How to disassembly adjustable eye tube of Bausch & Lomb Dynoptic inclined binocular body "T"?

[hans]

Was seized with dried grease. Soaking in penetrating oil overnight freed it up. Probably usable as is but but the movement is a bit slick and gritty feeling so I would like to get it all the way apart and clean/regrease if possible. Sticking out to the right in the photo is the inner tube that threads into the body, on the left is where the eyepiece goes. The small threaded hole by the knurling is where a retaining screw for the diopter scale goes. Looking into that hole with a stereo microscope I think I can see it cutting through another thread as if the piece to the right of the thin seam is a threaded retaining ring with the diopter scale screw hole drilled/tapped through it to act as a lock? I can't get the retaining ring (if that's what it is) out by hand. Wondering if someone has taken one of these apart and can confirm that actually is a threaded retaining ring before I try more forceful methods...

[hans]

Freezing the whole thing then dunking the outer tube in hot water released the grip on the retaining ring enough to get it out by hand. Photo for future reference:

[BramHuntingNematodes]

That's a fine job there hans. How's the rest of the scope coming along?

[hans]

Looking good so far. Except for this eye tube everything else was moveable and seems to work, just very stiff with old grease. I haven't messed with it much not wanting to break anything before relubricating. Binocular body is the first thing I took apart, almost ready to go back together now. Some haze in the eyepieces and a few small spots of fungus on the prisms but they cleaned off easily and the glass is in good condition. There is an asset tag "Oklahoma Medical Research Foundation" but it doesn't appear to have actually been used much, mainly dings, scratches, and hardened grease from storage.

[BramHuntingNematodes]

Ah yeah that's swank. I just got one of those phase condensers put it on the Dynazoom works great those old 60s phase achromats are so good. See if you can get some 15x Hyperplane eyepieces they got good views and the best relief you'll probably get of that era. You can get some of the later big B&L can eyepieces, you know the old 10x WF classics, and they look like they got a wider field . Only trouble is you can tell that the extra area they are revealing was not of much concern to the objective designers as the quality drops off quick. Those later cans got good relief though.

[hans]

Yeah I got it to try out phase contrast. The whole microscope was around what just a turret condenser with annuli for the AO/Reichert infinity systems goes for. Completely logical. Not just an excuse to buy another microscope...

It came with 10X Huygens eyepieces so yeah, will probably want to upgrade.

[hans]

Ok Bram what's next on this one... took out all the screws I can find, hub in the center spins stiffly with a pin spanner but doesn't seem to thread in or out, turret+hub is clunking around free from the support casting the bit sticking down from the hub in the center prevents it from being removed completely. Should the hub press out of the turret and is just being held in by hard grease?

[BramHuntingNematodes]

Oh yeah I just took that one apart. I will try to post pictures later tonight.

[BramHuntingNematodes]

OK so here's the deal in order to get complete access to the annuli only 2 screws need to removed, both from the top center like so:




If you have the two adjustment wrenches it may be useful to screw them both all the way in. This will move the axis of rotation far enough away of the lens assembly to remove the screw easily from under it. It may appear as though the screw is not coming out, but this is an illusion. It is taking the entire platter along with it! Make sure to push it down as you go.

[BramHuntingNematodes]

Also, thanks Hans-- after taking the whole thing apart I noticed the top half-ball lens of my condenser was way askew. I straightened it out readily. Over the last few weeks I have been trying to adjust the head and field aperture trying to get the light to line up better!

[hans]

Perfect, thanks. The big flat screw I was calling the hub was seized pretty well to the roughly-triangular piece with the detent spring but seeing what's inside gave me some confidence to torque on it until it broke free.

[BramHuntingNematodes]

No problem tell me when you figure out what sized socket you use to put that iris together again I think I got one around here that looks like that...

[Plasmid]

The dreaded iris leaf , it took me 2 hrs to reassemble a 16 leaf field diaphragm I mistakenly took apart.... Never doing that again, how often should one take apart and regrease the wheel on the condenser?

[hans]

Yeah I was hoping to avoid taking the iris apart. There was no dried lubricant on it but it was pretty gritty feeling and didn't move very easily. Tried exercising it while gently swabbing the leaves with alcohol but it was just getting worse. The swabs were coming off brown so maybe the grittiness was some very fine surface rust?

[Plasmid]

Mine was sticking and would actually bend the Iris upwards , in the shape of a cone when completely closed, I dont know if it was a greasy residue on it that was causing it or if one was bent. It took straightening a couple of them and cleaning them with alcohol to get it working again, to this date I haven't found the answer to whether they need to be greased or not. Have you determine what the residue on the annulus is ?

