William Gaertner Toolmaker's Microscope

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John W. Briggs
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William Gaertner Toolmaker's Microscope

#1 Post by John W. Briggs » Mon Aug 23, 2021 11:34 pm

Hi Folks--

I am new to this forum, and my specialty is telescopes. But who can resist microscopes? My wife and I have two ponds (surprisingly) here in the high desert of New Mexico, and we're increasingly active exploring pond water and what swims in it.

But it suddenly occurred to me that people here would forgive me showing off an eBay microscope purchase I made about two years ago -- a really nice William Gaertner Company toolmaker's instrument! We have a few standard and common lab microscopes here, like our Bausch & Lomb flat-field DynaZoom made about 1968. We just got the DynaZoom (in great shape), and we're presently waiting for replacement bulbs for the illuminator. Our excitement over the DynaZoom accounts for my joining this forum today. (And in another post, I accidentally called our DynaZoom a "Dynoptic," but ours is in fact the DynaZoom model, with a head including the option for photography.)

Anyway, the attached image shows the elaborate Gaertner instrument that I have in my instrument lab, mainly for working on telescope parts. It allows very accurate measurement of screw threads, cutting-tool angles, etc. Some very old instruments have completely non-standard threads, and having the ability to measure them was my rationale for getting the Gaertner. (Also, I simply loved it. I can't deny it! I'm sure there's sympathy here.) It wasn't cheap, but it was nothing compared to its original cost that, if I understand correctly, would have been about $25,000 (!) in today's relatively worthless dollars. These instruments are not uncommon on eBay, but it's unusual to find one in good condition at a reasonable price, and also with accessories. I was lucky.

William Gaertner was closely associated with George Ellery Hale, an important early 20th century American astronomer, and he made all sorts of wonderful scientific instruments, including complete observatory telescopes, astronomical cameras, and related accessories. Astronomers refer to elaborate microscopes as "measuring engines." In those devices, extraordinary effort was put into the X-Y stage used for measuring glass-plate celestial photographs. I attach an image of a Gaertner measuring engine also in my collection, made circa 1918, that was originally used at Wesleyan's Van Vleck Observatory for measuring the tiny annual "parallax" shifts of stars related to their distance from Earth. Thus, the instrument you see -- fundamentally a microscope -- was quite literally used to measure the distance to nearby stars.

I love Gaertner stuff so much that I named my hound dog "Gaertner," much to the confusion of our veterinarian.

Our B&L DynaZoom is missing the screw-in cover for the camera port on the optical head. If anyone has a spare from a basket-case DynaZoom, please let me know! Also, I would also love to find a B&L camera adapter typical of what was supplied when the DynaZoom was new. The only thing we have to screw in the camera port right now is a longish, plain aluminum tube that evidently holds an eyepiece in the right position to check the image that will be seen by a camera.

With lots to learn about microscopy and about what swims in the water Gaertner drinks,

--John W. Briggs,
The Astronomical Lyceum,
Magdalena, New Mexico.
Attachments
Gaertner Measuring Engine.jpg
Gaertner Measuring Engine.jpg (74.17 KiB) Viewed 10611 times
Gaertner Toolmaker's Microscope
Gaertner Toolmaker's Microscope
Gaertner Toolmaker's Microscope compressed.jpg (134.83 KiB) Viewed 10611 times

PeteM
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Re: William Gaertner Toolmaker's Microscope

#2 Post by PeteM » Tue Aug 24, 2021 12:41 am

Your toolmaker's microscope looks wonderfully well equipped. Fairly rare to see one with centers, what looks to be a sine plate, and more.

microcosmos
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Re: William Gaertner Toolmaker's Microscope

#3 Post by microcosmos » Tue Aug 24, 2021 3:25 am

John, this is very interesting. Thanks for posting. I've never seen one before!

Could you explain briefly how this microscope measures screw threads accurately?

I have a regular (polarizing) microscope with a rotating stage that can measure angles to 0.1 degrees, with the regular eyepiece micrometer that measures lengths. I have both transmitted and reflected illumination. I'm wondering if I can use my setup to make some kind of screw thread measurements or is it completely hopeless at it. Glad for any advice or comments.

