715 grinding corn

[steve in wi]

I have a 715 and when I did beans last year worked great,very
good threshing of the pods well this year I went to switch the
concave over,lower it,I did what the book said 7/8 to one
inch.one inch is where it stopped moving anyways.cyl speed
was 460, opened up the front concave all the way,tried it in a
few spots.fan speed up 840 and i get broken kerenals out the
back,maybe I,am not putting the measuring tool in the right
spot,but I still need to move the rear move,any ideas,? I,am
going to look over the book and parts sheet when I get off of
here,thanks steve
 

[todd Hamilton]

Is it dry corn on small cobs? If so open sieves just a little, slow cylinder a little, back air off a little. I never ran a 715 but we typically adjusted the machine every field. Moisture and cob size will affect results every time.
 

[Cooney Minnie]

Usually it is necessary to adjust from field to field, or hybrid to hybrid.

If you are getting a lot of fines, you probably need to look at the rear of the concave setting- are cobs coming out whole? If they are split in two the long way, you need to be open more. If concave is where it needs to be, I'd start by lowering the cylinder speed, but making sure you are still getting all the kernels off the cob.

Adjust the sieves as mentioned above. Lowering fan spped will keep the fines in the machine, but you still have fines.

Keep in mind some corns have softer kernels than others. they require slower cylinder speeds to get the job done. It may be difficult to to get some of them to shell perfectly... especially if it is low test weight, or didn't get ripe before frost.

good luck!
 

[Kell]

Having just dealt with the same problem in WI corn with a different make of combine, here are my general corn shelling suggestions...

1. make sure feeder, cylinder bars, concaves, clean grain auger, and elevator are in good usable shape; and make sure engine speed is correct.
2. set combine as your OM suggests.
3. set combine ground speed to feed combine evenly w/o overloading. *
4. adjust cylinder speed to minimize damage. **
5. if adjusting cylinder speed doesn't eliminate damage, part of the concave must be fully opened, reset to OM recommended cylinder speed, and repeat 4.
6. adjust concave clearance to produce fully shelled cobs out the back of the machine. ***

* too little ground speed and the corn will sit in the cylinder grinding away. the cylinder can handle A LOT of cobs in easily shelled corn, you will likely overload something else behind the cylinder before you have too much corn in the cylinder.

** generally, cylinder speed is the key to reducing damage. however, if you need to maintain a slower ground speed, a faster cylinder speed may actually be needed to maintain good flow of grain through the cylinder, preventing damage.

*** reducing cylinder speed may result in more kernels left on the cob behind the machine. close the concave by about 1/8" at a time until complete shelling occurs.
 

[Kell]

meant to say...

** generally, slower speed is the key to reducing damage.
 

[markcasper]

Is the quantity of cracked corn not too much? You may be a perfectionist like myself and find out its not too bad when you look at a few of the neighbors total results. Just saying. It sounds like you have done everything I would do in getting it set for shell corn. I always set the cylinder spacing and speed so that you'll just find a stray kernel or two here or there on a cob, and that usually ends up giving the best results in terms of the least amount of cracked corn.
 

[1206SWMO]

Do you have filler bars in your cylinder??
 

[fixerupper]

Tighter concave and slower cylinder speed is usually the cure for cracked kernals. Kell has it pretty well spelled out. If the concave is too wide the cob will tumble around as the kernals are being shelled off of it. You want just enough concave clearance to roll the cob through but not break it up. Jim
 

[steve in wi]

i will start over with all specs and set the rear concave to one inch.thanks
 

[steve in wi]

OK,I set the concave to spec,checked beater,set both sieves to om,checked elevators good,and slowed fan speed.the cyl will only go down to 450 425 and that's it the belt is even with the pulley so that's as far as it will go.cobs are coming whole and clean out the back,just the very small kernals are on the cob.opened the sieves to get trash into tank.how much grain should be going threw the tailing elv?,I just thought of the feeder house was causing something,have to check when I get back out.thanks steve
 

[Kell]

Should be getting almost zero whole kernels coming through the tailings. If you are seeing trash in the tank, open the air first until you think corn is being blown out. Pretty tough to blow corn out with air, so you might be able to open air all the way. Then, if you're still seeing some trash in the bin, close the sieve slightly, but not the chaffer. If you start to see more than a few kernels per paddle in the return at that point, open the sieve back up and live with the trash. The trash won't weigh much in the sample at this point.