F_K all came with 5 concave bars - fine for wheat, a power killer for corn , soft red winter wheat and soybeans. We found half rounds were the ticket for corn, we left two rounds in for wheat and soybeans but changed the door bar out for channel in these crops. Easy to do. IF we needed more threshing we added another concave in position n2. Also we found the high profile concave worked well in dry corn, white corn and even popcorn. Hardened widespaced bars were great in wheat, soybeans but we found unless the FRONTS of the leading edge were hard surfaced there would be a leading 'tit' that would damage corn that would appear after about 500 hours of operation. Grinding off this tit or lip was ok but a hard job. IF you have Trimpe or someone hardsurface your bars, make sure they do the front leading edge to avoid this leading edge spear on the cyl bars that can damage some crops. lap filler bars. These are great for corn, IF you limit cylinder speed to no more than 650 rpm they add great inertia for smooth operation in soybeans IF the bars are hard surfaced and wide spaced. Do NOT run much over this cyl Rpm with the lap filler bars in unless you are willing to accept a vist from one or more of the critters possibly entering via the cab floor
