carl zeiss jena coarse focus mechanism?

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PeterArmitage
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Joined: Fri Oct 12, 2018 1:11 pm

carl zeiss jena coarse focus mechanism?

#1 Post by PeterArmitage » Fri Dec 28, 2018 10:42 am

Do any of you have experience dismantling, cleaning and greasing the coarse focus mechanism in a Carl Zeiss Jena Ergaval or Amplival microscope? I can't figure out how to completely dismantle the mechanism, and would appreciate advice re. how to proceed further than what you see in the appended photos. I took the base off and greased the gears as best I could, but I fear that I over greased them. As a result, I'm getting some slippage on the focus. I used a heavy grease for the lubrication, namely, Nyogel 795A. Thank you.
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MicroBob
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Location: Northern Germany

Re: carl zeiss jena coarse focus mechanism?

#2 Post by MicroBob » Fri Dec 28, 2018 2:19 pm

Hi Peter,
I can't help you here but with Zeiss Jena there is one general tip: They used grease that had an unusual tendency to harden. This can be a problem when dismantling because things just don't move when you loosen a screw. It helps a lot to soak the microscope micus optical components in warm temperature (60°C). This can be done with an IR lamp for example.

Bob

Hobbyst46
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Re: carl zeiss jena coarse focus mechanism?

#3 Post by Hobbyst46 » Fri Dec 28, 2018 2:31 pm

Not a Zeiss Jena but on my Olympus VMZ rack the Nyogel 767A does a good job. In the Nye literature, the 767A, rather than tyhe 795A, is recommended for microscope focusing rails. I bought a 50g tube from Amazon.

PeterArmitage
Posts: 37
Joined: Fri Oct 12, 2018 1:11 pm

Re: carl zeiss jena coarse focus mechanism?

#4 Post by PeterArmitage » Fri Dec 28, 2018 11:40 pm

Thanks MicroBob and Hobbyst46 for your replies. Yeh, I heard that the Zeiss Jena microscopes had "Russian tank grease" that hardened like glue. I have been using heat to help loosen up the badly stuck parts. The coarse focus is fairly well loosened up now, but not completely. But the new problem is probably that the replacement grease, Nyogel 795A, is too light. I'll try the heavier grease.... All the same, I need to get the focus mechanism fully apart in order to properly lubricate moving parts. I'll try the Mikro-Forum next to see if anyone there has experience with this....

MicroBob
Posts: 3154
Joined: Sun Dec 25, 2016 9:11 am
Location: Northern Germany

Re: carl zeiss jena coarse focus mechanism?

#5 Post by MicroBob » Sat Dec 29, 2018 7:34 am

PeterArmitage wrote: Nyogel 795A, is too light.
Some microscope stands have an adjustable coarse focus mechanism - you might be able to adjust it.
Coarse forus is not that important as you don't use it that much. As long as it is not too hard to move so the gears would suffer it might not be necessary to dismantle it completely. The fine focus has to moove very nicely because otherwise the tiny gears would break very soon.

Bob

MWK
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Joined: Sat Jan 11, 2020 8:31 pm

Re: carl zeiss jena coarse focus mechanism?

#6 Post by MWK » Thu Jan 16, 2020 3:22 pm

I dismantled one recently, let me know if you still need help with that.

PeterArmitage
Posts: 37
Joined: Fri Oct 12, 2018 1:11 pm

Re: carl zeiss jena coarse focus mechanism?

#7 Post by PeterArmitage » Wed Dec 09, 2020 2:42 pm

Good day MWK. Thanks for your January 2020 post regarding my Carl Zeiss Jenna focusing mechanism. I acquired a second arm stand for this microscope because I could not solve the slippage problem I was having with respect to focus. Improperly greased by me perhaps? This is now installed but I can't focus it. It seems to me that the screws on the drum shown in my photo (above) are responsible for setting the upper and lower limits of the coarse focus. Is this true? These are the two screws on a drum that is attached to the focus knobs outside the arm. They point towards the bottom of the microscope.

Is my understanding of the functions of these screws correct? If not, what purpose do these screws serve? And if not, how do you set the lower limit for the focus mechanism?

Thanks in advance for your help with this! Best wishes, Peter

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