Below left is a closeup of the fixture that holds the grating in place when the pneumatic is fully inserted. The fixture allows for the grating to rotate in place as well as have some flexibility so that the pneumatic isn't constraining the grating position; that is acheived through the knife and ball detents shown farther below. Below right is a closeup of the rail and mounts for the magazine.
Below are a closeup of the rotation stage with a grating holder in place and a view from above of the grating insertion pneumatic and magazine sliding motor.
Left: Grating holder.
Right: Detail of positioner with groove for the knife detent (shown in a picture below).
The rotating frame that will hold the gratings, mounted on the rotator stage:
Details of the grating positioning system, including ball detent at the bottom and knife detent placement on the side.