Key in snowblower shaft

[JoeB 15]

I'm having trouble keeping the key in my snowblower shaft in place.  There are two set screws which I made as tight as I could, but when I hit a clump of wet snow, I loose the key.  Any recommendations.

 

thanks and Merry Christmas to all.

[gwest_ca-(File Mod) 11,037]

Where is it located?

 

[JoeB 15]

It keeps the main drive pulley, perhaps number 12 in your diagram, from rotating on the main shaft of the snowblower.  It is a single stage blower that came with the C-120 I bought a few years ago. I don't see the key in your diagram.

[wallfish 16,992]

"Loose the key" as in it's shearing off or it's going missing?

If the keyways in the pulley and or the shaft are still good, get new set screws. They are hardened and cupped on the end and designed to dig in when tightened.

[adsm08 2,036]

6 minutes ago, JoeB said:

It keeps the main drive pulley, perhaps number 12 in your diagram, from rotating on the main shaft of the snowblower.  It is a single stage blower that came with the C-120 I bought a few years ago. I don't see the key in your diagram.

 

If the pulley in question is #12, then the woodruff key should be parts #42.

[JoeB 15]

It just goes missing.  How do I know if the keyways in the pulley and the shaft are good.  I had to file slightly the keyway on the shaft because some metal at the top edge had sheared probably because of the pulley rotating on the shaft.  I was able to tap the key into the shaft keyway and slide the pulley on.  Perhaps I didn't tighten the set screw enough.  I did notice they were duped at the bottom.  One of them is somewhat rusted so may not tighten enough.

I am wondering how you know if the keyways are ok.  Also where can I buy new set screws that are hardened and cupped?

 

Thanks for everyone's comments. 

[peter lena 8,592]

JOEB , in addition to new set screws , I would run a bottom tap thru any related holes to insure your set screw is bottoming out , had a similar  issue on a blower , and there was a wall of rust at the bottom of the set screw hole , preventing it from doing its job, also lubricated screw to insure its total pass on threads , pete

[JoeB 15]

Pete, I wondered that myself.  When I tried to screw the set screw in without the shaft, it got stuck, so I suspect you are spot on.  thanks.

[1995 520H+96+97 937]

Or maybe their is another set screw, two in one hole.

[Shynon 7,459]

53 minutes ago, 1995 520H+96+97 said:

Or maybe their is another set screw, two in one hole.

[JoeB 15]

Hello,

I thought I would send and update.  I tried what was suggested.  I did need a tap to clear the gunk at the bottom of the hole.  I got some new case hardened set screws, but not to much luck after about 45 minutes the screws worked loose.  I thought of getting some lock tight but decided instead on brute force.  I got a couple of hex head bolts and nuts.  I put the nuts on the bolts, then used the bolts instead of the set screws and tightened the nuts against the hub to look the bolts in place.  So far so good.  Any thoughts.

 

best,

 

joe

 

[lynnmor 7,302]

1 hour ago, JoeB said:

I got some new case hardened set screws, but not to much luck after about 45 minutes the screws worked loose.

joe

 

 

My guess is that the shaft and/or the pulley is worn to a very poor fit.  Do you have one set screw that is on the key and another that is about 90 degrees away?

[JoeB 15]

Yes, the pulley is quite loose on the shaft.  There is a second set screw as you described.  I don't think there is anything I can do to reduce the loiosness of the pulley on the shaft, but I am open to suggestions.  I don't know which part is worn, could be both so I don't think simply replacing the pulley would help.

 

thanx 

[wallfish 16,992]

Scroll through this this link. You can order the 3/4 keyed shafting, key stock, pulley, sprockets, bearings, chain, V-belt and everything you need to rebuild the blower's entire drive line. Just need to cut the keyed shaft and key stock to length.

https://www.surpluscenter.com/Power-Transmission/

[lynnmor 7,302]

10 hours ago, JoeB said:

 I don't know which part is worn, could be both so I don't think simply replacing the pulley would help.

 

 

Measure them, if you have no tools to measure, you should get them.   A simple incomplete check would be to clean the shaft of rust and paint, then slide the pulley in to an unused place to check the fit there.