Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Your home microscope - like/dislike
#1
Adonstar USB microscope
https://www.ebay.com.au/itm/Andonstar-50...SweZJaRet2
I wouldn't recommend the Adonstar, I struggle with it, the stand is wobbly.

Because of that I bought another one, twice as expensive, still not happy with the resolution
https://www.ebay.com.au/itm/3-5-LCD-500X...SwcUBYSQ4A

Yet have to find a satisfactory one without getting broke. I remember liking Jan's BRESSER microscope that he got as a present from his children I believe.
https://www.bresser.de/en/Microscopes-Ma...m-3-5.html
Jan, are you happy with yours?
http://knifeGrinders.com.au
Reply
#2
More than year ago, as my own Christmas present, I have bought a School LCD Microscope with 3.5" display and 5 MP CMOS sensor manufactured by Bresser GmbH. (Germany). http://www.bresser.de/en/Microscopes-Mag...m-3-5.html
Comfortable is that it includes a mechanical desk with vernier. http://www.bresser.de/en/Microscopes-Mag...-Desk.html

It is solidly designed instrument with fully sufficient optical magnifications 50X, 125X and 500X. It works perfectly for thin biological samples which are illuminated from below and are viewed in transient light. See below an image of Tormek honing compound with 3μm grains. The image was taken in transient light at mag. 500X.

   

It does not work perfectly for bulky samples, like blades, illuminated from the top which are viewed in reflected light. In this case for large magnification the lens has to be very close to the blade and the field of view is very narrow and also the field of depth may be insufficient.
   

The LED illumination from the top is for our purposes also not ideal. Metallurgical microscopes use halogen lamps.
LED light is coherent and as such may be more prone to colour interferometric effects which then obscure the observation. My understanding is that the semi-regular grooves and scratches on the edge serve as a diffraction gratings causing the rainbow effect.

For standard edge inspection the magnification 125X is more than sufficient. Below you can see scratches on the edge of a new Morakniv.
   

In the last image you can very see small chips in a blade made of WG-10 steel, which tends to be chippy. Magnification was 500X. It was difficult to use the maximum magnification because the objective overshadowed the object illuminated from above.
   

It is good to have a scale attached to the image. Sometimes the SW offers it, but in my case it was quite challenging DIY task. I am ready to share the know-how for it.

Jan


Reply
#3
Mr. KG, Thanks for starting a new thread!

Generally, and with variations within each, there are four main types of optical microscopes.  Biological, dissecting, metallurgical and USB.  But what do we need for blade edge microscopy?  I’ll note some pros/cons for each type in consideration of blade edge microscopy.
 
Biological microscopes:
 
This is the type of microscope most folks think of when they think of a microscope.  This type is NOT good for blade imaging. 

   
 
Pros: 
Good price/performance ration.
Very high magnification.
Stable frames and accurate focusing.
X/Y stage available.
 
Cons:
Biological scopes are designed for glass slide mounted specimen observation with the light source below the microscope stage.  Light passes through the mounted specimen to the lens.  Viewing a blade only produces a black silhouette of the edge.  It does not work, and is not designed for using other than transmitted light through the specimen.
 
Extremely short working distance.  The working distance is the space between the objective (lens) and the stage, in other words, where you would slide the blade under the lens.  This can be as short as a few millimeters (+/-) in biological scopes.  Lenses are available to increase working distance, but they are very expensive and the scope is not designed for incident illumination (light reflected off the surface of the subject).
 
High power = short Depth of Field/Focus (DOF).  High power biological scopes have extremely shallow DOF.  Depending on the magnification and aperture size this can be measured in um.

Dissecting microscopes:
 
Dissecting microscopes are good for looking at blades.  They are designed for viewing the surface of 3D objects using incident lighting.  Great for dissecting and general inspection of parts including live view on a computer screen.
 