Metrology is one thing I find really fascinating.

BramHuntingNematodes
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Re: William Gaertner Toolmaker's Microscope

#4 Post by BramHuntingNematodes » Tue Aug 24, 2021 3:55 am

The Dynazoom flat field scope I am very familiar with. The triocular tube you describe would work well with a reducing lens. The original camera setup has a very large shutter, a helicoid and a lens at the top for various film formats. They aren't expensive.

I wouldn't mind taking a look at your Dynazoom if you get a chance. I think it's a remarkable.scope often overlooked. The flat field system limits objective choices substantially, but it's a very competent instrument nonetheless.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

BramHuntingNematodes
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Re: William Gaertner Toolmaker's Microscope

#5 Post by BramHuntingNematodes » Tue Aug 24, 2021 4:02 am

https://www.ebay.com/itm/Bausch-Lomb-mi ... 632-2357-0

This one looks complete although mounting the camera would still be up to you.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

PeteM
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Re: William Gaertner Toolmaker's Microscope

#6 Post by PeteM » Tue Aug 24, 2021 4:04 am

microcosmos wrote:
Tue Aug 24, 2021 3:25 am
. . .

Could you explain briefly how this microscope measures screw threads accurately? . . .
John can likely add to this. The measurement of pitch is pretty easy. Just have a reticle in the eyepiece (say, a cross hair) and use the x-y micrometer dials on the stage to measure the distance from pitch crest to crest. These will have been calibrated to read directly in a toolmaker's microscope such as the one John has. Major and minor pitch diameters can be measured in a similar way. Thread form is a bit trickier and often done in a comparator.

Should you want to do the same, almost any epi microscope can be fitted with an eyepiece reticle with cross hairs. Add some sort of graduated stage and measure directly as features traverse the cross hair center. If you want to measure directly from a reticle with scales (skipping the graduated stage), perform an initial calibration to establish what multiplication factor you might need for the optics at hand.

My own poor man's toolmaker's microscope consists of an x-y stage with digital readouts on it, sitting under a stereo microscope with a reticle in one eyepiece.

John W. Briggs
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Re: William Gaertner Toolmaker's Microscope

#7 Post by John W. Briggs » Tue Aug 24, 2021 4:42 am

Hi Again Folks--

I should not write as though I really know what I'm doing with the Gaertner toolmaker's, as I'm sure the experienced masters who seriously used these things back in the day knew much more than I'll have a chance to ever learn about it. Unfortunately I do not have a manual for it. I do have a good hardcover book on optical metrology that writes of the Gaertner specifically, and I can eventually post the name of that book (which is in my lab, three miles away, as I write).

One issue with these instruments is that the important accessories came in a separate wooden case. Almost always, the main microscope, even when surviving with its large case (as mine was), gets separated from the second box containing the accessories. But, all is not lost. Among the chief items among the accessories are clamps (and "centers") to hold parts. When an orphaned "accessories" box goes on eBay, most sellers have no idea what the parts are for. But the clamps and centers are labeled "Gaertner," and also with a key phrase, "Bear to the right." This phase refers to how to install the precision clamps in precision slots on the microscope. Thus, when seeking the accessories on eBay, use the keyword "Gaertner" and the phrase "Bear to the right." You will then find the accessories. There are two examples of orphan accessories on eBay right NOW!

Here are additional arcane details:
https://www.practicalmachinist.com/vb/m ... rs-252779/

You might, however, have to wait a bit to find an accessories set for about $100, as I did, rather than the ballpark $2,800 that some guy was stubbornly asking a couple years ago, and even until recently! (He looks gone now.)

