A microtome is a device for slicing very thin cross-sections of stuff, in order to view them under a microscope. Commercial ones are available, but they cost upwards of $50. There is a classic DIY solution, but it involves a piece of old technology — a wooden spool for thread. Outside of antique stores, those aren’t common. Plastic ones tend to be hollow, meaning there’s no guide surface for the razor blade; and the razor is likely to shave the plastic instead of slide across it. Gluing a washer to the plastic spool would address both of those problems. But there is very little gluing surface on the end of a hollow plastic spool.
Lacking a wooden spool, I cut a cube off the end of some scrap 2×2 and bored a slightly-oversize hole through it. Using Gorilla Glue, I attached a flanged nut and a flat washer to opposite ends of the hole. Before the glue set, I used the bolt to center and clamp them over the hole. Gorilla Glue expands 30% as it sets. To avoid permanently gluing the bolt into the body, I carefully removed it after a few minutes. You can see glue in the threads adjacent to the bolt, in the image at right. A few minutes with a wire brush cleaned the bolt threads.
Lastly, I flattened and polished the washer on a lapping plate. The edge of the washer-hole was rough, and glue had expanded out of the hole and onto the surface.
The nut & bolt are 1/4 x 20. One complete turn is 1/20″. So a quarter-turn should be 0.0125″ thin. That, and a fresh razor blade, should make slices thin-enough for a microscope.
This is very interesting… what sort of material would you push through the hold and slice? What is the green stuff in the first photo?
Thanks! The green stuff in the photo is Kale. I needed a demo subject and my wife was making lunch. In general, I imagine anything that can be sliced by a razor could be cross-sectioned. Some stuff will require side-lighting, even sliced thin. If the item’s too small to fit, it can be packed in wax to fill the void around it. Or sandwiched between carrot slices. The first things I plan to look at are carrot, lunch meat, and fruit.
Have you used the microscope video camera devices we have at the space?
Didn’t know there were any. I’ll look around for them. Is there a spectroscope?
I have one of these. I replaced the bulb with an LED. At some point I’ll build a camera mount for it. I mostly use the ‘scope to show things to my niece. I built the microtome mostly because I realized pond water was getting boring and I had no way to prepare non-liquids.
That takes me back to my childhood. Thanks.
Cool! You have first dibs on thin sectioning my brain as soon as I’m done using it.
Just let me know, when! I’ll send Igor immediately . . . :~)