Wild Leitz Laborlux S Coarse/Fine Focus

[SLOBEERGUY]

Hello -
We have a Wild Leitz Laborlux S microscope in great condition for its age. Recently (and probably foolishly) we pulled apart the coarse/fine focus adjustment mechanism as it was becoming very noisy due to old dried up lubricant inside. Now - for the life of me - I cannot get it to function properly when re-assembled. I think the root of the problem is that I am not understanding how the focus tension mechanism is supposed to work.

When I put the assembly back together I get one of 2 scenarios. A) It seems to function normally but the range of motion for the stage is limited or B) I get better range of motion on the stage but the tension is too low and the stage falls down slowly

I'm hoping someone familiar with the coarse/fine focus and focus tension adjustment could help explain to me the process in which it functions so that I might be able to reassemble our microscope and get it back into use.

[PrecisionInstruments]

What exactly was disassembled? The focus barrel mechanism or the z-axis linear bearings?
The barrel has no influence on the height stop, though it is crucial for tension.
Which knob is drifting/falling? Coarse or fine knob?

[SLOBEERGUY]

Just to follow up - I finally figured out the issue with the focus on this microscope. When I removed the focus assembly completely I realized that the bronze end of the assembly was supposed to spin freely with the coarse focus knob. It was caked with old dry grease and wouldnt budge. I removed the bronze piece and cleaned and regreased it and the bearing inside. Everything works correctly now.

I didnt take many pictures while working but this picture shows the piece that should rotate with the focus knobs and not stay stationary.

[PrecisionInstruments]

Great!! Yes, the lubricant in these barrels turn green after a period of time (good old Leica 410). The two brass lock nuts are to be set to a nice tension where the coarse focus feels a nice drag, but can cause the stage to fall if too loose.