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

SailTrac · Jan 20, 2019

If you look at the owners manual, page 28, reduction box assembly. the sprocket keeps backing off. I have reset the allen set screw as tight as I can but it's not holding. Its done it 3 times in a row. bit of a PITA with this snow storm...
So I know one of you guys will know why it keeps coming loose and what I'm doing wrong.
Thanks,
Mike aka SailTrac

flyerdan · Jan 20, 2019

Without having the diagram to refer to, would it be possible to put a second set screw on top to lock it in? I've seen this done on pulleys where there is enough thread depth.
Another solution might be to replace it with a NAS bolt with a head drilled for safety wire if there is no interference issues.

thepumpguysc · Jan 21, 2019

OR.. a drop of Lock-tite.?? Blue is service removable.. Red takes a torch/heat to remove it & Green is on there.. forget about removing it.

jeff9366 · Jan 21, 2019

thepumpguysc said:
OR.. a drop of Lock-tite.?? Blue is service removable. Red takes a torch/heat to remove it & Green is on there.. forget about removing it.

YES!!!! Have parts grease free before applying thread locker.

John_Mc · Jan 21, 2019

I'll second the recommendation for Loctite or similar thread locker. It's not clear to me what the part is to which you are referring, but I'd be inclined to use the blue loctite (removable). I've had good luck with it, and not having to use a torch to get it apart is a plus, in my book.

SailTrac · Feb 10, 2019

Blue Loctite does keep the set screws in place, however even with Loctite and as much force as I can with the allen wrench, that upper sprocket keeps creeping/walking to the back of the shaft.
This time it threw the key. Luckly I had a 1/4 roll pin that I could jury rig, till I can buy the correct key.
This blower is testing my mechanical skills, and right now it's kicking my butt.

ritschner · Feb 10, 2019

Most set screws have a cup point that locks the set screw in place. Once that gets worn a set screw may no longer hold and needs to be replaced. It seems you may have reached the time to replace the set screw.

dougtrr2 · Feb 11, 2019

Has it always had this issue or is this a recent development? Without a setscrew how is the fit of the sprocket on the shaft? If it is a sloppy fit that could be part of it. Without the key in place I would check to make sure the hole for the setscrew is freely open to the shaft. The thought being the setscrew hole threads might be damaged at the bottom and the screw is bottoming out on damaged threads instead of the key.

Doug in SW IA

Smokeydog · Feb 11, 2019

The setscrews purpose is to increase the friction between the bore and the shaft. Poor fitting or worn parts that move under use defeat the friction. Should be two setscrews at 90 degrees apart. Blue Loctite helps threaded fasteners. There is loctite (660)for retaining press fit parts and worn parts. There are also knurled cup point setscrews that resist backing out. Have come across some soft (counterfeit?) setscrews so make sure using quality ones. Good luck!

bdhsfz6 · Feb 11, 2019

If you are using a simple "L" shaped allen wrench, you may not be able to tighten the setscrew to the proper torque. A set of allen head sockets is better for the job: