Stylus Microscope of extremely high quality

[Chuck]

This relates directly to the thread
about the new Bruce DD diamond.

I am ready to spend whatever money it takes
to purchase a very decent tabletop microscope
for examining styli.

I would like to hear from others who have
various kinds, to find out what brands and types are the best.

Someone recently said that 100 power is
all you need. Is that for certain? How
about 200 power? 400 power?

It would seem to me that the higher the
magnification, the more can be seen.

I would like for people who have these to
check in here in this thread and tell about
how their microscope works. Is the depth
of field an issue? Is it an issue getting the
lense up very very close to the object being viewed? How about light? I know that some of
the best ones have their own very bright
light.

Thanks in advance.

Chuck

[ChuckA]

I have two that I use, the main one is a GIA Gemolite with Bausch & Lomb stereo optics head. Has variable magnification from 10.5x to 45x, built in lights above and below the deck, and holders for small items that make it easy to move the object being inspected. I purchased it at a jewelers closing auction for $160 a few years ago, I see later models selling for between $200 and $1600.

As far as magnification the 45x works very well, I can see flat spots on a sapphire stylus easily also worn tips on a diamond stylus. I sometimes wish it had a little more magnification, 70x would be nice. When you get to very high magnifications you start to get to the " can't see the forest for the trees" scenario, also the field of view narrows and the amount of light needed to see clearly gets greater. At 200X or more I doubt very much it will be of any use, unless you are looking at something in the micron range.

The other unit is a Bausch & Lomb unit with fixed magnification of 7X, very large field of view, no built in lighting, works well for a cursory inspection.

Chuck

[Chuck]

Thanks ChuckA for the response.

I have on two occasions, taken my objects
to be viewed (sapphire shaver knives,
recorder cutters, Edison 2m and 4m sapphires)
over to my friendly local jeweler's for
a peek at them using their diamond-grading
scope.

2 separate shops. 2 different kinds of
microscopes. Both with diasppointingly low
power. One is 60x, and I think the other
was maybe 50x.

Not Nearly enough detail for me.

I still contend that back in the early
1980s when I took my stuff in to the inspection dept. where I worked and used
their 400x stereo scope, that is the detail
I am after. At that level of magnification,
every detail is clearly seen.

What I really need to do is to find a big store that sells these scopes (maybe
somewhere in Chicago), and take my stuff in
and try all different kinds of scopes to see
which kind does what I need for it to do.

I would say, offhand, that 100x magnification
is the bare minimum I would want, 200x would
be more like it, and 400x would be what I
really want.

As I recall, the good inspection scope had selectable magnifications of 100x, 200x, 400x.

It's been a very long time since I used that
scope, but that's how I remember it.

Does this jog anyone's memory?

Any ideas where I might go to try all these
different kinds of scopes so I can see
firsthand what I want?

Thanks again. Chuck

[VintageTechnologies]

Chuck, I am the one who suggested that a 100x stereo microscope is all that you should need to examine a DD stylus. One afternoon I and Ron Haring sorted through several dozen new and used DD stylii using an old American Optical scope at 90x (6-power objective lens X 15-power eyepieces). We had no trouble distinguishing perfect NOS from used or flawed stylii and both of us agreed that 90X was adequate. Ron was favorably impressed with my scope and asked my help to find him one - which I did.

I think going beyond 100x yields diminishing returns - although the images are larger, they also become fuzzier, dimmer and have less depth of field. 200x magnification (10-power objective X 20-power eyepieces) really is a practical limit for stereomicroscopy, as far as I am concerned. Anything beyond that would require something costing thousands of dollars.

I own a dozen medical dissecting stereo microscopes, including American Optical (Spencer), Bausch & Lomb, Reichert, Beck Kassel, and Leitz. None of those are the newer zoom or CMO variety, but the classic Greenough design. Several of mine are capable of 200+ magnifications, but most stereo microscopes are typically used at lower powers.

See: http://www.history-of-the-microscope.or ... scopes.php

A microscope repairman once told me the non-zoom Greenough designs have sharper optics, but I think the most advanced zoom models today would likely match them. It's a matter of cost.

I think an AO Spenser would be the most affordable and practical scope to look for. Any scope should have enough clearance to examine small reproducers such as an Edison "C" without removing the stylus bar. DD reproducers are another matter - you have to remove the diamond to be able to examine it from various angles. However, some stereo microscopes were mounted on booms that permit examing large objects laid on a table.

Sadly, there is no place that I know of where a variety of stereo microscopes could be compared at one time. All of mine have come from different sources, sometimes sight-unseen.

[rizbone]

Well, there is this one available on craigslist in northern Maryland.

http://baltimore.craigslist.org/tls/4595468779.html

[chunnybh]

I use a small USB digital microscope with a x250 magnification and built in led lights. It's great for checking styli as you can move it around, video or take pictures It cost me $28.

[Chuck]

Just took all of my DD stuff over to Clinton, Illinois and stopped
in at Watkins Jewelers on the old town square.

They have an old and very robust 60 power diamond grading microscope.
I was allowed to use this microscope to look at all of my DD stuff.

The built-in lamp is not very bright, but I found that by holding a white
card below the object to be viewed, that at 60X, there's just about enough
magnification to see some detail.

It leaves a LOT to be desired, but at least by using that I was able to
see much better than with my little 50X hand-held, LED-lit plastic-lensed
pocket microscope.

Plus, the jeweler's scope has lots of room, and you can hold a whole
DD reproducer under there and see the stylus fairly clearly.

At least I got a peek at them.

Chuck

[VintageTechnologies]

Chuck, I found a small LED flashlight that does a great job of illuminating specimens under a microscope. It runs for hours on a single AA battery. A single focussed LED delivers a much more brilliant beam of light than the old fashioned collimated microscope lights. I hold the light as close as I can to the specimen and try different angles to obtain the best illumination. The light also comes in handy clipped to a baseball cap for doing odd jobs hands-free.

http://www.amazon.com/Energizer-LED-Cap ... d+headlamp

[VintageTechnologies]

Here are some pictures demonstrating an old American Optical stereo microscope that I use to examine Edison phonograph styli without removing them from the reproducer. By adjusting the stereo head on a swinging arm, I am able to view reproducers either on or off the microscope stage. I use an Energizer LED flashlight for illumination. This setup magnifies up to 90x, using a 6x objective and 15x eyepieces. These pictures were taken with an Apple iPhone 4s.