An combine harvester comprises threshing and separating chambers having cover plates on which groups of vanes may be adjusted by individual tie plates utilizing an off-center pivot point for the vanes and a two-bolt system. The two-bolts being the maximum number of bolts needed to secure each vane wherein one of the bolts is an off-center pivot point while the other of the bolts extends through the cover plate to secure the tie plate for each group of vanes.