Stump Grinder Help

[catldavis]

Hello All,

I'm a novice and recently purchased a used Dosko Stump Grinder. It's an older model and has been well used. I'm going to be using it personally and maybe for friends. I replaced the motor on it for a lightly used 13hp Honda GX. My question is concerning the front pulley. Once I had it running, I used it to test its effectiveness. During this process, the front pulley came off. I put it back on, but I can't figure out how to tighten the pulley down on the shaft. I tightened the screws as much as possible, but it still slides on and off freely. Maybe it was designed to do so? Does someone know who this pulley is supposed to attach to the shaft? I've attached some pictures so you can see what the pulley looks like. Any help will be greatly appreciated..

 

[RajElectric]

Look carefully at the threaded holes, two should say "on", one would say "off". Tighten the on setscrews only.

 

[catldavis]

Thanks for replying RajElectric. I checked the pulley, it only states "1 3/16", "1910", "Taper" and "Lock" with a circled R indication it is a registered trademark. I see nothing indication an "on" and "off".

 

[67L36Driver]

QD taperlock bushing. Commonly used in industrial applications vrs consumer products.
Designed to squeeze down on the shaft by tightening the 3 cap screws.

Make sure the slit is clear of any debris.

Possibly it has been run loose long enuff the shaft bore is worn out.
Get a new bushing if that is the case.

 

[67L36Driver]

Just examined your pictures more closely.

Try a flat washer under the head of each cap screw.

Industrial supply house/vendor is where to look for a new one.

I hope your shaft isn't hosed.[emoji15]

 

[catldavis]

Thanks 67L36Driver. They're set screws, should they be cap screws?

 

[67L36Driver]

Look carefully at the threaded holes, two should say "on", one would say "off". Tighten the on setscrews only.

Ah, yes!

Take out the screw in the middle. That one is the 'off' position. You don't want to have one in there.

 

[67L36Driver]

No, the two set screws are correct. Just hard for a geezer to see on a iPhone.

Disregard the flat washer comment.

 

[67L36Driver]

Quick Disconnect. Handy for changing the drive ratio between driver and driven shafts.

 

[67L36Driver]

Did you get it healed up?

 

[catldavis]

Thanks for checking with me 67L36Driver. I cleaned out the gap to ensure noting was preventing it from closing. When I was putting the set screws back in, I noticed they were a bit loose when I tried to turn them down. I took it to my local bolt and screw place and they confirmed the threads are shot. They tried a 10mm and it was a little too large. The question to the more experienced, do you think I can tap new threads and it will still work to close the gap? I would prefer not to buy a new insert since once it is put on, it doesn't get taken off very often (if ever). Plus, the grinder won't be used that often.

 

[RajElectric]

Probably will have to replace the entire pulley.

 

[catldavis]

I certainly hope not, I don't even know if I could find one.

 

[RajElectric]

If you have machine shop skills and tools tapping them a larger size is no big deal. A bearing or industrial supply house would have new bushings and sheaves. Even a TSC might.

 

[catldavis]

As I mentioned before, I'm no expert. Since the threads are worn on the pulley side as well as the bushing, will buying another bushing - without pulley - work? I'm just wondering if the lack of threads on the pulley side would still cause the set screw to be too loose and the bushing not to close around the shaft.

 

[RajElectric]

Best bet get a new pulley.

 

[Jim Timber]

Did you get this sorted? You can buy the taper lock center to fit any shaft size in the range. Try Surplus Center or Graingers, maybe McMaster Carr too.