GermanHarpist
1623 posts
Jul 08, 2010
3:28 AM
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I thought of buying a usb microscope. There are a couple of good deals on ebay.
http://cgi.ebay.de/Digital-USB-Mikroskop-10-400-fach-VIDEO-PC-KAMERA-NEU-/260621866651?cmd=ViewItem&pt=DE_Computer_Elektronik_Foto_Camcorder_Optik&hash=item3cae46169b
This one for instance gives you 400x magnification with a 2Mpx camera.
A friend of mine gave me the inferior model (200x with a 1.3Mpx camera) to test... here are the results:
Click on the thumbnails to enlarge
 
I was positively surprised by the magnification, but it's still not quite enough. i.e. I would like to see a little more.
Did any of you gather some experiences with usb microscopes and with analysing reeds that way? Some thoughts?
Last Edited by on Jul 08, 2010 7:26 PM
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GermanHarpist
1625 posts
Jul 08, 2010
3:43 AM
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Btw, the first pic shows some embossing and the second and third a pretty bad tuning mark that went a little over the edge.
It's all from a Sp20 in C.
Last Edited by on Jul 08, 2010 3:55 AM
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Andrew
1063 posts
Jul 08, 2010
4:51 AM
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GH, you say 'inferior', but that's only because it has less magnification. They seem a bit cheap to me, and you may find that even though the 'superior' model has twice the magnification, it may, because it is cheap, lack resolution, and thus not actually be superior at all. I am quite impressed by the 200x one, though, although there is some fuzziness in the bottom picture. You need to try to infer how much fuzziness there will be in the bigger model and decide if it negates the extra magnification. And if you are serious enough to go in for a microscope, you should think about how much you want to spend and perhaps go for a slightly more expensive model? I don't know. I'm just trying to be helpful.
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Andrew,
gentleman of leisure,
noodler extraordinaire.
Last Edited by on Jul 08, 2010 4:54 AM
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boris_plotnikov
141 posts
Jul 08, 2010
8:26 AM
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I'm biologist by my first education I always use non-digital stereo dissection scope to look if reed is ok or damaged.
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walterharp
402 posts
Jul 08, 2010
10:49 AM
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biologist is my first and main job, and a decent stereo dissection scope usually has a nice transmitted light through a diffuse source below, fantastic for really checking out those tolerances after embossing
Last Edited by on Jul 08, 2010 10:50 AM
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GermanHarpist
1626 posts
Jul 08, 2010
11:44 AM
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@tooka, yup it's 8 LED's and they do their job. What do mean with 'certain applications'? Are there some cases where they're not good?
@Andrew, thanks a lot. I guess that it should be of better resolution as it has a better camera. However, already with this 'inferior' model I had the problem of focussing (as can be seen on the last picture). While trying to manually focus the microscope moved. When I let go, it was out of focus again. So you really need a better stand construction to get a nice focus.
I checked out the other models. The better ones reflect their quality in price. Thus a magnification around 1000x costs you around 300€. Which is too much.
Then I've just been shown the following 'kid' microscope with a respectable 200x magnification (same as above) however with a stable construction for a laughable 30€.
Aldi-Offer
I seem to see these cheapo usb microscopes all over the place now a days so I guess the price will go down even further.
There are some advantages of having a movable microscope though. You can easily mount it on stuff and focus it on whatever you want. With the 'real' microscope I somehow need to fix my sample/object on the stand...
@walterharp: thanks, 3D sounds tempting however, the magnification is too little. Otherwise,... jummy :) The thing with the diffuse lite sounds like a pretty cool idea. I'll have to check that one out.
@boris, I'm curios to see how a damaged, i.e. fatigued reed looks like. Unfortunately, I don't have the microscope here anymore.
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walterharp
403 posts
Jul 08, 2010
12:56 PM
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I think your magnifications might be a bit off...
the pictures that are on my screen are probably no more than 100 X. A harmonica reed is about 1.5 mm across.
the highest mag image of half of a reed is about 35 mm across on my screen.
That makes the image roughly 46X, i guess you can get he image bigger by about 3 times without degrading quality.
of course you might have higher quality images that were taken originally
You can actually work under a stereo scope, but at higher magnification there is no real way to control things unless you have a micromanipulator.
take for example the image of the hard reed gouge.. you could see that and file it off under a dissecting scope, with a steady hand...
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JohnnieHarp
2 posts
Jul 08, 2010
5:05 PM
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Anybody tried embossing WHILE looking through a dissecting microscope?
What magnification power is most useful?
Last Edited by on Jul 08, 2010 5:15 PM
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walterharp
404 posts
Jul 08, 2010
6:46 PM
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that is what i thought the point of the original post was, but i think he wants to use it for looking for flaws, but there is no reason why that would not work very well, with the correct lighting you should be able to get it very tight and even that way. a good bit of practice too, i have made quite a few microelectrodes under a dissecting scope and it really is an art to work that small
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nacoran
2377 posts
Jul 08, 2010
7:16 PM
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Walterharp, is the magnification off because of the actual magnification or the size of the images on the post?
Ok, thinking on this tiny scale has me thinking. I've tried embossing a couple times. It seems to be about smooshing the reed plate a little to extend out into the reed gap. It seems like sort of a brute force method, applied unevenly to one side of the plate. There are other options. I've seen ways to create a gasket and someone had a harp that had gone through a flood and seemed to play better because of the build up of gunk around the reeds. I've even heard people suggest plating the reeds and reed plate to tighten the gap. Is there maybe a fine tool that could reach down into a reed slot and pinch the edge of the reed slot, like a very tiny vice, or maybe a pair of 'smooth' gears that could clamp down and pinch the edge, kind of like a can opener (only just tight enough to pinch, not cut?)
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GermanHarpist
1627 posts
Jul 09, 2010
5:09 AM
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Walterharp, did you click on the image (to go to the original sized image)? On my screen the half reed is a little more than 10cm, which is about the 200x magnification.
JonnieHarp: actually it was intended for both. For analysing the reeds, the flaws, the tolerances... etc.
I actually plan to build a Rick Epping style embossing table. Which is basically a box which has a backlit cutout for the reedplate. The microscope would be mounted on top, so that I have good control through my laptop.
nacoran, that sounds very cool. What about this idea:
Just put it on a hard surface and pound it with a hammer. :)
The other thing is already done by a couple of customizers. They just go over the reed, pushing it down and widening it a little. This helps to reduce the brightness that come from embossing too.
I like the idea of squeezing the reedplate.
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GermanHarpist
1628 posts
Jul 09, 2010
5:17 AM
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Ok, here comes another idea. I heard that, I think, Richard sleigh cuts the reed plate just off the side of the reed slot with an Xacto knife and thus pushes some of the brass into the slot.
I tried that without success. What about using some sharpish object and... hammering :) it on the same spot, thus pushing some of the material inwards?
Last Edited by on Jul 09, 2010 5:17 AM
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