FMF - Friends of Minerals Forum, discussion and message board

[Paul S]

I have come up with a cheap solution to a common problem. While looking at minerals through a microscope, it happens a lot that a specimen needs to be viewed under a different angle to get a better focus or to get a better view of a certain part of the specimen. One could use sand or forms of fixation kit or rice to position the specimen at a different angle, while preventing it from falling over. I tried those methods, but I was not satisfied with them. They are not accurate enough and one needs to touch the specimen a lot to get the tilt right.

So I came up with the following tool: a ball table. They can be bought, mostly designed for specific microscopes, but they are very expensive. So I build one myself from various parts I had lying around. As you can see in the photos, I used a piece of wood with a hole in it, I glued another one underneath it, so the plastic ball could sit in the hole. There was however not enough friction between the wood and the plastic, so I added a rubber band to make sure the plastic ball would not move after being tilted. In the plastic ball, I added a bit of sand as extra counterweight and I glued a round piece of wood in the plastic ball for the specimen to sit on. I then added some grey 'blue tack' (it’s a kneadable form of rubber eraser) so specimens won't slide along the surface.

I also made a clear version for through lighting, it consists of the same plastic ball, but this time I glued a petri dish into it. It sits a bit higher into the ball, but only smaller specimens will require through lighting, so it’s not really a problem.

Of course the whole setup works only for smaller specimens, but everything that will fit underneath my microscope will fit on the ball table.

I hope this bit of kit will inspire you all, for I have found it very useful and easy to operate.

[Pete Richards]

Here's my version. A hemispherical steel bowl (actually was the bowl from a gravy ladle), a plastic jar cap with the top cut out, and a few ceramic magnets glued to plexiglass. The steel bowl is partly filled with plaster of Paris, painted black. The steel bowl does not quite touch the magnets, but the attraction creates enough friction to keep the bowl oriented as desired.

It works great and is very useful and efficient for orienting specimens for viewing or photography under the microscope.

[Paul S]

That is a very nice system you came up with Pete, I guess that even specimens which are top-heavy can be tilted under a large angle.

I did wonder, are metallic and magnetic minerals a problem due to the large magnets that hold the bowl?

[Pete Richards]

[Scott LaBorde]

I have taken Pete Richards design and slightly modified it. I created a video to show how it works and how simple it is to make.

** In the video I incorrectly label the steel ball a "ball bearing" when it's just a steel ball (apparently a common misnomer - oops).

https://www.youtube.com/watch?v=TsQhWhJr7VE

https://www.rockhoundlounge.com/cgi-bin/yabb252/YaBB.pl?num=1408625653
(links normalized by FMF)

[Pierre Joubert]

[Scott LaBorde]