The X-Y stage on the Gaertner reads to 1/10,000's of an inch as I recall. Measuring engines usually read to microns, i.e., about 2.5 times finer. Screws, cylindrical parts, and threaded parts can be held in the special clamps and centers (once you find the necessary accessories), and can be viewed in the microscope which is equipped with a very fine reticle. Further, the reticule includes line(s) that adjust in position angle for measuring thread angles, or the angle of anything else in the field of view. A variety of illumination is available, some of which (evidently involving contrasting colors of light) I don't understand yet. The inclination of the microscope can be adjusted considerably to the plane of the X-Y table. The table, also, is equipped for very precise and measurable rotation. A lot of the surfaces are scrapped like the "ways" on lathe beds and in high-quality machine tools.

The people who designed and built machines like this were more smart & much more experienced than I, I fear. (And I don't consider myself stupid!) ;-) Such magnificent devices!

Cheers--
--JWB, equally challenged by the full potential of his B&L DynaZoom, and wishing he owned a B&L 4x flat-field objective.

microcosmos
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Re: William Gaertner Toolmaker's Microscope

#8 Post by microcosmos » Tue Aug 24, 2021 5:14 am

Thank you Pete and John. I have a much clearer idea of what this involves.

I have a graduated stage and a reticle with both crosshairs and a micrometer scale. My stage is of course not accurate to a micrometer - the x-y dials have vernier scales down to 0.1 mm i.e. 100 micrometers. But the reticle can do better depending on the magnification.

The crosshair reticle in conjunction with my rotating stage will serve a similar purpose to a reticle with radiating lines which I imagine is the design used for angle measurement.

Assuming everything is calibrated.

My stage can't be inclined and there's no specialized clamp for screws and things like that, so that makes it much more difficult practically.

I might just try measuring some screws! I'll report back if I get to that and find anything interesting. I'm not that crazy about screw measurement, but I am interested in forensic microscopy and I can imagine situations where investigators have to compare screw threads and also measure defects and variations in the thread dimensions. But of course they will have the proper tools.

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#9 Post by MichaelG. » Tue Aug 24, 2021 7:22 am

Thanks for the posts, John

I also have a Gaertner … older and scruffier than yours, but the same design: It’s in the embarrassingly long queue of restoration projects.

One of the finest features of these Toolmaker’s Microscopes is that effective pitch of the measuring lead-screws is adjustable [for calibration purposes, not for routine operation]

MichaelG.
Too many 'projects'

PeteM
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Re: William Gaertner Toolmaker's Microscope

#10 Post by PeteM » Tue Aug 24, 2021 3:40 pm

MichaelG. wrote:
Tue Aug 24, 2021 7:22 am
. . . One of the finest features of these Toolmaker’s Microscopes is that effective pitch of the measuring lead-screws is adjustable [for calibration purposes, not for routine operation]

MichaelG.
Michael - you have me intrigued. Is that an adjustment to take up slack (perhaps a split bronze nut than can be adjusted tighter as needed in machine tools or a split collet in micrometers)? Or something else?

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#11 Post by MichaelG. » Tue Aug 24, 2021 5:52 pm

PeteM wrote:
Tue Aug 24, 2021 3:40 pm
MichaelG. wrote:
Tue Aug 24, 2021 7:22 am
. . . One of the finest features of these Toolmaker’s Microscopes is that effective pitch of the measuring lead-screws is adjustable [for calibration purposes, not for routine operation]

MichaelG.
Michael - you have me intrigued. Is that an adjustment to take up slack (perhaps a split bronze nut than can be adjusted tighter as needed in machine tools or a split collet in micrometers)? Or something else?
Very much ‘something else’ Pete

The lead-screw can be angled slightly from the operating axis of its slide [the nut is mounted in such a way as to allow this, without binding] … which means that the effective pitch can be tweaked. The screw forms the hypotenuse of a very acute triangle.

I should have some documentation ‘somewhere’ and will post some details if/when I manage to locate it.

MichaelG.

.
Edit: __ The execution is different but the underlying concept is similar to the wonderful Bryant Symons lathe:
http://lathes.co.uk/bryantsymons/
Too many 'projects'

MicroBob
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Re: William Gaertner Toolmaker's Microscope

#12 Post by MicroBob » Tue Aug 24, 2021 7:23 pm

Hi John,
nice instruments!
When having to measure dimensions that can't be contacted with mechanical measuring devices well a measuring microscope is indispensable. I don't have one at home so I have to get along without but having precise measurements makes things much easier. Start precise and the barely stay withing tolerance is easy work! :lol:
Especially measuring dimensions that are not in the same Z plane is fairly easy with such a microcope.
If you use it often, it might be an idea to buy one digital micrometer e.g. from Mitotoyo for the X axis, made for measuring microscopes. Being able to set zero at any position removes much calculation from the job.

