I've been called a lot of things in my time (mostly good!) and to add to the list is 'my knight in shining armour'.  One of my customers had knelt on her glasses when measuring for a carpet and bent the arm over 90 degrees further than it should be (imagine the arm pointing straight up in the air) as well as badly twisting the frame.  

Without them she can't work and was worried that the specs were beyond hope.  Five minutes of heat and gentle bending they are back to normal and she can go to work as normal - hence the 'knight' reference.