Build the bottom half of the Beam Splitter Top Masses, 1, 2, and 3 for creak bake. 

Assembly Notes: 
(1). Install stability legs after pulling down blades, as the base plate cannot be clamped to optics table with the stability legs in place. 
(2). Use 6kg for blade pull down mass. A 7kg mass pulled the blade past flat, putting reverse bend into the blade. There is no base line spec for the blade tip height adjuster. Therefore lowering the blade tip height may allow for a 7kg pull down mass, if necessary. 
(3). Mount the pull down wire clamp as far out on the blade tip as possible to clear stop bridge when removing wire clamp.  
(4). Used a 2mm side gap between the blade and stop bridge.
(5). Take care when moving the blade side to side, as the blade twists easily.