Snow BX2750B allen set screw on socket won't stay...

[zzvyb6]

Couple of suggestions:

1) Locate the spot on the shaft where the set-screw lands and grind a flat on it to help it hold position.

2) Instead of an Allen head, find a longer bolt with a square head and use an open end wrench to get it tight.

3) If the sprocket is worn and has a lot of slop or is out of round or the keyway is worn, you need a new part. In fact the old key may have shown you a lot of wear on it. If the sprocket or shaft is worn,wrap some steel shimming on the shaft and pack it tight.

4) Drill the shaft and drive in a hardened slit pin or use a shear bolt.

5) Mark the head position of your Allen head. If it still loosens up, did the head turn or did the base wear ? If the head turned, use a longer bolt and add a locking nut.

 

[CADplans]

Can you install a LOOOOOOONG setscrew that extends out far enough that you can put a lock nut on the setscrew?

I have never seen a setscrew with a nut move,,
the nut can be tightened MUCH tighter with a socket than any setscrew can be tightened.

 

[John_Mc]

I'm not familiar with the sprocket to which you are referring, but be careful about over torquing as well - it might be possible to deform the hub or damage the threads. In addition to the suggestions others have given above, I've seen folks drill a small indentation or pocket in the shaft for the setscrew to sink in to. This can keep the sprocket from walking if for some reason there is not enough friction to do so on the smooth shaft.

 

[SailTrac]

Many thanks to all who responded to a humbled Kubota owner. I've put 500 hours on BX2200 with this blower and 500 hours on my current BX25D. This shows me, I still have stuff to learn.
So, replaced both allen screws twice, the last time with Loctite Blue, not using Loctite was a WTF was I thinking moment. Got the pins replaced, and the key was worn and came flying out in the snow some where, I had moved about 2' into the driveway. Spare key in house or garage, nope. Went to work, they took pity on me and cut me about 15 new keys (we have full machine shop). So new pins, new key, that upper sprocket is on there. We get a foot of snow, its 5:15 am and I ease in the drive and BAM, that's a new sound from the blower. Now some one should be thinking, Mike did you check the chain tension ? Ah no, Mike didn't think too. I go to work and my great neighbor snowblows my drive for me. So I take the blower off, chain on, adjust the chain. Back together and make a few test runs down the driveway, and it throws the chain again. Repeat with again this time apply more force to tighten the chain (5lb sledge). Let the blower run for 15 minutes on 2000rpm to 2,700rpm. I'm out of snow to test on.
So is it fixed ? To be honest, I don't know. Maybe I need a new chain and new upper and lower sprockets , and if I'm ripping it down that far should I be replacing the bushings too ?
This has cost me, new Allen sockets, new tools, worth it. A 50-80k btu propane heater and a new 30gal propane tank. Turn it on, make sure everything is clear 5' in front of it. 30/40 minutes later, you got a nice semi warm garage to be frustrated in.
As I said before, thank you to everyone who responded or just read. Tractor people are the best !
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