my Carl Zeiss Standard GFL

[imkap]

After a week of cleaning and greasing, with the advice from generous forum members it is finally ready for the all timer rally

I've read the manual for this scope but the info is pretty scarce inside. It's more like a leaflet. So I'm wondering how to use this condenser and what kind of condenser it is, I suppose it's brightfield. Not sure what is the top (flip thing lens) used for. I have realized that all the lens should be properly aligned in the centre, so I've (almost) did that. Please help if you have some info...

[BramHuntingNematodes]

It's a non-immersion fliptop. Unflip for low magnifications, flip up for higher, probably 20x and higher. They're good, and easy to center assuming the iris is still factory calibrated. Close down the iris and focus on it. You can then center the light the same way by focusing on the next iris, although hopefully that will be unnecessary. GFL is a good old scope.

[imkap]

Ok, I understand. The iris on the condenser is not factory calibrated as I have recently disassembled it to clean everything . So I assume I could center the fliptop glass on the bottom iris and then center the condenser iris with screws?

Maybe if you have some link or advice on calibrating condenser and lights it would be great. I found this: https://www.zeiss.com/microscopy/us/sol ... ation.html

[Hobbyst46]

Ok, I understand. The iris on the condenser is not factory calibrated as I have recently disassembled it to clean everything . So I assume I could center the fliptop glass on the bottom iris and then center the condenser iris with screws?

Maybe if you have some link or advice on calibrating condenser and lights it would be great. I found this: https://www.zeiss.com/microscopy/us/sol ... ation.html

This link is to Kohler illumination, which is a general procedure that is applicable to nearly all microscopes. The aim is to achieve optimized illumination of the field of view - uniform brightness, maximum contrast. On the original GFL, it is done by correct location of the light (incandescent) bulb, and adjustment of the field aperture and condenser height, while the specimen on the stage is in focus as well. The protocol is given in the GFL manual (there is a manual for the W and GFL - "G 40-114 - Standard GFL and Wl Microscopes - Operating Instructions"). (and many other microscope manuals). It is not "calibration".
In microscopes where the light bulb is fixed, Kohler involves only the field aperture and condenser.
The condenser is centered by means of two radially protruding thumbscrews in the rear of the condenser holder.
There are tiny machine screws along the periphery of the condenser, but even for cleaning the aperture blades, there is no need to touch them AFAIK.

Regarding your last response in your other thread:

Congratulations on the stage repair. Really these old Zeiss microscopes can be labor- intensive.

I bought and use dampening grease Nyogel 767A from Amazon. It is very viscous - but is the only one that I could find and buy. I am not sure that the stage needs dampening, though.
As for the focus - the old saying: "if it ain't broke, do not fix it" is especially relevant here...

[imkap]

Now I understand, I didn't realize Zeiss had an archive with everything, you actually mentioned that in a post earlier, but I just searched the internet and found a manual.
I found the web page, I don't understand German but have somehow managed to click to the right place. I will now send this pdf to them and then they give me some invoice?

[imkap]

Regarding your last response in your other thread:

Congratulations on the stage repair. Really these old Zeiss microscopes can be labor- intensive.

I bought and use dampening grease Nyogel 767A from Amazon. It is very viscous - but is the only one that I could find and buy. I am not sure that the stage needs dampening, though.
As for the focus - the old saying: "if it ain't broke, do not fix it" is especially relevant here...

It just feels a bit too loose now, although usable and we'll probably get used to it. If I get a chance I'll put some more viscous grease on the gear, but probably won't buy nyogel yet...
As for the focus, I won't touch it while it's working. I should probably switch from mechanics to microscopy now...

[BramHuntingNematodes]

The calibration is the centering of the iris relative to the condenser lenses who said.anything about Kohler? The light is probably fine but the condenser needs to be centered as those two screws have undoubtedly been adjusted many times. Of you physically removed the iris from the condenser for some reason, it may still be reasonably centered but maybe not and if not.will not be a.useful reference for.centering the condenser.

[imkap]

After disassembling my Zeiss GFL and to my big surprise successfully assembling it, I made a mistake on the most unlikely place. I have used too much force on the screw holding the filter and it broke... I was quite angry with myself about that...

