There is a simple way to avoid the hassle of the D3 focussing tracks.
I bought two used Omegas, a D3 and a D4, one without lenses and one with the ‘wrong’ lens, and ended up with 6 tracks I cold’n use.
So, when closely looking how the autofocusing system worked, I saw that, actually, the lens-plate is pivoting up and down due to the ‘pushing/pulling’ of a wheel on a track that is correctable by turning a knob with a concentric wheel on it. The simplest and surely the smartest way to do!
Then I figured out that, perhaps, this pushing/pulling—pivoting thing could be replaced by a screw driven—pivoting system. After some trial and error, I came out on a simple and cheap system. I first dismantled the whole tracking system as it was useless. Than I made a new ‘thing‘ made of two brass blocks with some threaded holes in it, a handful of nuts and bolts, a threaded rod, a knob (recycled from an old lawn-machine), a spring and lots of imagination.
To make things simple, look at the attached picture…
Note that the brass blocks can be substituted by something else, use your imagination.
One might need to ‘modify’ the lens-mont plate/tube too, and have it adapted to the focal length of the lens, see the picture.
This works as simple, perfect and issueless as possible for years now.
Philippe