I recently acquired a tiny KOSMOS rotary microtome made by E. Zimmermann. KOSMOS is a german company that traded scientific stuff for decades. These little rotary microtomes were made in several different versions for at leas 65 years. Weight is about 5kg and it lives in a nicely made wooden box. It probably is the only rotary microtome that comes with a desk clamp!
Originally it had a housing that went missing and a round mounting plate to melt paraffin blocks onto. The grey block holder on the photo is most likely a later addition. I removed it and replaced it with a clamp for modern tissue cassette blocks. It is a nice little microtome that can be carried to group meetings without dislocating one's back. The arm in front is part of an section The microtome was last used 35 years ago by a medical student and urgently needed a service. I dismantled it, cleaned an lubricated it,adjusted the guides and assembled it. I also glued the µ scale onto the base as it was ratling around without a mount. The knives had what looked like a little surface rust, but these very high carbon steels tend to develop rust that enters the material like a worm hole. I had to grind away quite a bit of steel to get an edge without nicks. Now it cuts nicely. As a sample I cut some sections of a paraffin embedded blackberry twig, sectioned to 10µ, stained with Wacker W3A Sim, perhaps too old, mounte in Euparal. The image will improve further when the Euparal dries on the 45°C hot plate.Bob
For most parts I have used HLP 68 hydrailic oil, for the vertical movement GLP 220, a sticky machine way oil. There are three doveteiled ways, one for the setting of the section thickness, one for the repeated up/down movement, one for the progress of the block towards the blade. The latter two are adjustable. Not original is the way the scale is mounted and the cassette holder, 3D-printed with a base soldered from two steel parts.