Partially off topic: I had a dynamic balance done on my timber MT prop once.... The LAME forgot to fully screw in a spinner screw which departed on the 10 minute flight home. Unbelievably the screw took out a huge section of the prop trailing edge, around 20 cm (along the prop) x 4 cm (into the prop from the trailing edge). To say I was mildly peeved was a bit of an understatement.