this is cam for 127mm lens,
But how long the radius range a cam causes?
I used a usb micro scope to take photo of cam, and enlarged it, then make some distance measures.
After carefully measuring, converting digits into a curve, we found that outer curve of 127mm cam actually causes mirror rotate within 1mm range.
That means a lot, range finder that 110B equipped, focus from infinity to near 3.5feet, all controlled within 1mm range.