Bob

PeteM
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Re: William Gaertner Toolmaker's Microscope

#13 Post by PeteM » Tue Aug 24, 2021 8:42 pm

MichaelG. wrote:
Tue Aug 24, 2021 5:52 pm
. . .
Very much ‘something else’ Pete . . .
Thanks, Michael. Very interesting implementation and new to me.

Was the Gaertner toolmaker's microscope from an era where they couldn't make near perfect micrometer threads and just be done with it? Or adjustable for some other reason?

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#14 Post by MichaelG. » Tue Aug 24, 2021 10:08 pm

PeteM wrote:
Tue Aug 24, 2021 8:42 pm
Was the Gaertner toolmaker's microscope from an era where they couldn't make near perfect micrometer threads and just be done with it?
If I recall correctly, that Gaertner design dates back to about 1920 … so, yes, I think that’s the answer.

MichaelG.
.

Edit: http://www.gaertnerscientific.com/company_info.htm
Last edited by MichaelG. on Tue Aug 24, 2021 10:14 pm, edited 1 time in total.
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PeteM
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Re: William Gaertner Toolmaker's Microscope

#15 Post by PeteM » Tue Aug 24, 2021 10:12 pm

Thanks, Michael.

John W. Briggs
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Re: William Gaertner Toolmaker's Microscope

#16 Post by John W. Briggs » Tue Aug 24, 2021 10:40 pm

I want to thank everyone very much for the discussion. I wrote another message last night, but I seem to have deleted it rather than to have sent it! Nematode Master Bram very kindly pointed out a camera adapter for my B&L DynaZoom Flat-field photo binocular, and I bought it right away! While I have some specialized things like measuring engines in my collection, my wife and I are excited to have the very recently acquired B&L just for some fun, old-fashioned microscopy. It's likely to prove the best instrument we have for pond water.

Regarding screws in measuring engines, etc., one fellow of great interest to me is Lewis Morris Rutherfurd, a 19th century astronomer in New York City who was significant in the development of more perfect screws and in the related matter of ruling diffraction gratings. Although it's rather rambling and never mentions microscopy once, I have a lecture on the Web that talks about Rutherfurd and how he and his early measuring engine were interesting, along with a lot of other optical history. It's presented, however, with an entirely astronomical bias. I did it a year ago as an invited lecture for SPIE, the society of photo-optical instrumentation engineers. It also features the entirely ridiculous and informal museum/library I operate here in New Mexico. For your consideration:

https://vimeo.com/451287860/e8c9ac6db3

Like visiting my "Astronomical Lyceum," watching the video is free. Anyone sympathetic to instruments in general should be amused. --JWB.
PS: Beware, I am not even a member of SPIE.

PeteM
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Re: William Gaertner Toolmaker's Microscope

#17 Post by PeteM » Wed Aug 25, 2021 1:18 am

Thoroughly enjoyed your video, John. Bravo for assembling your lyceum.

I suspect you'll find Michelson's quote also applies to microscopy. These equally astounding images lend a deeper understanding of all life and the world around us.

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#18 Post by MichaelG. » Wed Aug 25, 2021 7:30 am

John,

I have just taken the liberty of sharing your ‘tour’ on the Model Engineer forum … Several people there should be interested.

Well done Sir !!

MichaelG.
Too many 'projects'

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#19 Post by MichaelG. » Wed Aug 25, 2021 8:28 am

Sorry I don’t have any more details, but here’s a photo from the ‘family history’ showing my Dad posed at the toolmaker’s microscope … I believe it is late 1950s and was showing-off a new acquisition by the technical college at Aston, Birmingham, England.

