microscope eyepiece dismantling

[gerry maddenParticipant @gerrymadden53711]

I never used to be defeated by things until this forum came along but asking a question does save one a great deal of time allowing one to get on with other 'important" things in the workshop

My latest challenge is dismantling my eyepices. In many places OMT have done a great job of hiding the typical 120 deg. grubscrew connections, with a fine push-fit brass sleeves, which were then painting over to make it look solid. I think I have found all of these and I'm down to the coarse focussing threads. These badly need fresh kilopoise grease so I have to get them apart and this is where I'm stumped. I'm hoping that someone will know the secret behind this particular assembly or can suggest something to try that I haven't considered.

The eyepiece assemblies look like this:

The outside 'focussing sleeve' with the straight knurling will currently rattle axially by a few mm's if the focus is opened to its limit. If the focus is closed down the 'focussing sleeve' becomes tight. From playing with the assembly I 'think' the internal construction must be something like this:-

If this theory is correct, to get it all apart, part no.2 the focusing sleeve, has to be separable. But I just cannot see how to do this. My expectation was that the pieces of the sleeve to either the left or the right of the knurling would unscrew from the knurled section. However I see no way to grip them other than by friction. I tried that, and it wasn't successful. In any case I carefully brushed all the paint away from the likely joints and viewed them under a microscope. I could not see any obvious junction.

What I have detected though is that the 'zero mark' on the tapered portion (on the right of the knurling, visible in the first picture) is more than just an engraved mark. It appears to be a joint and if one forces a screwdriver under the sleeve and levers it you can see the joint open very very slightly. But that's all I can make it do, it will not allow itself to be prised out of where it currently sits.

Clearly I'm missing something so any thoughts or experience here would be appreciated.

Gerry

[gerry maddenParticipant @gerrymadden53711]

[Clive HartlandParticipant @clivehartland94829]

I have seen this before, the angled ring with the cut in it is usually a left hand thread and turned opposite to the collar.

They are often quite hard to turn but pressing in on the cut will start the unscrewing. be aware that the Kilopoise comes in a few different viscosities.

[gerry maddenParticipant @gerrymadden53711]

Thanks very much Clive. I will look at that.

Re the grease, I purchased a small pot from China recently. There were no numbers in the advertisements indicating its actual viscosity, only references saying "good for camera lenses". I've tried it on a number of things all with good results so far – except on a 10" rotary table. You can imagine what that was like ! Walking in 2ft of syrup would be a good description so off it came and on went a standard grease and all's well again.

Gerry

[gerry maddenParticipant @gerrymadden53711]

Well done Clive Sir ! I just picked it up and turned it the 'wrong' way with my bare hands and look what happened !

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