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9560 concave adjustment

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4.8K views 16 replies 7 participants last post by  twinstacks  
#1 ·
Is it just our combine or does all the 9560/40 560/40 combines concave only close down to .47” when it’s right closed?
If that is as closed as it goes from factory has anyone made some adjustments to make it close all the way to 0? Sucks trying to thrash a thin wheat crop and can’t close the concave tight enough to grind all the heads out.
Our old whites you could set it so the rub bars would just tik on the concaves then back the Handel off a 1/4 tune and didn’t matter how light of a crop could still get the heads all thrashed.
 
#3 ·
it's hard to get the idea of grain on grain thrashing but this is how the new systems work.the elements on the rotor are used to move the grain around and over the concaves.the more time it can be held and rubbed on the concaves the more it will be thrashed.this year made it very tough to do a real good job with so little bulk entering the rotor. on the other hand was short dead ripe barley that completely exploded after hitting the accel beater and caused an over thrash overload on the sieves.give me long tough straw any day at least you can set everthing to do it's designed job.a thin short crop of hard thrash wheat would even be a struggle for the old 860 with zero concave and 5 filler bars.
 
#4 ·
Ya I’m familiar with the grain on grain thrashing just hard to do with a light crop.
So trying something new with concave setup this year after listening to other guys that have used these machines longer than me.
Front 2 concaves are blanked off
Middle 2 are normal small no blanks
Rear 2 are small wire with every other wire removed. Put all 6 disrupter bars in
Once we get going I’ll try and let you all know how it works.
 
#7 ·
As for zero clearance, consider how much space there is between the rub bars and the rotor body. Seems like in modern rotor designs the rub bars are mostly there to move the crop past the concaves where they grind from a combination of centrifugal force and the sideways motion, not to grind the material against the concaves directly between the rub bars and the concave. There's really nothing to keep the crop between the rub bars and the concaves, so no matter how close you run them, it's not likely to do much direct grinding. I suspect this would be even worse in very thin crops.

We've typically been harvesting alfalfa seed with the concaves set to zero on our particularly-branded red machines (and we can get them to actually touch of we want to), but this year I'm going to try opening the concaves wider. That should slow the material down (a tighter concave usually speeds up material flow all else being equal), and get better threshing and separating.

Massey's long straight bars might be a slightly different story, though, and obviously conventional wisdom doesn't apply in extreme conditions.