So for future reference here is how I repaired it, it looks and works like the original



First I have carefully sanded down the remaining part of the broken screw with a bench grinder. Not completely as I didn't want to damage the smooth part.
After that put the screw into the bench drill and the 2.5mm drill bit into a vise and manually centering it on the screw. (You can go smaller but not bigger than 2.5mm) Drilled the hole 10mm deep slowly and with oil lubrication... Afterwards made the M3 threads inside the hole with a threading tap. And removed the leftover metal seen on image 3 with an m4 drill bit. Bought a new M3 stainless steel screw and cut to 16mm as the condenser holder piece is 8mm thick. It turned out to be 7mm long which is just right. Screwed it inside and glued with a drop of universal glue, with the untouched piece facing outside...
Now I have a new old screw it works great

The other part is removing the leftover screw from the hole in the condenser holder. It is easiest to remove it by bringing it to the jeweler or someone else who has a laser cutter. You can do it with a drill by yourself if your precise and careful not to damage the threads...





Here it is:

[Hobbyst46]

Admirable job !! Bravo ! glad you solved this.
The Zeiss is a precision-made scope. Namely, each of the screws, whatever its dimensions, fits precisely as is, no alterations are allowed...
To aggravate things further, there are tiny lock screws and set screws, reminiscent of old mechanical wrist-watch screws, almost everywhere, including the swing-out parts of the condenser and in other places. Having ignored or missed those once or twice, I broke parts. Over-engineering took its toll.
One must apply the minimum amount of manual force - easier said than done.

[imkap]

Admirable job !! Bravo ! glad you solved this.
The Zeiss is a precision-made scope. Namely, each of the screws, whatever its dimensions, fits precisely as is, no alterations are allowed...

Thanks...

It is very hard to find the spare parts, so it's best to repair... I'm very happy with the result as it makes no difference from the original.
There are a lot of small set screws, each has a purpose and age has gotten them. There were 2 stuck on my condenser so I went to the laser jeweler and he removed them, I could not find the replacement so made set screws out of normal screws I found at my uncles place...

I thought to buy new ones, but the watch and goggles repairmen say they are too big for both of them... I'll try to find online maybe... The sizes are 1.2 1.8 i think

[imkap]

With the help of this post on the mikroskopie-forum.de, I have successfully disassembled and removed all the problems that were affecting the coarse focus of my microscope. I wanted to do it without touching fine focus as it was working perfectly and it is prefectly possible. Only thing I removed and cleaned is the shaft for fine focusing. I'll write this for future reference of anyone searching the internet with the same questions as I did

https://www.mikroskopie-forum.de/index.php?topic=9401.0

The instruction provided is great and easy to follow. The only problem I got was when I needed to remove the focusing wheel on the left side, the one without the 'breaking' mechanism. The tool the original poster is using (image 24) had me believe that there were threads on the inside of the wheel, so I was a bit afraid not to break anything as my tool had m10 thread which is far too different and might damage the RMS threads inside, but it turned out that it was just stuck inside no threads . I think it wasn't just the old grease causing the problem with the removal as when cleaned up I couldn't easily put it back inside fully. The ring was somewhat conical at last 2-3mm the ring is at 0.3mm narrower. Not sure if this was the original design or it deformed in time, I realized I could hit it with a hammer to put it back or squeeze the 2 parts in a vise, but didn't do this as it seemed risky. So I have sanded the inside of the ring with a Dremel sanding red stone thing of just right diameter not sure how it's called, 1000-3000 grit paper and later polished a bit until I got the right result.

The other thing I'd like to note is that you can remove the full wheel assembly by unscrewing the 3 screws before disassembling the 3 wheel parts, it might be easier if it is stuck to bring the parts somewhere else to dissasemble. It is impossible to get to those screws with a screwdriver, so I cut a piece of a bit as shown on the picture and you can unscrew easily like this. Carefully not to damage the screws...
Of course the 2 hole bolt holding everything should be removed first. I used some pointy pliers for this application. It was very hard to remove one of the bolts so I scratched it a bit...

The only grease I used was ATE Plastilube which I think is great, it is a grease used for car breaking mechanism and is recommended by Alan Wood in an Olympus repair manual. Thanks for that...

