Old Toolmaker's Microscope

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PaulFurman
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Old Toolmaker's Microscope

Post by PaulFurman »

I got a crusty old toolmaker's microscope for $100 yesterday to play with, from a local machine shop that's closing down. He got it with some other stuff he wanted in a lot sold together. It weighs 172 lbs, the focusing arm alone is 45 lbs. About a 14x20x6 inch base. It's quite a white elephant. The only markings are on the lighting power supply which googles up around 1970 for PGH Rundfunk-Fernsehen Niederdorf (Erzg.) power supplies. No other markings I've seen.

If nothing else, I should be able to get stable high mag stacks by placing my old rig on the stage.
Time for a 20x or 40x objective.

The Bad:
-----------------------------
The z axis only has coarse focus.

A box of parts with the light from below was lost. A bulb from another light was out, and I guess I burned out the 4-bulb ring light while testing at the shop?

The bottom lighting apparatus with a mirror appears to have an aperture whose blades have tangled and ripped apart (some mangled blades fell out when I disassembled it.

It has a 3x lens that's not very good. I tried it on a bellows.


The Ugly:
--------------------------
It smells like grease.

It's heavy as heck.

It has an awkward eyepiece with a second goniometer eyepiece for measuring angles that gets in the way.


The Good:
--------------------------
It's sturdy.

It has a spectacular 8-inch round glass stage with x,y positioning and 360 rotation (rotation is stiff).

Two huge micrometers with crank handle knobs, they extend about an inch with 0.0001 inch ticks (2.5 microns). The stage has this clickety-grind geared spring-loaded setup that's pretty slick. It moves another 6 inches in the x, another inch in the y axis, presumably you just use blocking to extend the micrometer for that.

The focusing arm tilts (an odd feature).

Image

That's my current bellows rig in back, showing goniometer stage, my lighting diffuser plastic arch with pecpads laid on top and a 12 lb threaded rod laid on it for stability.

At left is the power supply for the lights. Lower right is the ring light and the bottom lighting mechanism removed, including broken bits of aperture blade from inside that.

Notice the blue and yellow pencils holding the stage open against the spring mechanism showing the full travel of the stage.

lothman
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Post by lothman »

looks like Carl Zeiss Jena from Eastern Germany. A similar but certainly older model is decribed here:
http://www.mikroskop-online.de/Mikrokop ... gmikro.pdf

found some more links:
http://translate.google.de/translate?hl ... D53&anno=2
it seem to be the "Großes Werkzeug-Mikroskop DS"

you might also find some literature from zeiss archive
http://www.archive.zeiss.de

and search there for "Werkzeugmikroskop"
Last edited by lothman on Thu Jul 22, 2010 12:49 pm, edited 2 times in total.

Planapo
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Post by Planapo »

I see no pic.
(Erzg.)
means Erzgebirge, a mountainous region in southern Saxony at the border to the Czech Republic, so it's former GDR, East-German made.

--Betty

edit: Ahh, lothman was faster. Now I see a pic. That does look sturdy! And Paul, you seem to be quite a sophisticated pencil pusher there! :) :wink:

ChrisLilley
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Post by ChrisLilley »

Wow, what a fantastic find (and price)! As long as you have space for the thing, it should give excellent results.

About the z-axis - have you considered putting a z-stage with an ultra-fine micrometer onto the main stage, using the scope coarse focus for initial setup, and then moving the sample on a z-stage for stacking?

Heavy as heck is a good thing, as long as you can get it home (apparently accomplished) without putting your back out.

PaulFurman
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Post by PaulFurman »

lothman:
Thank you! So it *is* a decent piece of equipment, although I'm struggling with how to make use of it for macrophotography. That does look like a very similar design.

Here's the same model Carl Zeiss DS Large Toolmakers Microscope from your links. I've asked the seller for a copy of the manual.

Here's an automated English translation of the older model's manual:
The measuring microscope is supported by a strong arm, which means Pinion in height can be adjusted coarsely. The stand is in the Longitudinal direction at a height of the peak level lies in the axis tilt. The fine height adjustment is done by raising and lowering of the microscope with a star-shaped nut.
OK, that must be the scalloped ring where the lens mounts. It is extremely stiff from dried grease or perhaps a set screw I haven't found.
At the microscope tube is located above a Prism box to accommodate the different eyepieces with eye piece. The hole with clamp screw on the prism box is used to attach the Projection device or the photographic device.
Hmm, OK I got the big awkward goniometric eyepiece off and there's a 1-1/4-inch opening where a camera could be attached at a nice angle.

Betty:
I found similar power supplies on the web with (Erzg.) & (Ostd.).

Chris:
Yes, I got it home and up 3 tall flights of stairs without injury, just lots of huffing & puffing and some sore muscles. I hope I can figure out a way to make it do more than push pencils!

