<font color="blue"> I would imagine that if the threads on the end of the bolt weren't destroyed, the bolt would either be bent somewhat or the hex would be chewed up so that a wrench would hold without slipping?</font>
My toothbar came with carrage(sp?) bolts, the nuts had to go on the outside. There is only about 2 or 3 threads sticking out past the nuts when it is tightened, so they are unlikely to get boggered up. As far as the bolts bending, the teeth are notched on the bottom so the cutting edge of the bucket takes all the force when when you are digging. The bolts just keep the toothbar from falling off when you dump the bucket, or backdrag.