Pros:
Extremely large working distance.  We’re talking 100 mm or more.  You can put your hand under the lens.
Sturdy frames and accurate focusing.
Very long DOF.
Large field of view.
Usually zoomable over a large magnification range.
Many have stereo eyepieces.
Halogen lighting.
Good for attaching a camera to.
 
Cons:
Low magnification.  Generally 50X or less, some 80X with 4X eyepiece.  Still very useful, but in many instances will leave you wanting for more magnification.
 
Metallurgical microscopes:
 
If you have $1,200.00+ US to spend on a microscope, this is probably what you want.  They are professional instruments with high quality optics, designed or looking at metallic surfaces.  Many different versions available.  Top/bottom viewing, lighting options including through lens, good choice of high quality glass.  Available in bright-field and dark-field versions.  I won’t go into the difference here, but dark-field is probably ideal. as it scatters the light source to reduce reflection and increase contrast.
 
Pros:
High magnification.  800X not uncommon.
High quality optics.
Incident halogen lighting.
Large working distances.
Good DOF.
Sturdy stands and accurate focusing
X/Y stage available.
Great for camera work.  Excellent image quality.
Available in brightfield/darkfield versions, some with darkfield adapters so you can have both.  These usually are more expensive. 
 
Cons:
Prices range from expensive to a whole lot more expensive.
 
USB microscopes:
 
This is what we all end up with because they range in price from almost free to only a couple of hundred dollars.  They include software for image viewing/saving on a computer.  The major downsides are that they are very difficult or next to impossible to get high quality imagery from, and they are difficult to use.
 
That said, they are actually useful, and I have posted many examples of USB microscope images here on the Exchange.  Sadly, it’s what I use.  I’d be lost without it.  I consider a microscope, even a USB microscope, and an edge sharpness tester absolutely essential.  Anyone interesting in edges needs both.
 
Pros:
Extremely inexpensive. 
Very long working distances.  3 mm – infinity.
Portable.
Computer ready.
Great fun for ages 4 and up.
 
Cons:
Feeble, crappy, junk for frames if they have one at all.  Most are worthless.
Very fussy focusing.  Can be a frustrating hair pulling freak show to focus.
Crap for optics.  Junky glass/plastic lenses, low resolution, fuzzy images.
Poor light transmission due to low quality glass or plastic lenses.
Cheapo crap for lenses causes lots of bizarre artifacts and reflections in the images.
Top LED lighting surrounding the lens.  Produces lots of reflection and rainbow effects off steel.
Top LED lighting is probably the worst kind of lighting for reflective surfaces.
Optical magnification limited to about 200X.  Much above that and focusing and DOF become a nightmare.
Requires you to build a frame to make focusing slightly less of a nightmare.
Many have a nightmare rotating knob on the barrel for focusing.  Impossible to focus without moving the scope.
Reply
#4
I have tried to use a Veho 400, with basically 0% satisfaction. I bought it to be able to observe and take pictures of edges. I don't remember how much it cost, but it's next to worthless. 

Many years ago I started buying all kinds of magnifiers. They weren't expensive, from $5-$25. I probably have about 20 different kinds, from 10x -100x. Some have LED lights, some are variable power. Mr Rupert recently gave me a nice one with good lighting and metric/fractional scales that I like quite a bit.

The best regular "jewelers loupe" I've found are  Belomo's 10x and 20x. They're about $25 and $35, respectively. They are very high quality, with nice, protective carrying lanyards. They seem geared toward professional rock and fossil hunters. With higher quality lenses, there's no need for lights with batteries. If I need LED lights, the chances of me leaving the light on, and running the battery down, are pretty high.

About 6 or 8 years ago, we found the 35x "mini-microscope" on Amazon for about $5 or so. They worked pretty well, but needed the LED light. A year or two ago, the 35x was replaced with a very similar 60x, which are available on Amazon right now for $3- $10, depending on where you get them.  