Sorry this post is a bit confusing, I'm not a native English speaker and also forgot to record images But I think it will be much less confusing and provide some help for anyone holding the piece in their hands...

[imkap]

I have disassembled the stage a month ago and couldn't get it back right after at least 10 attempts I just couldn't center the Y, it would wiggle right to left with any a bit hasty moving. I've decided I'll leave it the best I can as it was very usable even like that.

But due to Covid isolation I'm experiencing now , I had some time to fiddle with the microscope so I realized what the problem is... I have placed the dowel pins not all like on this picture, but some of them facing the other side, not all on the same side. Now the stage works great. Not sure is this the original design, or my pins have worn out so this is the temporary solution. Also I have squeezed the one rail which isn't fixed with the pins to the inside. Now the stage works perfectly. I have had better results with less grease in the system...

This might not seem like much, but it was a revelation to me

[Hobbyst46]

Bravo again !

Yet i have to ask, the German forum post you mention seems to describe the focusing mechanism of the WL, not GFL (IMHO) and AFAIK they are not the same.
At least the fine focus of the GFL is a very delicate and apparently uncommon design - and difficult to repair if stuck.

Repair manuals for Zeiss are either very rare or do not exist; so any contribution on this subject is highly welcome !

[imkap]

Yes, it is a WL. Coarse focus is the same on both. I have peeked inside to see that fine focus on GFL has a few gears on the 'floor' of the housing which are connected to the spring on the front somehow. I cannot see that on pictures of WL, that part does look delicate but there was no need to touch it. It works perfectly, so I took your advice on not touching it. But I think if it starts misbehaving it is best to repair before something breaks.
If the gear lubrication is the only problem, I think one could try to clean without disassembling.

The shaft connecting 2 fine focus wheels is the same on both scopes. The front part where the stage holder connects is smaller on GFL but I think it is very similar. I think one could be able to get it right with enough time, patience and caution. The main problem is that any parts for this scope are seldom found and/or too expensive.
After doing all this I think I won't need to touch it for years...

Hobbyst46 I suppose you might know all this but I'll write for reference of the ones who don't. As I didn't know a month ago and couldn't find online.
Fine focus has limiters so you don't go too far up or down. There is a bolt on the shaft which moves until it reaches the limit. If you turn the fine focus to the end on either side to reach the limit and after turn the big wheel together with the fine focus wheel in the same side, the limit will also move and then the fine focus goes too far. This can result in the whole fine focus / stage / condenser assembly falling down and bumping quite hard to the floor. Nothing bad happens, but it was a huge shock to me when it first occurred some time ago. I was certain I have ruined everything and after looking inside I thought I saw a tilted gear Later I realized it was all in order My son was so angry, he was shouting: "I knew you'll ruin it. It was good when it got here, whyyyy!"

After that happens the limits are no longer positioned right, so they need alignment again. You can feel that when the fine focus end is not a sharp tick but has a mellow feel of the spring strain. It is visible on the image when on the end of the focus range the focus doesn't move. It can be aligned again by turning the fine focus the other way around and then turning both the big and small wheel together in this direction to go over the limit again on the other side. Then going back and checking if the tick is back and repeating the process if needed... If completely falls, you need to repeat maybe 6-7 times.
It is easier when the microscope arm is removed as you can then move the big wheels as much as you want and you can see the limiter bolt coming and going...

[Hobbyst46]

Hobbyst46 I suppose you might know all this but I'll write for reference of the ones who don't. As I didn't know a month ago and couldn't find online.
Fine focus has limiters so you don't go too far up or down. There is a bolt on the shaft which moves until it reaches the limit. If you turn the fine focus to the end on either side to reach the limit and after turn the big wheel together with the fine focus wheel in the same side, the limit will also move and then the fine focus goes too far. This can result in the whole fine focus / stage / condenser assembly falling down and bumping quite hard to the floor. Nothing bad happens, but it was a huge shock to me when it first occurred some time ago. I was certain I have ruined everything and after looking inside I thought I saw a tilted gear Later I realized it was all in order My son was so angry, he was shouting: "I knew you'll ruin it. It was good when it got here, whyyyy!"

Yes, it is all very familiar. Including the shouts, not from another person but an inner voice within me, about unjustified tampering...

