Olympus WHK 10X-20L-H Maintenance

[ethicalhacker]

I have an Olympus WHK 10X-20L-H eyepiece. The lens shade/hood slides straight in and out on a track but nothing turns. I assume this eyepiece contains a helical mechanism, and it's just froze up due to old grease. Does anyone have any tips on how to take it apart without breaking it?

[woyjwjl]

I have encountered the same problem. If I remember correctly, the thread does not seem to exist. I removed it with a lens wrench

https://www.microbehunter.com/microscop ... 25&t=14788

[ethicalhacker]

The WHK 10X-20L-H and WHK 10X-20L are different. Removing the lens shade/hood from a WHK 10X-20L is easy, but I'm not sure how the lens shade/hood is supposed to come off of the WHK 10X-20L-H. It does not rotate like it does on the WHK 10X-20L.

[ethicalhacker]

The textured plastic ring just pops off. Next, the metal shade with the white lettering on it needs to come off. It has some very fine pitched threads that have lock-tight on them, which are all the way up near where your eye goes. If the helical mechanism is even close to working, it will unscrew before the lock-tight lets go.

Do not use the binocular/trinocular head to hold the back of the eyepiece while unscrewing the front. Use something like a rubber grip wrench because the tiny screw that sticks out of the eyepiece that engages with the head can strip out of the eyepiece shell.

Extensive heating and chemicals are important.

You really don't want the sleeve that the shade screws on to hop off its track, but if you put too much force on it, it will. Once it's off its track, there's no way to separate the sleeve and the shade. Only differential heating would have a hope of getting it back on the track. You've really got to get that lock-tight to let go. You can't remove and clean the optical elements either without getting it off. The lens wrench holes are under it.

I suggest finding a unit with at least a half-way functioning helical mechanism. Beware cross threading on reassembly. Be gentle and patient. You can trash it so fast it will make your head spin.

[woyjwjl]

Interesting, especially the pain of others

There will be double happiness with pictures

[Tom Jones]

Heat is your friend. I think I've even used Kroil or mineral spirits a couple of times. I've cleaned and lubed (with a helicoid grease) quite a few of the -H eyepieces. They're a bit of a pain, but certainly doable. Here are some photos to show you what you are up against:

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I wouldn't even take out the guide screw for the lens shade slide. It's REALL small, easy to loose, and a pain to put back into place.

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2018-11-05 09.35.30.jpg (75.26 KiB) Viewed 1295 times

[Tom Jones]

And a few more... The helicoid screws are very touchy when it comes to rethreading them back together. If you get them cross-threaded, you can jam them together so it will be very difficult to get them apart. It will take quite a bit of finesse. As you can see, the threads that hold the eyepiece shade at the top of the sliding assembly are really small and even harder to rethread. It's doable, just be really careful.

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2018-11-05 09.53.37.jpg (129.28 KiB) Viewed 1294 times

[woyjwjl]

Great picture!

This gave me confidence to separate the lens group of B2-NC (expensive NIC condenser) from the base.

The thread seems to have been added with anaerobic adhesive before leaving the factory. Do you have any relevant experience?

[Tom Jones]

I've never tried to remove the lens assembly from my BH-2 DIC condensers. I've cleaned and lubed them, but nothing more. Never had a need. You're probably right about Olympus using thread locker though.

[ethicalhacker]

Great pictures, Tom! Thanks!