Chipper upgrade

[DeeDubya]

Liberty has replaced their 2-blade flywheel with a 4-blade wheel. I found out when ordering some blades that current chippers are now the 4-blade system. I have to assume that other Jinma knock-offs like Woodmaxx would follow suit.

As you can see 2 blades are set to the outside and 2 to the inside. It must in some way be more efficient. Any thoughts on how this will help? My 2-blade works pretty good but there's always room for improvement.

 

[greg_g]

I wish my Jinma had four. As long as I was turning it with my previous tractor (~45 PTO hp) it would chew up and spit out 6" stuff as advertised. But my new John Deere only has 35 PTO hp, and it's just not enough. So the Jinma has essentially been downgraded to a 4" chipper now, through no fault of its own. I can't help but think however, that 2 extra chipper blades might make up for the lack of input horsepower.

//greg//
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[BethesdaEC]

I wish my Jinma had four. As long as I was turning it with my previous tractor (~45 PTO hp) it would chew up and spit out 6" stuff as advertised. But my new John Deere only has 35 PTO hp, and it's just not enough. So the Jinma has essentially been downgraded to a 4" chipper now, through no fault of its own. I can't help but think however, that 2 extra chipper blades might make up for the lack of input horsepower.

//greg//
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More blades would require more horsepower, every time a blade hits the wood it slows down. With two blades you have 1/2 revolution to catch up, with 4 blades you only have a quarter revolution to restore speed.

 

[greg_g]

Well, your sig line suggests that your experience is with a Wallenstein. My Jinma's got a drum feed with some serious teeth on it. When turning at the proper tractor 540 PTO revs, everything works in harmony. What seems to be happening - after dropping from a 45hp input to a 35 hp input - is that large diameter now bogs down the flywheel, but there's no corresponding slowdown of the feed roller. So as the flywheel slows down, the unrelenting feed roller causes the two blades to start spitting out bigger and bigger chips - to the point where they become chunks.

My thinking is that if there were 4 blades, they'd take twice as many bites per revolution - thereby making up for the fact that there's no meaningful way to sync the feed roller with the flywheel.

//greg//

 

[DeeDubya]

More blades would require more horsepower, every time a blade hits the wood it slows down. With two blades you have 1/2 revolution to catch up, with 4 blades you only have a quarter revolution to restore speed.

That's what I was thinking. My back yard machine is a 16hp DR that will chip up to 4" if I don't feed it too fast. It has only 1 blade and does a pretty good job.

 

[DeeDubya]

More blades would require more horsepower, every time a blade hits the wood it slows down. With two blades you have 1/2 revolution to catch up, with 4 blades you only have a quarter revolution to restore speed.

Another possibility is to slow down the feed system. Just go to TSC and get a larger pulley for the gear box. You might have to also get a slightly longer belt. A slight reduction in the feed system "speed" would hardly be noticable and also give it a little extra torque.

 

[greg_g]

Another possibility is to slow down the feed system. Just go to TSC and get a larger pulley for the gear box.

That might be a good solution for my horsepower downgrade, thanks. But - to slow down the feed drum - the gear reduction box pulley would have to get smaller, not larger. And a larger pulley cannot go on the roller end either, there's barely enough clearance to mount a belt as it is. The positioning of the reduction box is adjustable by the way, so a belt change may not even be necessary.

//greg//

 

[bigtiller]

Liberty has replaced their 2-blade flywheel with a 4-blade wheel. I found out when ordering some blades that current chippers are now the 4-blade system. I have to assume that other Jinma knock-offs like Woodmaxx would follow suit.

As you can see 2 blades are set to the outside and 2 to the inside. It must in some way be more efficient. Any thoughts on how this will help? My 2-blade works pretty good but there's always room for improvement.

I am thinking they just found a less expensive way to do the same thing. 4 short blades doing the same job as 2 long blades.

It also will double the cost of blade sharpening.

 

[KevinMcD]

I have a 6" chipper I bought from TSC (I forget the brand name but it is a Jinma painted yellow) with 2 cutting blades. I have a 30HP Kioti and the chipper seems to work fine. It seems to handle 6" soft wood without problem. The problem with my chipper is that the shaft moves on the pillow block and ultimately causes the flywheel and blades to hit the housing. I like the design but the quality control is terrible.

 

[nuffer460]

I am not sure that I understand the horsepower issue. I have a Jinma 6" chipper from Ranchhand. Ronald and his crew set it up. I have a NorTrac 254 ( Jinma ) Tractor. It can and has on more then one time chewed up 6" logs of various tree types. It pulls the engine down some, but isn't close to stalling the engine. Is there that much power lost at the pto with hydraustat drive tractors.

 

[Baby Grand]

Looks to me like 4, short, staggered blades instead of 2 long sets of 2 blades. 4 small slots = stronger wheel than 2 long slots. I see they also welded a circumferential gusset at the tip of the blower fins = much less tip bending & fillet weld stresses. Also, more mass at the OD = greater rotational inertia. I don't think the staggered blades require any more power to drive than the in-line blades as they are taking smaller bites more frequently? Seems to me like all the changes are going in the direction of better performance & durability. I am shocked!

 

[Dr_Zinj]

Guess I'm just weird.

Anything more than 2 inches in diameter I call firewood.