Disassembling Objective lenses

[ktvaughan]

Is there a good source for how to disassemble and clean objective lenses?
I have oil immersion lenses where the oil gets into the barrel and jams up the nosepiece.
I'd like to be able to open it up ans clean the oil out.
BTW, is there a good way to keep the oil out.
This is on an inverted Zeiss 200M.

[Greg Howald]

1. I am not familiar with your particular objectives. But.
2. Some objectives are designed so the front lens can be removed from the front of the objective by unscrewing it. This facilitates cleaning the forward lens without disassembly of the entire objective. Most do not give you that advantage.
2. Most objectives can be disassembled by removing the usually black colored gasket on the back of the objective. Once removed you should see a ring shaped screw with slots at 180 degrees. That screw turned in the counter clockwise direction will usually get you started with disassembly.
3. Be extremely careful. Easy to get apart but if you don't get it back together right it will be more than problematic.
4. If you are able to clean it and get it back together properly, which for me would be a miracle, never get it near oil or any other liquid again.
5. Oliver Kim has a you tube video on his microscopy Site where he disassembles an objective. Watch it about three times before you make the attempt.
6. Good luck. Greg

[Hobbyst46]

Since the OP wishes to repair oil immersion objectives, it is essential that they can be used with oil immersion after the treatment...

Oil immersion objectives on inverted microscopes are under even a higher risk of being flooded with oil, due to dripping from top lens... especially during long sessions.
Yet inverted microscopes are the bread and butter of biological research today. So, I would imagine that any local Zeiss customer service should be able to advise about the repair in question. Especially since the 200M is not an old model.

[Wes]

BTW, is there a good way to keep the oil out.

Put an absorbent collar on the objective so any oil that is dripping away from the front lens will get trapped by the collar.

[deBult]

There is a higher viscosity (thick) type oil for inverted scopes.

[Greg Howald]

Loosening the lock ring on the objective can be a challenge when disassembling an objective. I have used a small flat blade screwdriver and tapped on it somewhat briskly to loosen the ring initially, then it turns rather easily to unscrew completely. In Oliver Kim's video he uses a caliper with pointed edges to grip both sides of the lock ring simultaneously. How ever you do it, allowing sloppiness can easily cause damage so be very careful not to scratch the exposed area of the lens.
Greg

[Greg Howald]

Regarding immersion oil, type B might work well enough for you. There may be a special type available. Do not use molasses. greg

[patta]

Link to repairs walkthrough of old objectives; pdf in Italian but enough photos to understand:
https://www.funsci.it/schede-tecniche.html
Also search thoroughly here in the forum, there are several old repair threads with loads of tips and tricks.

Sounds like you will need to re-seal the front lens. No idea! Maybe a thin rim of silicon applied from the front (try not to remove and reglue the ridiculously small front lens, may become a nightmare). Or post 4 and Post 7 to slow down and maybe stop the infiltration. The objective gets dipped in a gallon of oil?