Choronzon
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Post by Choronzon »

Paul, that thing rocks, man. Notice the azimuth adjustment that tilts the column left or right. (look, I made a funny) Aus Jena made some awsome products that were imported under that name, but Zeiss Jena in their country of orgin. There must be some way to adapt it to macro-micro use. For $100 there's no way to lose, unless, of course, you're married, then you need to be creative. Enlisting my youngest child into scientific servitude has worked for me. so I'll continue to go with that angle. :lol:
I am not young enough to know everything.

g4lab
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Post by g4lab »

Yeah definitely don't let the warden see that one. Sneak that into the fun room in the dead of night. :lol:

You could sell it to a gemologist for measuring angles on cut stones for which that goniometric ocular would be outstanding as would the stage.

Somebody paid good money for that unit once. Its fun to get things like that for change.

PaulFurman
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Post by PaulFurman »

Some details.

Huge (penta?)prism inside the eyepiece assembly. This shows horrible rainbow diffraction. Every segment of the optical path has some lenses in it so that could be part of the reason the lens didn't perform well on a bellows. The orientation here is the focus arm removed and laying on it's back.
Image

Here I've removed the prism box, viewing from the opposite side, looking up at the lens mount. That black scalloped grip should do fine focus but it's extremely tight On the side you can see an odd screw with two holes so you'd need a fork shaped screwdriver head
Image

This shows a futile attempt to unscrew that 2-hole head with a wire clip held in pliers. And the next set of screws under that ledge which I cannot loosen because I can't get a regular screwdriver in and they are very tight.
Image

Overview of the focus arm, showing the tilt feature and an arm below for holding the bottom-light parallel to the lens below the stage. It reads "12804 - Height of centres 1,7161 in". The knob at lower-right is for adjusting tilt but there are a pair of set screws that need to be completely removed to allow tilts.
Image

Bottom.
Image

PaulFurman
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Post by PaulFurman »

Jammed Fine Focusing Mechanism

I don't understand this. It sort of looks like brake pads but I'd need a flat head screwdriver bit on a ratchet wrench to loosen those big black set screws that are angled out deep inside.

The cylinder it presses against doesn't turn when I rotate the black scalloped focus ring but the cylinder should slide somehow given the springs. The focus ring will only forcibly go about 1/10 of a turn. I don't see anything else turn along with it; inside or out.

Loosening the set screws at the top of the 'brake pad' fork had no effect. Those are set screws with set screws!

The two-hole/spanner-wrench screw heads on the sides that I mentioned previously just hold springs which sounds more like a ball bearing mechanism than a helix? Or maybe just a way to keep the lens from rotating with the helix.

The next thing I see that unscrews is the optical tube on either side requiring spanner wrenches that I don't have. There is no glass in this segment so for a camera mounted, this is all I'd need.

Image

[url=p://www.flickr.com/photos/edgehill/4820493650/sizes/o/]Image[/url]Image

ImageImage

g4lab
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Post by g4lab »

The color rendition on your later pix confirms the "aus Jena" , Zeiss east Germany origin of this unit.

Zeiss would issue a list of all the tools required for each instrument to be serviced if field service was supposed to be possible. I would bet that for many of the adjustments you are trying to work on the service manual would state words to the effect of "Field service forbidden! Factory adjustment only"

They still have instructions like that in many field service manuals. I have several contemporary ones. For example collimation of of binocular heads is not done in the field.

All the microscope manufacturer's had particular tools some of which could be bought by dealers and others only for internal use. You are running up against the difficulty of finding or substituting such things.

The main categories are pin wrenches and barrel grippers. Some of the concentric locking nuts (aka jam nuts) can have unusual patterns.

There are several adjustable pin wrenches available on fleabay and they are much lower priced than they were back in the day when you could only buy them from Edmund scientific or Colorado Camera Repair.
search "camera wrench" or "pin spanner" Beljan has a very nice one but its $70.

It is very important to have screw drivers that fit the slots perfectly. A screwdriver is cheap and expendable. You grind them to fit and then harden them in Kasenit. Of course this may or may not pay if you have only one example to work on.

Unlike Japanese equipment which sometime uses thread locking and lacquer type materials to help with locking east German Zeiss used techniques that actually were left over from pre War Zeiss designs.

These involved a great deal of feinmechanikbau which includes techniques of fitting things together with tolerances you would not believe possible and tightening threaded fasteners to a degree that is difficult to duplicate in the absence of the exact holding jig and tool tip made by a skilled tool and die machinist a couple of machines over.

It probably has no name on it because it may have been imported into the US illegally before products from the former east Germany were allowed here. Zeiss west Germany owned the Zeiss trademarks in the west zones which was a separate obstacle to importation.

Using that wire clip handle as a pin wrench is a brilliant idea. That wire is drawn and hard. Just make sure the ends are squarely ground and parallel so they don't try to jump out.

I am sure Choronzon will have something to add too.

PaulFurman
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Post by PaulFurman »

PaulFurman wrote:Loosening the set screws at the top of the 'brake pad' fork had no effect.
When fully loosened, the fork rotates very stiffly along with the rest of the optical tube - except the part where the focus ring is attached. It doesn't budge in the direction of focusing though.

