Snowblower attachment sprocket problem

[520H4me 0]

I have a 520H with a mid eighties snowthrower single stage blower. The woodruff key falls out because the sprocket woobles on the shaft. I don't know if I need to replace the sprocket, shaft or both. All I know is this is a questionable design. I need to fix it so it is rock solid reliable. Any suggestions?

[MikesRJ 558]

1) First you need to locate a NEW Woodruff key of the appropriate size, in order to do the next steps.

2) Place the Woodruff key into the pocket hole in the shaft, check to see if the pocket hole is worn or damaged relative to the size of the new Woodruff key.

3) Check the width of the key against the Slot in the Sprocket to make sure the slot has not been worn or damaged. Walls and floor of the slot must be flat and square to one another.

In each case above the fit between Woodruff key and the part must be a close-fit (+.005) to slightly snug (-.001). If any of the above tests fail, the associated part must be replaced.

[Forest Road 594]

If that doesn't work . Weld the sprocket to the shaft.

[Shuboxlover 482]

Are there set screws that need to be tightened?? :ychain:

[520H4me 0]

Really wish it was just loose set screws. Tried welding the thing, but my little wire feed Hobart welder does not get enough penetration and the welds just snap.

I wonder if I could put in a new woodruff key - then use a lock collar to butted up against the sprocket to keep the key in place. Worth a shot...

[520H4me 0]

Went to Fleet Farm. They do not have an OEM sproket, but you can purchase a hub and sprocket that will work (you do have to weld the hub to the sprocket yourself). That setup cost around $10. This time I will use Locktight on the set screws so the key doesn't fall out and I should be ok.

[Kelly 1,033]

Those build you own sprockets and pulleys are nice.