[Leica] 90 Summicron (Canada): still front-focussing!

[Peter Cheyne]

Before Xmas, I sent my 90mm Summicron to a repair-man in Japan to fix the
front-focusing problem. By front-focusing, I mean that when I the
rangefinder makes it look like the lens is focussed on the eye, the focus
of the lens is actually on the tip of the nose, or even a little closer to
the lens. The repair-man said a few days ago that he took the lens
completely apart and couldn't come up with a way to fix it!

It's back in my hands today, and, as the man said, it's still
front-focussing.

I tried Dante Stella's suggestion of adding Scotch tape to the focus cam,
intending to add 3 or 4 coats of nail varnish if that helped, but the tape
only increased the front focussing problem. Am I right to deduce from this
that making the focus cam protrude a little more (by, say, adding nail
varnish) will bring the focus nearer? Here is a photo showing where I am
putting the Scotch tape:

https://flic.kr/p/PHj5ho

Without the tape, the lens is front-focussing about 2 or 3 cms from about a
120 cms away. With the Scotch tape, this becomes worse, front-focussing by
4 or 5 cms.

The repair-man in Japan was recommended by a colleague who also uses
Leicas, but he is stumped at how to correct this lens. I asked Leica Japan
too, but they say they can't correct lenses that old, and don't have the
parts. I didn't know you needed new parts to calibrate a lens. I suppose
that's a stock answer for anything to do with older lenses.

So, I don't know what to do. Am I not properly understanding Dante's
suggestion? Should I send to someone in the USA, such as Dan Goldman? What
is his turn-aroud time like, and is there anyone a little faster but still
competent?

Still looking for advice!

Peter