The dark brown grease inside on the main cylinder is dried up and gummy but not enough to stop sliding or rotating much... pushing on... I think that may actually be the problem. If I keep forcing the focus ring, it will gradually turn more... yep, a few drops of motor oil and a gallon of elbow grease got it rotating 5 turns and 5mm of focus movement. It looks like it ought to move more like 30mm but nope, even after repeated attempts to loosen, only 5mm. I suppose that's good enough for very high mag stacks.

Well, I've got it more or less functional now. I was able to thread a t-mount flange ring onto the eyepiece and a temporary glued RMS thread on the bottom. It works out to about 190mm (175mm possibly) from sensor to RMS. This ought to completely eliminate any concerns about vibration!
The next thing I see that unscrews is the optical tube on either side requiring spanner wrenches that I don't have.
Inside the focus ring, there's a spanner wrench fitting that rotates separate from the focus ring. I can turn that a little with a 12-inch pipe wrench after removing the focus ring to get room to grip it, and that rotates the fork when the set screws are loose.

The other end has a spanner wrench fitting with 2 shallow drilled holes and I can grip that with the pipe wrench too but it doesn't budge other than rotating the whole tube and fork.

PaulFurman
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Post by PaulFurman »

It works! at 12x with a 10x objective. I'll do more testing this evening...

ChrisLilley
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Post by ChrisLilley »

Paul, it is fascinating to read your blow-by-blow description and to see the photos as work progresses. Thanks for documenting this.

PaulFurman
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Post by PaulFurman »

Chris, I figured I'd better take pics in case I couldn't remember how it went back together and the detailed descriptions helped me sort it out in my mind. Hopefully useful for future use too.

Thanks g4lab! (and all). I probably made a mess of the proper calibration by loosening every screw I found but oh well. I am awed by the fine craftsmanship and clever mechanics. The focus mechanism with 'set screws for the set screws' works by making a loose connection from the fork to the guide rod above. I just wish it had more than 5mm of movement :-(

The coolest part is the clickety-grind spring loaded focus mechanism: [edit: not focus but the x,y stage movement] as you twist it back, it makes a solid click every so many turns and when released, it glides back so smoothly over 30 seconds with a brilliant robotic whirring grinding sound :-) The x,y stage is truly a pleasure to use compared to my old stiff micromanipulator parts. It's also very nice to be able to make stacks without looming concerns about vibration with such a solid rig. It still vibrates when walking on the floor but the whole thing moves together and there's no chance of a little shutter movement messing with the connection from stage to lens.

That said, there are serious limitations to this rig.

As you can see below, the tube does not accommodate full frame 35mm field of view. It wouldn't be easy to remove the obstructing parts. I think I'll abandon that whole thing and add a microscope focus block. In an ideal world that would mean cutting back the long square extension tube and figuring out a way to mount to that sawed edge, and add a bellows for adjusting magnification. Bellows are a lot less stable but if they aren't making the movements, it might be safe to add to the system.

Here's full frames or some tests. Subject is grass flower (stamens?).

left: Stack of 95, 10x 0.25 NA MI 210 tube at 2 sec +27.5mm extension D700 (ran out of room to finish)
right: Stack of 121, N Plan 10x 0.30 NA 160 tube at 2 sec D700 (8 micron steps, 1mm total) at 12x

Image Image

full crops:

Image
Image

I think the N-Plan image looks better than the Michelson Interference but it's .30 NA vs .25 also.

Here's the rig set up with camera mounted and extension tubes to make 20x. Note the subject has to be raised since it's designed to focus at the rotation point for the arm, an inch & a half above the glass stage. I used a ring of pec pad tissue for a diffuser and you can see the overhead projector that I used for illumination as well as my old bellows rig.

Image

PaulFurman
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Post by PaulFurman »

Another rambling discussion with myself as I sort out how to use this thing...
PaulFurman wrote:Bellows are a lot less stable but if they aren't making the movements, it might be safe to add to the system.
Well, I removed the head and noticed a 1/4" tripod bolt thread on the side to mount the bellows and it seems to work pretty well. Much more stable than the old wood bellows rig at least. For now I'm using the old micrometer on the bellows for fine focus stepping and frankly it works better than the microscope helix.

What really needs to happen though is the arm cut off flush 5 inches back so the bellows points at the center of the stage. With it pointing at the far corner, the rotating stage is useless, and it was real handy when I used it centered (although the grease is dried and it only moves about 15 degrees).

If I adapt a microscope focus block, that looks like another 3 inches or so, which means there's no room for a bellows if I want to keep it centered <sigh>. So a focus block means inventing something. Maybe the PN-11 52.5mm extension tube shown with tripod mount and stack tubes or one of those focusing helicoids.I suppose the way to go then is simply mount the camera tripod base and hang the helicoid from the camera. Either way, the camera controls are going to be upside down.

I wish I could use the original head, with the 45 degree angle but I've been unable to unscrew any more of it and I would need to remove some parts to avoid vignetting. Also, I'm not sure what that pentaprism will introduce as far as CA is concerned. It looked bad with bare eyes.

Image

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