I always was under the impression that the reason for using nylon bolts was so that they would shear if put under stress reather rip the wing or fuse apart. They really are not doing thier job if you hit hard and the bolts are left in the blocks and the bottom of the plane is ripped apart. If you just want strong bolts, use a metal one. That way you can save on the bolt cost and probably repair your plane more often.