Yes Argo I agree wholeheartedly with your assessment. Especially the fact that the nut is one of the causes of the bending. I agree with the idea of making a handle that will limit the torque that can be applied. I think when Harrison designed the lock they assumed that users would be imbued with a modicum of engineering "feel" and would tighten it sympathetically. Clearly that has not been the case throughout the life of the machine. I'm going to be looking to see if there is scope for the dimensions to be subtly increased to make the part stronger, too. Thanks for a very useful and thought provoking post.