Gary, were you still using the same tips as when we meat as you cut into our Ti (same as BB) by 3mm, on a panel side not an edge, and had only just got spinning. Also hit a wheel but only lost a small chuck. At full speed I think its possible to (hope it cant) get through the 10mm even if the bolts hold. Also the plate you hit only had 4x M6 bolts and these held due to the adjcent plates overlapping.