I have a 1640 with a standard rotor, large wire concaves and bar grates. I run 30% corn, 50% beans and 20% wheat. I bought a set of cover plates from Marv for wheat and when I was taking out the concaves I discovered that there wasn't any straight bars on the rotor. The spiral ones that end with straight are on but the ones between the spiral ones are gone. There is 6 brackets. Is there a reason why these are off? I bought the machine used with 1850hrs on it. Also how much wear is acceptable on the concaves and grates? There is about a 1/16 radius on the concaves and about 3/32 on the grates. The separator bars look shot, the heads on the bolts that hold them on are about wore off. Is there any aftermarket products for the bars? I was thinking of rebuilding the concaves and grates with weld but didn't know if it was worth the time. Thanks for any suggestions.