Uh........add Alfalfa Seed to the list of crops that have to be shaved. Thus the invention of rock traps? That being said I've put no less than 5 different pieces of steel though my STS in the last 3 years, 3 triple K teeth, one alloway cultivator cutaway disk assembly, and a pair of channel locks believe it or not. And yes I've had to heat, torch, weld and hammer a couple of concaves, and replace one set of 3 threshing elements and 4 sets of 3 separating tines. All but one went through when combining A. Seed the other went through when doing pintos. BTW I hate the sound it makes when something gets past the rock trap.