Centering Lomo Min-4 Polarizing Stage

[ldflan]

Hello, all you Soviet microscope cognoscenti -

The postman recently delivered a beautiful 1950 vintage Lomo Min-4 polarizing petrographic microscope to my office. Such a kind man. Anyway, I have everything working well, but am having a very hard time centering the rotating stage, and am hoping someone has some tips for doing so on the Lomo Min scopes. The stage appears to be the same as used, for example, in the later Min series. It has no obvious centering screws around the perimeter. Underneath, there is a threaded collar ring with two holes for a spanner wrench. My guess is that this collar retains the bearing assembly, so I have not been inclined to try to open it. In this same collar there are also three very small set screws, which I presume lock the collar so that it does not shake loose or get in-advisedly disassembled by someone like me.

The only obvious option is to loosen the four screws that mount the stage to the riser, try to center the stage, then tighten the screws and hope it holds in place. This is not an efficient or even effective way to do things!! I must be missing something. The scope is very well and effectively designed in all other particulars.

Does anyone have any hints?

Thank you!!

Leonard

[MicroBob]

Hi Leonard,

you might find the answer here: http://www.mikroskopfreunde-nordhessen.de/lomo.php
Or ask Wolfgang, the site owner who knows a lot about LOMO.

One method of centering is the use of double excentric rings that are twisted against each other for centering. This is for instance used in classic Zeiss binoculars.

Bob

[ldflan]

Thanks. Great resource, but I don't find it there. I have emailed Wolfgang. Hopefully he knows. The eccentric rings idea struck me as a possibility, too, but I cannot quite see how it would work with the mechanism as I understand it.

Leonard

[Dmi3n]

Good afternoon. As far as I know, LOMO MIN polarising microscopes don't have centerable stages. The objective and the condensor are centered instead according to lab technician who worked with MIN-8 (newer model with same stage). If you want I can try to find Russian manual for MIN-4 and translate parts redarging centering if there are any.