Chipper Bearcat 70554 shredder knife replacement. Knife shaft stuck.

[kauaijohn]

I need to flip the shredder knives on my chipper/shredder. A bear cat 70554 (PTO)

I've replaced the chipper blades many times and have adjusted and replaced the belts so I have some experience with the machine.

However, I'm having no luck at all following Section 5.4 of the user manual "Replacing the shredder knives."

I was able to remove the #10-24 bolts. I am unable to get the shredder shaft to move.

The manual says "remove the rear side access cover".
The manual also says, "Using a hammer and punch, drive the knife shaft through the access hole on the rear of the machine."

My confusion comes from there being no "front" in the instructions. There is a 5/16" hole on the side opposite the side that has the access cover. Am I suppose to use the punch through this hole and drive the shaft out the rear or am I suppose to use the punch and drive the shaft through the 3/8" hole. (While it seems "obvious" that I should put the punch into the hole in the front and drive the shaft out the access port, the lack of success prompts me to ask this stupid question.)

I was using a 1/4" pin punch and I've tried hammering on both sides. The knife shaft isn't moving at all. In fact, I managed to destroy the pin punch. (bent it) So I am using "some" force but I wouldn't call it "considerable".

The shaft appears to be 3/8" in diameter. (it is actually slightly less)

These blades have not been swapped in 4 years. I've used liquid wrench on all the spacers in an attempt to loosen them. (FWIW, If I grab a spacer with a vice grip and try to rotate it, it does not move.) The shredder knives rotate freely (save for one) because I've used a lot of lithium grease on them.

Do I need a bigger hammer?

Thanks

 

[gwdixon]

Here is a photo of the inside.

Just from a cursory view of the photo I don't see the access hole on the "front" (left) of the chipper. I'm guessing that the access plate for the blades is called the "rear" of the chipper. From your description, the shaft should likely be driven out through the access plate area. But apparently none of the shafts will move.

My guess is that the spacers are going to have to turn to get the shaft out. They are probably gummed up something awful depending what has been put though the machine over the four years.

Try soaking a shaft with Ed's Red [equal parts transmission fluid, acetone, and a solvent (like diesel or mineral spirits)] to see if that works. Put a vice grip or pipe wrench on the spacers to twist them and loosen them up. Otherwise, you are SOL.

 

[kauaijohn]

Thanks!

FWIW: I took the same photo you did. The hole on the left side doesn't show up because it is behind the flywheel.

I needed someone to confirm that I wasn't doing something stupid.

I'm not looking forward to getting Ed's Red all over the garage floor, but gotta do something. Maybe buy a new chipper? ;-)

 

[bob 59912]

You need a bigger hammer. I bought my Echo Bear Cat shredder/chipper used. It had been stored outside and the shaft and spacers had rusted together in places as well as the shaft to the rotor. After some PB blaster, a 10" long 3/8" bolt works well at driving out the rusty shafts. It has been a while so I may have drilled out the hole that you say is roughly 5/16".

A 2x6 inserted under the rotor / shredder blades and the housing will help to immobilize the rotor, so you can twist on the spacers, if needed.

After removal the shafts can be cleaned up by chucking them in a drill press and using 150 grit wet dry paper. The inside of the spacers can be cleaned in a similar way, by taping the same abrasive to a 1/4 rod and wrapping the wet dry paper around it and chucking the rod in the drill. After this, when reassembling the spacers slide easily on the shaft and the shaft slides easily on to the rotor.

 

[kauaijohn]

Thanks Bob. The photo was very helpful. It confirmed what I thought was right.

 

[gwdixon]

bob 59912 has valuable experience to share. He deserves a "thanks" for posting.

But the dilemma remains about the removal of the shafts. It came to me in the middle of the night that heat may work on loosening the spacers. Once the spacers spin on the shafts then the process is well on the way to success.

A propane torch should be enough. The problem is that a chipper has fuel in the form of wood chips and wood dust. The interior would have to be quite clean to safely use heat.

 

[kauaijohn]

Thanks GW.

I think I'll avoid using heat after all the chemicals I've put on. But if they don't work, I'll move the chipper out of the barn.

 

[10backacres]

Aloha
I've had a 70554 since 1994 (single edged blades) I turned shred knives 1 time. I've just used a 1.5 inch cut off wheel with the locking shaft on the dremel to touch up the edges of the knives rather than spending $400 for new ones. Don't take this advice literally since if you grind too much off and unbalance the 36 knives on the drum it can be a safety issue. I change the knife blade 5/16 gr 8 bolts every 3rd time since I learned the hard way they don't last forever; I had 2 blades come off and break apart $130 gone. I tried the 5/16 thick generic blades resetting the clearance to the anvil. Make thicker chips & more load on the tractor. Currently looking at another used later model.
Steve