Combines F grinding corn

On my F I run at 5_8" and not over 400 rpm on cylinder. Some corns crack easier than others as well.

I use to run some half round concave bars.It seemed to help but the corn has to be easy to shell or it wont clean the cob.How many concaves are you runningIJIf I remember right, 3 was all I ran in corn.The first 2 were half round and the last was channel for a cleanup bar.

correct - speed cracks grain

open the cylinder to 11_16"-3_4" range. and set the cylinder speed at the book recommendation. I run 500rpm and have very good grain quality samples. I also use 3 channels in the door for corn and beans and this has worked very well. Are you using factory bars.