I am trying to disassemble an altimeter. My understanding is that that it is a British altimeter from the WWII era and the markings on the face are XIV8 (P) 6A1213. I have removed the front face glass, and the knob for adjusting the altimeter setting but I cannot slide the works out of the case. The obvious thing to do is look for some screws in the back of the instrument that would secure the works but there are none. There is only a fitting for the static line that is firmly screwed into the case. There is nothing on the outside of case that appears to hold the works in. Anyone have an idea on what the correct procedure is to remove the works?