Helical Focuser Adapters

These parts are for converting the helical from a Konica Minolta 135mm f3.5 manual lens into a telescope helical focuser. As you can imagine, every manual focus lens has helicals in them for the focusing mechanism. If your lens front element does not rotate when focusing, your lens actually has two sets of helicals - one left hand turn and the other the more conventional right hand turn. This build uses the smaller, left-hand turn because of its dimensions.

Adapting your particular lens will take some measurements and adaptation, so the models here should only inspire your own design, unless you have the identical lens (unlikely).

The flange file is designed to mate with the external part of the helical. The other part is an insert designed to sit within the helical, and flush at the top with the helical. An M3 screw passes through a hole drilled on 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.