The making of Monoculus

Jay Holmes

Monoculus and bagFigure 1: Monoculus with felted bag

My microscopical journey started at home with my sister’s Bausch & Lomb microscope, looking at copepods from the nearby pond. That was MANY years ago! In the intervening years I used microscopes in high school for studying fossil woods, in college in so many geology courses, and in analyzing building materials for asbestos. But the copepods always drew me back.

As I explored my interest in microscopes (a few decades later) I read Dr Brian J. Ford’s Single lens: the story of the simple microscope and was thrilled by these compact microscopes and their uses in botanical and aquatic discovery. I acquired a couple single lens microscopes and found them a joy in the field. Continuing to read about lens making and metal work, the Internet is a wonderful thing, I became interested in trying this out myself. I ran across a helpful machinist from Canada who wrote for The Home Shop Machinist magazine, Sandro Di Filippo, who offered to help! The Internet is a wonderful thing again! This turned into an international collaboration! I shared some ideas I had on using a blender base as a motor and putting a lens lap on the spindle. After some design tweaks Sandro made a lens lap and sent it international post! The experiment was a success and I had a lens! Now I needed to learn some metal work and Sandro coached me through that as well! He suggested a wonderful lathe, a Sherline, and I then went about designing a microscope that I could machine as a novice. I would sketch in my notebooks, and then draw each machining step in my computer and often through that process figure out where I would get stuck before I had ruined a piece of brass, although that did happen once in a while. Sandro rescued me a few times.

Stage mount sketchesFigure 2: Stage mount sketches

Stage mount drawingsFigure 3: Stage mount drawings (Click the image for a larger version)

From first lens to finished microscope with one lens was about two years of about one evening a week if I was lucky. I wanted to protect my wooden box so I wrapped it up with a needle felted bag. All along the copepods were dancing in my head. So when I got to the felted bag I added a felted copepod on the outside (Figure 1), and I then tucked a little piece of red velvet down into the brass mount on the lid in honor of the red eye of the copepod. I have been calling my microscope “Monoculus” after those copepods and for its single lens design.

Lathe and MonoculusFigure 4: Lathe and Monoculus

Monoculus in wooden boxFigure 5: Monoculus in wooden box

After using the tall aluminum and iron lens grinding and polishing laps (back left of Figure 6) on the blender motor, I was ready for something a little slower… The web site for Museo Galileo had an interesting little video on lens-making which caught my eye, but I had to figure out the mechanics of it all. I had a treadle sewing machine table that I was using for my work bench but I was not good enough at machining to make gears. Then someone gave me a copy of a kids book called How things work and as I was flipping through it I saw an illustration of an “eggbeater drill” as we used to call them and I saw the gears at 90° angles and that was it! I jumped on eBay and got a couple old drills and the treadle-powered lens grinder and polisher in Figure 7 was born! With my own lathe now, I modified the lens lap design to thin discs of cast iron for grinding and maple for the polishing process, and made a bracket for holding these discs on the drill where the handle would normally go.

Collection of lapsFigure 6: Collection of laps

Treadle-powered lens grinder and polisherFigure 7: Treadle-powered lens grinder and polisher

For this treadle lens I wanted a historical twist. I live down the street from the cemetery where John James Audubon is buried, so I went out hunting for some street glass near the monument to this naturalist, he was mostly interested in larger organisms, but it was a fun idea anyway. I found this nice piece of glass on a drizzly day, Figure 8, and took it home, and with a lot of foot work on the treadle, produced the lens in Figure 9. It magnifies at about 50× using the technique described by Dr Keeling of the University of British Columbia in DIY Microscope. So now Monoculus actually has two eyes, but only uses one at a time.

Glass in the streetFigure 8: Glass in the street

Second lens, on rulerFigure 9: Second lens, on ruler

I can’t believe that it has been 6 years this October since my microscope was first completed with its first lens. I take it traveling on trips, I take it to schools where I work with teachers. I took it to one classroom that was studying lenses and optics for a special unit and one of the students became very interested in making a lens and eventually a microscope of her own! We shifted the lens making set-up to one powered by a motor extracted from a box fan, and a brass and wood design that was more rectangular so it could be made mostly with hand-tools in my office at the American Museum of Natural History. She persisted and it took about two years to finish her microscope as well. Three other students have joined in over the years, one more finished and two are on pause during COVID.

Bancks microscope in greenhouse at Down HouseFigure 10: Bancks microscope in greenhouse at Down House

My Monoculus has a traveling companion once in a while. I ran across a Bancks microscope which I was able to purchase and it was part of the inspiration for my microscope making journey. The above photo was taken at Down House where another Bancks microscope lives. These little magnifying tools have so much to offer in their design. So easy to use, no batteries required, useful for flowers as illustrated with the Bancks above, or rotifers and cyanobacteria on Leeuwenhoek Day in Morningside Park, Manhattan this past 7, September 2020 (Figures 1 and 11).

Monoculus in Morningside Park on Leeuwenhoek DayFigure 11: Monoculus in Morningside Park on Leeuwenhoek Day

This was a short rambling story, if anyone has questions you can send me an e-mail using this form:

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Some of the websites which inspired techniques I used or modified in my microscope making:

de Azevedo, Alvaro Amaro, The Challenge of Grinding Lenses for Single Lens Microscopes, Micscape Magazine, January 2006 (Brazil)

Loncke, Hans, Making a Van Leeuwenhoek Microscope Lens, Micscape Magazine, April 2007 (Netherlands)

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