Again, it is great that you managed it all.

[mikemarotta]

After a week of cleaning and greasing, with the advice from generous forum members ...

The shaft connecting 2 fine focus wheels is the same on both scopes.

Congratulations on the recovery of a beautiful old fine instrument. And congratulations also on your mechanical skills.

I translated materials from German to English for Zeiss and a couple of other German firms. I am not volunteering, but I will suggest that lately, I just put things into Google Translate and then if I have a specific technical question, I turn to a subject matter expert or just dig further in other references (dictionaries,technical treatises or whatever).

The thing with the Germans is that they will tell you exactly what you need to know, never any less but never any more.

Best Regards,
Mike M.

[EYE C U]

does the stage go up high enough?

[imkap]

After a week of cleaning and greasing, with the advice from generous forum members ...

The shaft connecting 2 fine focus wheels is the same on both scopes.

Congratulations on the recovery of a beautiful old fine instrument. And congratulations also on your mechanical skills.
I translated materials from German to English for Zeiss

Thanks

[imkap]

does the stage go up high enough?

I'm not sure I understand the question, it moves up and down for fine focusing as it should.

[imkap]

I received the "Grundkorper" extension and it looks great on the first glance. Optics seem quite clear and everything moves as it should. I just got back from a trip so I'm kind of dizzy, but it all seems to work fine. My GFL grew up a bit, I have a trinocular now...
I understand that different prism positions direct light to different holes, but not really sure what to do with all the options, except for the obvious. I also received something that looks a sort of a projective eyepiece (seen on the first image), but not sure how it was supposed to be used. If anyone knows what is it I'd really appreciate the info...

The GFL seems to be handling the extra weight quite nicely, the course focus actually works even better... So that is great.

[imkap]

I have just realized the 'projection' thing can be disassembled and found a Zeiss Winkel KPL 16x (dirty, but not delaminated)... The other part has a mirror and a small hole.

EDIT: I think I know... I fitted a Jena projective eyepiece into this and now it easily projects the image on the wall or on the table. I think this might be used for drawing... Nice

[BramHuntingNematodes]

What is that brass lens there, some kind of antique Leitz apo?

[imkap]

What is that brass lens there, some kind of antique Leitz apo?

Yes it is, I got it with my Reichert scope... It is a number 3 (10x)

EDIT: I don't know whether it is an APO or no... But it is a Leitz

[Hobbyst46]

The 16X eyepiece IMHO is not great because of the narrow FOV. The field number is probably 10, although there is a KPL 16X with fn=16.
But, maybe Rolf Vossen has found that it can be hybridized with a different KPL, to create a photography eyepiece.

[imkap]

The 16X eyepiece IMHO is not great because of the narrow FOV. The field number is probably 10, although there is a KPL 16X with fn=16.
But, maybe Rolf Vossen has found that it can be hybridized with a different KPL, to create a photography eyepiece.

Yes, I looked through it and it is really narrow... I thought about that maybe I can combine it with a 8x or something.. I'll experiment...

[Zeiss mensch]

Hey hi,
There is a manual in English entitled; "Zeiss STANDARD Microscope GFL".
Along with another " Operating instructions for the WL and GFLs".
The multitude of components for bright field, dark field, and phase contrast work are catalogued;
eye pieces,
objectives Achromats, Plan achromats, Neofluars, Apochromats, and Plan achromats
nosepieces, mono - quintuple revolving nosepiece. monocular - binocular tubes
All components have The 6 digit catalogue numbers i.e.; 46 52 52.
I have the 654-633 model.
65 = standard base with built in lamp and condenser.
4 = tube carrier with quintuple revolving nosepiece
63 = large rectangular stage 50mm x 75mm travel
3 = inclined binocular photo tube
added; Phase contrast condenser 0.9 NA w/swing out lenses IIZ
Hopefully these and 20 other Zeiss publication for these scopes are still available.

[imkap]

Hopefully these and 20 other Zeiss publication for these scopes are still available.

Yes, there are some Zeiss catalogues and instruction manuals available on the Internet. They also have an archive with a lot of publications. It is unfortunate that there are no repair manuals publicly available for Zeiss microscopes...