Help with chipper blade adjustment.

[SPYDERLK]

Ok, I can't take it anymore. Could someone explain the logic around the anvil blade gap? I keep reading two different numbers with about a 10x difference. The first gap seems to be in the shavings range (0.015"-0.035"). The second gap is in the chipping range (0.25"-0.30"). I haven't adjusted the anvils on my JM-6 and they're set at .25" and they seem to work just fine.

Is this just a preference on the finished product? Nice smooth shavings vs. course chip? Smaller shavings have more surface area...dry faster...are easier on the feet of livestock?

I can't imagine it's a performance thing, considering that a 0.025" gap would need to make 10 cuts to equal the volume of 1 cut at a 0.25"

Am I just missing something here?

Thanks in advance,

-Steve

Steve, Its easy to miss, but the anvil actually serves little function other than supporting the log while the cutter chops it. The feed drum pushes the log tip to the cutter blades and the angle on them helps drag it on in as they cut. I tried the small gap specified. Chips arent much different, but I dont think it feeds as well that way. I have mine set at about 1/8". Youre right tho, it did work OK at 1/4". Im worried that is too much overhang tho.
larry

 

[JerryK]

The wood is being cut several inches from the anvil, and the size of chip is more related to feed rate and rotation speed of the cutting knives. If you set the gap too wide at the anvil, it puts too much stress between the knife and the anvil as the knife passes. You want the knife to cleanly 'cut' the wood in this area, and not just jamb wood past the anvil. So set the knives to the .015"-.035" value. [sound OK??]

 

[srjones]

Ah...ok, I get it now.

 

[wedge40]

It took me a while to grasp this as well. I think I have it now. The gap has little to do with the chip size. (at least that's what I think), it has more to do with weather the wood is cut or crushed. I think of the anvil/blade combo like a set of pruning shears. If the gap between the two is large it will still work, but more difficult to use, not to mention the extra stress because of twisting.
To change the chip size significantly you would have to vary the feed rate. Since we have a feed roller the only option is to change to pto speed.

To the experts out there.. Am I way off base here or close.
Also I'm pretty amazed that vibrations from the flywheel and rest of the machine that the distance between the blade and anvil wouldn't change by more that 0.010".

Wedge

 

[wedge40]

**** I should have taken that speed typing class. JerryK and Spyderlk already said the same thing.

Wedge

 

[SPYDERLK]

To change the chip size significantly you would have to vary the feed rate. Since we have a feed roller the only option is to change to pto speed.

[[[To the experts out there.. Am I way off base here or close.]]]
Also I'm pretty amazed that vibrations from the flywheel and rest of the machine that the distance between the blade and anvil wouldn't change by more that 0.010".

Wedge

[[[Only just a little.]]] Thinking about it and observing more myself, I see that the knives only stick out a certain amount proud of the face of the flywheel. So extra feed beyond that distance per 1/2 revolution would just come up short against the flat face of the flyweel until the knife chops it. I think the only way to get much larger chip would be to space/shim the knives out further. A little would go a long way and Im guessing the integrity of the machine would not support an additional spacing above about 1mm. I may try this. I so, I will report back.
Im with you on flex in the system being greater than 0.010". I would never want to see the knives running that close to the anvil. I believe [and have found] that larger distance does not cause a problem. I use about 0.100" eyeballed. This leaves the anvil further back and more well supported. The log overhangs more to get to the knives and so jumps a little more in response to the blows. I thinks this aids the feed.
Take care to tighten all bolts and set screws, esp those big high grade bolts on the pillow blocks that hold the flywheel shaft.
larry

 

[wedge40]

Well after much trial and error I think I have the knives set at about 0.035". I was using three "cards" stacked.. but I lost one down inside. If it wouldn't have been for that I would have been around 0.050".
I still have to adjust the pulleys tomorrow and the I might be able to fire the thing up.

Doing all this by yourself can be a real challenge.. I had to make an extension for my wrench. (1/2" pipe and hose clamps) so I could reach the anvil nuts while holding the hex wrench. I did what someone had suggested and too the feed roller off. When I put it all back together I put lots of grease on everything that moved.

Sure hope the pulleys are easier to align..

Wedge

 

[wedge40]

I went out to adjust the pulleys this afternoon and I'm having a hard time figuring out how to loosen the belts and which pulley I should be moving. I'm guessing the bottom one (bigger one) would be the one I would have to adjust.
Before I went too far I decided to measure the alignment with some feeler gauges. The pulley's are only out by about 0.018". For now that's close enough.

There are two bolts (one on each side) way toward the back of the chute and up about 8". Are these just stops for the feed roller from riding up too far? I found that I can't get grease to the pillow bearings. The grease zerts are too small. I'm missing one and will have to find a replacement.

Well time to see if I have gas and a short enough upper link.

Wedge

 

[wedge40]

Bubble this back to the top of the list.

Tractor was giving me some fits so today was the first time I could get the chipper hooked up and running.
I'm going to take the base off and add some 4x4 to lift it up a little and also to stabilize the chipper. My upper link needed to be between 28" and 32". A lot longer than I expected. I took awhile to get the pto shaft hooked up, but I'm sure if I put it on in the correct order I'll be fine.

Does anybody know of way to keep the two halves of the pto shaft from separating?

I did try a few branches, but they were pretty wet so not much of test. The wet wood didn't make much noise, but when I "really" start to use I'll get my ear muffs out.

I want to thank all those who posted suggestion or helped answer question and were patient with me.

I'll get the camera out and take some action shot and put that into a new post here.

Wedge

 

[srjones]

Bubble this back to the top of the list.
....
I'm going to take the base off and add some 4x4 to lift it up a little and also to stabilize the chipper. My upper link needed to be between 28" and 32". A lot longer than I expected. I took awhile to get the pto shaft hooked up, but I'm sure if I put it on in the correct order I'll be fine.

Does anybody know of way to keep the two halves of the pto shaft from separating?
....

Wedge

Wedge,

Take a look at the pictures I posted at the end of this thread. http://www.tractorbynet.com/forums/customization/94037-modifications-jinma-chipper-2.html

Instead of 4x4s you might consider pressure treated 4x6s. The way I did it, you don't need to remove the base.

About the PTO shaft...the one that came with the unit smaller than I would have expected. And, since I wanted to use my quickhitch, I needed extend the lower arms so by that time the two halves of the PTO didn't even meet. So, I could get a longer shaft (which I plan to), or I could not use the quick hitch or I just get a PTO shaft extender (which I did).

Good luck,

-Steve