin brakes, and you try to match the holes, they (the both halfs that are now marked in perfect alignment) will align perfectly on the first try. Good luck, and stay warm.