8" No-Name Chinese Chipper Grief and Slip Clutch

[mikester]

The chipper flywheel was stopping and the engine wasn't bogging down...

I discovered that the secondary pulley driving the flywheel was spinning on the shaft. I assumed that the shaft key either fell out or disintegrated based on the metallic dust on the inside of the pulley. Looking at the parts diagram it doesn't show a key for the secondary pulley and it got me wondering if

1. the pulley designed to slip on the shaft as some sort of chinese safety feature?
2. somebody forgot to put the key into the drawing and the pulley was assembled without a key and retaining set-screw

The shaft is scored badly and has some evidence of bluing and the pulley hub is scored on the inside as well. There is no slop on the hub over the shaft. This is a no-name chinesium chipper with questionable build quality. Everything looks hand made - eg. the spare chipper blades are about 1/16" to 1/32" difference in length.

Ideally I would replace the shaft and hub but good luck finding parts that fit. I am not keen on disassembling everything and getting a machine shop to fabricate a new flywheel shaft.

My questions to the group:
1. Would you consider simply hammering the hub back onto the shaft with a key and set-screw and hope for the best?
2. Would you pull the shaft and have a machine shop fabricate a new one?

In either case I think I should be adding a slip clutch as a minimum. I've seen some viscous PTO couplers in the past but for the life of me I can't find anything useful on google search results. Does anyone here have something they'd recommend for my chipper application?

I figure the failure mode would be the shaft end holding the pulley would most likely shear off. The last thing I want to see is the 200 lbs flywheel suddenly stopping and destroying my tractor PTO.

 

[oldballs]

That must be some large chipper with a 200 lb flywheel....must be a commercial unit beyond my experience.

But good luck anyway.
Mike

 

[sea2summit]

Could you get a machine shop to drill the shaft and pully for a shear bolt? They may have a magnetic drill press that could finagle a way in so you don't have to completely disassemble to the shaft. On the other hand, if the pully slid off without retention how hard could it really be to pull the shaft completely

 

[Tinhack]

Is it a tapered hub pulley? I can't imagine a driving shaft without a keyway. No set screw is going to drive a 200lb. flywheel. I suspect a sheer bolt won't either. Since you didn't post the parts drawing or any pics, it's hard to suggest a fix other than welding. Good luck.

 

[mikester]

Is it a tapered hub pulley? I can't imagine a driving shaft without a keyway. No set screw is going to drive a 200lb. flywheel. I suspect a sheer bolt won't either. Since you didn't post the parts drawing or any pics, it's hard to suggest a fix other than welding. Good luck.

Yes there's a tapered hub [12] that fits on the straight shaft [5], the pulley [13] is also tapered and fits on the hub. Pulley uses 5 belts.

The shaft [5] and hub [12] have a 1/2" keyway. The hub [5] also has a provision for a 6mm set screw to lock the key in place. I found it weird to see no key and no set screw on the chipper or in the drawing. Either the set screw wiggled out and then the key, or more likely, the manufacturer was saving money and never installed one.

The main pulley and drive shaft [17] connected to the PTO have a key in place [24] in real and in the drawing.

 

[mikester]

Could you get a machine shop to drill the shaft and pully for a shear bolt? They may have a magnetic drill press that could finagle a way in so you don't have to completely disassemble to the shaft. On the other hand, if the pully slid off without retention how hard could it really be to pull the shaft completely

Trust me, I'd have to completely disassemble the machine to remove the pulley and fan assembly as the manufacturers were kind enough to make the fan shroud interior and fan inaccessible. The hub was spinning on the shaft and it was an SOB to remove the pulley due to lack of clearances between the hub and frame. The drawings and the as-built machine casually resemble each other. My impression of the build quality is that every machine is custom built one at a time by drunk workers using hand files on coat hangers for welding rod.

At least it has a cast 200 lbs fly wheel!

 

[arto98607]

That looks very similar as design of my US made S&R Pro Chipper, as well as the old Machete chipper.
S&R Industries has closed their doors long ago I think...

I bought my S&R Pro Chip used in the 90's and it still works pretty good for us, but of course it would be nice to have adjustable speed hydraulic feed roller drive, instead of the original fixed speed mechanical feed.




Sounds like the key was left out of your Chinese version chipper!

PS.
I saw similar copies for sale locally for just over $1000 few years ago.

This is a photo taken around year 2000

 

[arto98607]

Here is another S&R that was offered for sale locally when I was still looking around.

And here is the original design Machete chipper:

 

[mikester]

I think all these units started with one general set of plans that have been modified depending on the manufacturer's capabilities.

I ended up ditching the mechanical feeder and installing a reversible hydraulic in-feed motor with speed control. Chips bouncing out of the chute would de-rail the mechanical feeder belt. The original PTO shaft to the feeder drum looked like it was butchered from a cheap socket set 1/2" swivels. POS all around, I will never buy any equipment made in china ever again. Getting harder to do these days....

 

[5030]

The first parts drawing looked to be a Jinma (I had one) and sold it after 3 years for more than I paid for it. Now, I pile it up and roast all of it. Much easier. Little accelerant and a match is all that is required.