Any Advice - with a Nikon 40x/0.85, whose coverslip ring is stuck at 0.23?
The vendor is conciliatory, and will take it back, but I thought I'd ask...
Recipient's description:
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It’s set a bit wider than 0.23, and won’t budge. Maybe there is a way to lock/unlock these things?
Under a dissecting scope , there is one small screw that might conceivably have acted like a set screw, but no, loosening it made no difference.
Visible under the dissecting scope is the fact that three very small screws on the barrel appear to have been torqued very hard, to the point that the (standard tip) heads show some deformation. The deformation suggests to me that someone had a hard time getting them out—or perhaps just in attempting to do so. They are too small for even my smallest jeweler’s screwdriver to fit.
Also, this objective has the kind of protective tip that recesses into the objective if pushed. If pushed, it comes back out, but at a measured pace that requires about three seconds. Can this be by design, or does it suggest that things are too tight or otherwise gunked up?
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If the vendor is happy that we "have a go", any suggestions?
Some solvent applied as one drop to the ring?
Heat? How much? Hair dryer?
Correction/compensation ring seized
Moderators: rjlittlefield, ChrisR, Chris S., Pau
I would only have a go at it if the seller will take it back if it gets much worse.
The pace at which it pops back out can be from the wrong constellation of manufacturing tolerances but is more likely to be : oxidized lubricant which probably should not even be there, aspirated detritus (ditto ) or worse stigmata of previous ham fisted cobblings and botchings.
But if the glass looks good and you have nothing to loose find or grind a screw driver. You could try some lighter fluid on the retraction snoot. Squirt it on a lint free cloth and give it a couple wipes and operate it to try and bring excess lubricant or dirt out and reclean it. See if that helps.
For the past few years I have been lubing such things with white teflon based grease which I happened to get from Zeiss but is available from electron microscopy suppliers. It is good at high temp and high vac so it will not outgas petroleum films onto your optics and will never harden up.
It's not as good a lube as oil but irises , focusers and zooms don't move very fast. It's viscosity usually gives a reasonable feel.
I have never been able to bring myself to point a heat gun at any optic.
I would be afraid of damaging some lens cement though it would as likely anneal it and might be good for it. You would want the temp change really slow and you would not know where you needed to stop. I have read lots of microscope service manuals and never seen a heat gun mentioned. (I do have and use several of them up 1900 watts)
Good luck!
The pace at which it pops back out can be from the wrong constellation of manufacturing tolerances but is more likely to be : oxidized lubricant which probably should not even be there, aspirated detritus (ditto ) or worse stigmata of previous ham fisted cobblings and botchings.
But if the glass looks good and you have nothing to loose find or grind a screw driver. You could try some lighter fluid on the retraction snoot. Squirt it on a lint free cloth and give it a couple wipes and operate it to try and bring excess lubricant or dirt out and reclean it. See if that helps.
For the past few years I have been lubing such things with white teflon based grease which I happened to get from Zeiss but is available from electron microscopy suppliers. It is good at high temp and high vac so it will not outgas petroleum films onto your optics and will never harden up.
It's not as good a lube as oil but irises , focusers and zooms don't move very fast. It's viscosity usually gives a reasonable feel.
I have never been able to bring myself to point a heat gun at any optic.
I would be afraid of damaging some lens cement though it would as likely anneal it and might be good for it. You would want the temp change really slow and you would not know where you needed to stop. I have read lots of microscope service manuals and never seen a heat gun mentioned. (I do have and use several of them up 1900 watts)
Good luck!