TM 5-6675-316-14
(1) The variator or enlarging lens is mounted on the carriage stepping
assembly by a three-point mounting. This lens is also fitted with a variable
aperture, controlled by a lever. The carriage stepping assembly is located on two
rods which are fixed parallel to the optical plane. Movement, both forward and
backward, is accomplished by rotation of the helix screw.
2-23
