Re: Need advice regarding Watson metallurgical microscope

On Jan 26, 11:30 pm, Christopher Tidy <cdt22NOS...@xxxxxxxxxxxxxx>
wrote:
Hi folks,

I've been looking for an incident light microscope for a while. Recently
I've seen a Watson "Standard Metallurgical" microscope for sale. It's
cheap, but it needs some components: it's missing the power supply for
the illuminator and also doesn't have a turret; it just has a single
objective lens.

I've always been impressed by the build quality of Watson microscopes.
Consequently, I've collected a few incomplete ones which are now waiting
for a project. I have three Watson "Service" microscopes, which are all
missing parts of the condenser assembly, but are otherwise in good
condition and have a selection of objectives lenses and eyepieces.
Sometimes I've seen lenses specially designed for reflected light, but
I'm not sure if these are a necessity. So my first question is, can I
take an objective lens from a Watson transmitted light microscope and
expect it to function well on a Watson incident light microscope?

I'm also thinking of fitting a turret from one of the Watson "Service"
microscopes onto the "Standard Metallurgical" microscope. These two
models appear to share many components. I have a general question about
turrets, though. It's my understanding that you should be able to focus
with one objective, then rotate the turret to change the objective, and
find that the image is still in focus. But it doesn't work on any of the
Watson "Service" microscopes which I have. It isn't even especially
close. Is my understanding wrong, or is there some way in which the
turrets might be incorrectly adjusted? Also, is there any reason why I
shouldn't fit one of the turrets onto the metallurgical microscope?

Lastly, if I fit the metallurgical microscope with a turret, will I need
to fit a different length of drawtube to compensate? What is the effect
of using a drawtube of the wrong length? Will it just change the
magnification (and possibly focusing distance) slightly, or will it have
a more serious effect? From a quick experiment, the former seems to be
the case, but it would be good to have an opinion on this issue as I
don't believe the Watson "Service" sliding drawtubes will fit the
"Standard Metallurgical" because they will hit the internal mirror.

Thoughts and suggestions would be much appreciated.

I've also posted this question in the Yahoo! "Microscope" group.

Many thanks,

Chris Tidy

A power supply can be found else were, either on e-bay, your local
dealer or from Ludl, you don't need a Watson. Now, the reason that
metallographs were wade with single objective mounts is to maintain a
very good control on parcentricity. Later on, in the late '70's,
makers could manufacture very parcentric nosepieces. I wouldn't
change this.

What ever you do, don't think you can get high quality results from
conventionally mounted metal specimens with a biological, cover glass
corrected objective. Metal specimens conventionally have no cover
glass and that makes a whole bunch of difference. The higher the NA
the more important it is to have the correct cover glass or lack of
cover glass. It is conventional in metallurgy to not use oil so NA
stops at 0.95 usually. Some makers during the 160mm days used a
longer correction length for metallurgical objectives. Nikon, for
instance, used 210 mm since metallurgical beam paths were longer since
you had a reflected illuminator.

Since I'm in America I doubt I'd buy a Watson unless I wanted to
collect. As a user 'scope here they are incredibly rare. If your in
England, there a bit easier to find but there still not my first
choice for a metallograph. When you need objectives, etc. they can
be a bit difficult to get.

Thanks,

Kevin Cunningham
SMS

.

Relevant Pages

  • Re: Need advice regarding Watson metallurgical microscope
    ... metallographs were wade with single objective mounts is to maintain a ... Also, with higher magnification lenses I doubt there would be enough room between the focused lens and specimen without raising the lens and losing your focusing, but I guess this wouldn't be a problem if you're only worried about parcentricity. ... Actually the parcentricity on the Watson microscopes I have seems pretty good. ... The x4 and x10 objectives are made by Watson. ...
    (sci.techniques.microscopy)
  • Need advice regarding Watson metallurgical microscope
    ... Recently I've seen a Watson "Standard Metallurgical" microscope for sale. ... but it needs some components: it's missing the power supply for the illuminator and also doesn't have a turret; it just has a single objective lens. ... can I take an objective lens from a Watson transmitted light microscope and expect it to function well on a Watson incident light microscope? ...
    (sci.techniques.microscopy)
  • Any microscope experts here?
    ... But I've wanted a reflected light microscope for a while. ... I've seen a Watson "Standard Metallurgical" reflected light microscope for sale pretty cheap. ... As far as I know, the lenses I've got and the microscope I've seen for sale both use lenses designed for a fixed tube length, not infinity-corrected lenses. ...
    (rec.crafts.metalworking)
  • Re: Anyone know where to buy semi-silvered glass?
    ... In the end I tracked down another Watson "Standard Metallurgical" microscope on eBay. ... With spare parts from the first I should now be able to build a microscope in good working order. ... For the benefit of anyone who comes across this thread in the future, the reflector in the Watson "Standard Metallurgical" is plain glass, not a semi-silvered mirror. ...
    (sci.techniques.microscopy)
  • Re: Anyone know where to buy semi-silvered glass?
    ... In the end I tracked down another Watson "Standard Metallurgical" microscope on eBay. ... With spare parts from the first I should now be able to build a microscope in good working order. ... For the benefit of anyone who comes across this thread in the future, the reflector in the Watson "Standard Metallurgical" is plain glass, not a semi-silvered mirror. ...
    (rec.crafts.metalworking)