[hans]

...to this date I haven't found the answer to whether they need to be greased or not.

Yeah there seem to be conflicting opinions. Maybe originally the official service instruction would generally have been not to lubricate them, but now decades later with the factory surface finish worn off or deteriorating some lubrication is helpful?

Have you determine what the residue on the annulus is ?

Mostly just dirt and grime which came off easily. The fuzzy white spots on top I think are fungus which I had not run into before. Luckily all the spots I have found so far (a few on the prisms in the head too) have cleaned off easily with deionized water and IPA with no damage to the glass underneath. Interestingly, there is some oxidation of the metallization in one annulus that looks suspiciously like a fingerprint. It is definitely internal, not on either surface. B&L factory worker accidentally touched something they shouldn't have, I guess?

[Hobbyst46]

Leaf aperture should be dry. Neither greased nor oiled. The best cleaning fluid in my experience is heptane or octane or white gasoline or petrol ether (for this purpose they are all the same).
Cleaning with Q-tips can leave small fibers or string residues in between the leaves. These can be pulled out with Jeweller's tweezers.
I do such jobs under a 10X magnification stereo microscope, using top illumination.
Once the aperture is cleaned and dried it can function a very very long time without maintenance.

[hans]

Any idea what the original finish on the leaves generally is? Something like black oxide?

[hans]

Almost all the way apart now, not sure about the fine focus knobs though. Removed/loosened all screws I could find but the knobs still will not rotate relative to the shaft or pull off with moderate hand force. Is there anything else holding them on?

[hans]

The knob on the left side of the microscope came off fairly easily after freezing and hot water but the right one was more stubborn. After seeing that the left one was only held on by dried grease I used a heat gun on the right one then pin punch to drive the shaft out of it. I'm guessing the next thing that needs to come out is the large, hollow black cylinder that pins the upright to the base and has the fine focus shaft in the center, but it seems to be similarly glued in place by dried grease. Probably just going to apply penetrating oil periodically for a few days before trying anything else. The fine focus shaft is still captive in the black cylinder due to the lead nut or whatever is in there, which hits hard stops in both directions when turning the fine focus shaft.

[hans]

Got impatient and drove the black tilt axle out using a socket as a punch. Two little screws radially into the shaft are travel stops for the lead nut and taking them out allows the shaft to be unscrewed all the way out. Then the little ball and spring in the hole in the side of the lead nut (anti-backlash?) shoot out when you pull it out of the slot in the black cylinder. (Luckily the ball hit my tee shirt and fell back on the desk rather then ricocheting around the room.) Both ends of the shaft are tapered where they fit into the knobs and there are no set screws in the knobs, just the screws in the ends that press them onto the tapers.

[BramHuntingNematodes]

You some pretty good teardown pictures here for future reference. I don't think I ever took my fine focus apart that far. I do recall the action being the slightest bit tricky to reset properly. Persistence paid off

[hans]

Yeah biggest problem taking apart this old, seized stuff is knowing whether parts are held together by grease only or by some delicate mechanism you are about to destroy. Have you ever seen a parts diagram for these? I found one for Dynazoom and the inner fine focus part looks very similar but the outer axle, rather than being the tilt joint, drives coarse focus in a way I don't really understand just from looking at the parts diagram?

[hans]

Seems to have survived all the disassembly trauma. Light source is currently the front optics/bulb section of an AO 1031 for the 10 series. (The electronics were crusty and not working so I just use a bench supply.) The illuminator is not a good match for the B&L 1.25 abbe condenser on the phase turret because focusing on the field iris puts the condenser way too low, but works well other than the lack of precise illuminated field control. Going to try an 1130 (infinity-corrected) from an AO 110 next. Anyone know what illuminator with field iris would have been used originally with the phase setup? External illuminator and mirror? I saw "Opti-lume" but that does not have a field iris, if I understand correctly?

The cheek cell photos are with the 4 mm (43X) objective using a Panasonic GX850 handheld with 12-32 mm kit lens at 32 mm through the 10X Huygens eyepieces.

[BramHuntingNematodes]

Probably a mirror and one of the good illuminators. My example from UGA had a mirror, for instance.

[hans]

Probably a mirror and one of the good illuminators. My example from UGA had a mirror, for instance.

Did some more looking through the various catalogs and manuals I downloaded and saw this. Do you know whether the mirror used in this sort of setup is flat or concave?

[BramHuntingNematodes]

B&L mirrors are flat in one side and concave on the other. The concave side is only for low magnifications, 10x or less usually. You would be fine using only the flat mirror for a phase contrast microscope.