MichaelG.
.
7B482092-75D9-4682-9440-F76D17D04DF4.jpeg
7B482092-75D9-4682-9440-F76D17D04DF4.jpeg (150.68 KiB) Viewed 10433 times
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MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#20 Post by MichaelG. » Wed Aug 25, 2021 10:28 pm

I think this may be of interest: http://adsabs.harvard.edu/full/1944PA.....52..442H

If you haven’t used adsabs before; note that the whole article can be downloaded in pdf, by clicking the ‘Other article options’ text, then scrolling to the bottom of the page and clicking the ‘Send PDF’ button.

… it’s probably their idea of an initiation ritual :geek:

MichaelG.
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Hobbyst46
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Re: William Gaertner Toolmaker's Microscope

#21 Post by Hobbyst46 » Thu Aug 26, 2021 11:02 am

MichaelG. wrote:
Wed Aug 25, 2021 8:28 am
Sorry I don’t have any more details, but here’s a photo from the ‘family history’ showing my Dad posed at the toolmaker’s microscope … I believe it is late 1950s and was showing-off a new acquisition by the technical college at Aston, Birmingham, England....
Classics and class...awesome. I think that the love of microscopes is most of all due to their being precision instruments.
BTW, what is inside the glass show box that hangs on the wall on the left ? many circles arranged in a vertical row ? are these the dials of instruments ? or medals of honor ?

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#22 Post by MichaelG. » Thu Aug 26, 2021 11:16 am

Hobbyst46 wrote:
Thu Aug 26, 2021 11:02 am
BTW, what is inside the glass show box that hangs on the wall on the left ? many circles arranged in a vertical row ? are these the dials of instruments ? or medals of honor ?
I wish I knew … unfortunately that is the only scan of that photo that I have seen.

MichaelG.
Too many 'projects'

eKretz2
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Re: William Gaertner Toolmaker's Microscope

#23 Post by eKretz2 » Mon Aug 30, 2021 3:50 am

The wall hanging almost looks to be a display case full of grinding wheels and sharpening stones. Was your father in a machine shop related area?

PeteM
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Re: William Gaertner Toolmaker's Microscope

#24 Post by PeteM » Mon Aug 30, 2021 4:16 am

Interesting idea. Norton Abrasives in the UK, as much as anyone, made a science of grinding.

MichaelG.
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Re: William Gaertner Toolmaker's Microscope

#25 Post by MichaelG. » Mon Aug 30, 2021 6:55 am

eKretz2 wrote:
Mon Aug 30, 2021 3:50 am
The wall hanging almost looks to be a display case full of grinding wheels and sharpening stones. Was your father in a machine shop related area?
Thanks for your interest

Aston [Gosta Green] was the first designated “College of Advanced Technology” in the U.K.
https://www.aston.ac.uk/about/history/timeline

My father was a Technician/Instrument-Maker/Tutor there … but I was too young to really appreciate what his job involved.

I’m guessing that photo was taken for a newsletter or some-such … If I ever get a better copy, it may solve the mystery.

MichaelG.
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Sure Squintsalot
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Re: William Gaertner Toolmaker's Microscope

#26 Post by Sure Squintsalot » Sat Jul 02, 2022 12:31 am

Having worked in my father's tool and die shop as a kid, I never saw or even heard of a "toolmaker microscope" until I saw them on ebay recently.

Then I saw the hooded projection screen in the photo above and realized that these microscopes must have been progenitors of the modern comparator, of which we had three or four on the shop floor:
images (1).jpeg
images (1).jpeg (63.72 KiB) Viewed 7066 times
The optics are designed to cast a profile image on the screen; graduated lines and radii make it possible to directly measure dimensions, angles, and curved profiles (these being most important). The curved profile must be cut into one of those Norton abrasive wheels using a diamond tipped radius cutter. The curved profile is then ground into a piece of carbide steel which makes up some part of a progressive die.

This is very delicate and difficult work, requiring enormous skill and patience, all of which went down the toilet with the introduction of the CNC Wire EDM. All of that exquisitely made machinery and measuring equipment of yore sold, essentially for scrap steel.

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