Oleo's right, I once had such a bad shimmy that I thought the engine would fall off.
Try using this philosophy, "its not the mountain you just missed you have to get worried about, learn from it , look ahead to avoid it happening again." In some knackered old crates you cant avoid shimmy once the elevator has run out of puff, you just got to live with it and A defect it before it hurts sombody.
S