Helical Focuser Adapters

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These parts are designed for converting the helical from a Konica Minolta 135mm f3.5 manual lens into a telescope helical focuser. Every manual focus lens features helicals for its focusing mechanism. If your lens front element does not rotate when focusing, it is likely that your lens has two sets of helicals - one with left-hand turn and the other with the more conventional right-hand turn. This build utilizes the smaller, left-hand turn due to its dimensions. Adapting a particular lens will require some measurements and adaptation, so these models should only serve as inspiration for your own design unless you have an identical lens (which is unlikely). The flange file is designed to mate with the external part of the helical. The other part is an insert that sits within the helical, flush at the top with the helical itself. An M3 screw passes through a hole drilled in the helical and also through the insert. An M3 hex nut is placed into a slot in the insert, and the screw threads through the nut. This screw serves to push a compression ring (a large 6mm wide zip tie is being used) that sits in the groove of the insert. A 1.25" eyepiece will fit into the insert as shown in the images.