Not metal related, but does anyone know of a forum or newsgroup where microscope enthusiasts hang out? I picked up an American Optical Model 42 scope at a flea market today and need to buy one ocular for it. I can look through one ocular and see what's under it so it's useable as it. I plan to use it in the shop to look at small parts and the sharpened faces of small cutting tools, plus whatever else a dissecting scope might be useful for.
Not metal related, but does anyone know of a forum or newsgroup where
I have an English-made binocular scope that I use for exactly that too! Excellent for checking Acme threading tools against gauges, for instance, although I need to make a tiny X-Y-Z stage to go under it!
With luck someone will put you onto a source for the missing ocular, can't help there, but... If you have one ocular, you're half-way there, if it's a simple convex or plano-convex lens (or multiples of - see below) you can measure the focal length of the lens with a very distant light source (the sun, for instance?) by measuring the distance from the lens to its focal plane, that and a few measuements will give you all that you need for ordering a lens (should only be a few local currency units), then the ocular body should be fairly easy to turn up on the lathe? The lens could be held with a threaded ring, or even a circlip in an internal groove.
If it's a more complex eyepiece you may need to dismantle it and do the measurements and then order up a set of lenses to suit, the page at
illustrates the various types - a stereo dissection 'scope will be relatively low-power so is likely to have one of the simpler types.
I'm having difficulty finding an illustration of that particular model -- but is it one of the stereo zoom ones with two eyepieces, and a zoom control marked from 0.7X to 3X? With a pair of *matched* 10X eyepieces, this gives you a very comfortable range for the sort of thing you want to do. The "matched" means that you cannot trust getting a single eyepiece that it will match what you have closely enough.
You want 10X wide field eyepieces for this.
Doing an eBay search for "stereo microscope eyepieces" I find several which look reasonable. Here is an example:
eBay auction # 310262853424
mine measure 23.23mm small end diameter which is pretty close to these.
No idea about the dealer.
Many shorter eyepieces probably are not wide field enough, and are also probably not the right length to focus properly in the stereo zoom microscope.
I would suggest that you measure the smaller end of the eyepiece which you have to check what size you need for your 'scope.
If you go through the search -- you will find rubber caps which fit on the eyepieces and block off side light, as well as spacing your eyes to a comfortable distance -- assuming you do not use glasses. If you do wear glasses for infinity focus, use the bare eyepieces without the caps added.
It is more likely to be of the type shown shortly below the "Microscope eyepieces" header in the above-mentioned Wikipedia entry. (Most of what are shown there are astronomical telescope eyepieces.) And in particular, the design of the AO stereozoom microscopes usually calls for "wide field" eyepieces to give reasonable images through the full range -- and that calls for more complex optical design. (As I posted before, I can't find your model with q quick web search. Mine is an AO model 569 (or some number close to that), it is downstairs in the shop (of course), and I did not write down the model number while I was measuring the eyepiece mounting barrel diameter. :-)
As a result, while you might try making a pair of eyepiece (I would not suggest making a single one, no matter how accurately you measure the lenses and mounting. If you can get the elements needed in pairs, you can at least make matching eyepieces and be more comfortable. With a stereo setup, any mismatch in the two eyepieces will lead to eyestrain. I've already posted a URL for what looks like a good pre-made pair for your purpose.
If you make your own -- turn very fine threads on the ID of all barrels between and beyond the lenses, and then black anodize (if made from aluminum, or get a very flat black paint to apply to minimize internal reflections. But also -- take care to make the two as close to identical as you can manage.
Good advice. I would add that I am fairly certain the AO microscopes used a
23.2 mm diameter eyepiece (note: sometimes there is a number after the the magnification written on the eyepiece. This is NOT the diameter. It is called the field number which is the diameter in mm of a field stop inside the eyepiece. Divide it by the objective magnification to get the field width at the sample.)
If you search Ebay for just "10X eyepiece" you will get more hits. If you do not see an eyepiece that seems to exactly match your make and model, you really should get 2 new matched ones so you do not have slightly different magnifications in each eye. As noted by Don above, you want wide field for a low power stereo microscope. Also, some eyepieces are easier to use with glasses due to the longer eye relief. Sometimes these will have a little glasses symbol on the side. Otherwise you can generally tell since longer eye relief eyepieces have a larger lens in front.
These guys will be able to help you figure out what you need, and will give you a square deal:
I can not reccommend John Simon highly enough. I've bought two microscopes from him - he gave me an unconditional money-back guarantee, and took the first, five years later, at full price as a trade-in on the second. A real class act.
BTW, if you're ever in the area, his antique microscope collection is worth a look.
Some patience on ebay, and you will almost certainly find something that'll work. I've seen oculars going fairly cheap.
Do consider an LED ring light! I just added one, with 64 LED's, and it was more than worth the price paid. FAR better than the single behind the lens light source that B&L intended for my scope. With the great lighting, I find myself using the scope almost every day now.
You can see the model in the catalog located at this URL:
Mine isn't a zoom. I consider it a high school level microscope even though the original list price in the 70s was $500+.
A parts breakdown is available at this site:
After looking at the parts breakdown, I suspect that I need lens assemblies for both oculars. The lenses for this scope are not the usual drop in 10X oculars. There's a stack of lenses in the ocular tube and covered by a black cover that looks much like the exposed part of a regular wide field ocular. Somewhere at work I think I have a pair of 15x oculars that were discarded many years ago. I'll have to bring them home and see if they fit. I could try the oculars from my AO series 10, from my student years, but it's too much work to excavate it from the closet. My suspicion is that these won't work in this scope, but I'll see.