These mini-microscopes are as close to perfect as anything I've come across. The lenses are large enough that they don't need the on-board LED. They are incredibly easy to use- as easy as a normal 10x loupe without a light, and 60x is enough to see Everything. 

I'm not exaggerating at all when I say these are a game changer to me. I literally use one every time I sharpen a knife. They allow me to Closely inspect both sides of a 4" blade in seconds. Nothing...Nothing I've ever seen comes close- in magnification or ease of use. 

Type in "60x mini-microscope" on Amazon to find one. Like I said, you will find them available from multiple sources. I've ordered 3 times from different places and gotten identical products, in identical packaging.
Reply
#5
I start to use microscope and loupe during the sixties. I have stereo microscope and USB and some pocket models - and a lot of loupes. Today I only use loupes. Sometimes I use my stereo microscope in X 10 or 20. I seldome use the USB microscope today.

When I create my sharpening tools I evaluate a lot of things about sharpeners and grinding results and I sharpened ten thousends of edges with my mkcroscopes - but I found that for normal use of a knife loupes works fine - and best.

I am a traditional knife user. That means that I work mostly in fresh wet wood, skin, fresh meat, fish and other natural materials. I evaluate my edges from that type of use.
Reply
#6
I am seeking ideas for fixtures to hold knife blades and other sharpened items for examining the bevels, edges, burrs, etc., under., under magnification. 

I have a dissecting microscope with a native magnification of 3.5-45X and a 2X multiplier to get up to 90X.  I realize this isn't optimal, but it is a compromise for using it with my granddaughter to examine bugs and other micro stuff.  Last weekend we were looking at earthworms she had dug up.  A while back, while looking at a Yellowjacket wasp exoskeleton, I discovered it had a mite. 

I have and adjustable angle plate (somewhere, can't find it at the moment) that seems like it could be a good beginning.  I want to be able to hold blades such that the bevel is level and possibly slightly inclined to get views of the edges, etc.  I'm not sure yet how I would actually secure the blades to that angle plate.  I made it, so am not adverse to putting holes in it for mounting things. 
   

I am wondering what some of you use. 

This microscope is binocular for viewing and has a trinocular port for a camera.  The camera I have is 18MP.  I have been having limited success getting very good quality still images.  I got this camera for its video speed, as much for its MP, so live things could be viewed on the computer at something close to real-time.  For that it works pretty good. 

The trinocular is not parafocal with the binocs.  I made a focusing attachment for bringing the camera image into focus when the binocs were, but then I realized that if the image is not in focus in the trinoc port, no adjusting of the camera focal length is going to improve the camera image.  So, I use the microsope's focus function to focus the camera image.
   

So, here again, I am wondering what some of you use. 

Thanks,

Rick
Reply
#7
If you can learn how to use one of THESE you can inspect both sides of a 4" blade in unbelievable resolution in 10 seconds. No batteries required, but I use the battery compartment for a handle.
Reply
#8
(04-18-2018, 12:37 PM)Mark Reich Wrote: If you can learn how to use one of THESE you can inspect both sides of a 4" blade in unbelievable resolution in 10 seconds. No batteries required, but I use the battery compartment for a handle.

Mark,

Looks like a very handy device to have around the shop.  Many times the OptiVisor is just not enough, even with 2X or 3X reading glasses.  I ordered one. 

I still have the microscope, however, and still want to view and photograph blades/edges, so I am still interested in what some of you use to hold them for this purpose.

Rick
Reply
#9
Don't know Rick. We've been round the pole on several occasions with Grepper on the microscope question. Seems like it always comes down to $100.00 or $1200.00 and its not really clear what $1200.00 is going to buy you from an optical standpoint because most of the metallurgical scopes are much lower magnification. We're a $100.00 bucks here but did invest in the construction of a solid mounting apparatus and stage for the scope. Would like to be of more help but we haven't even been able to answer our own questions on this subject.  Mark R. is part eagle and can tell the sex of a gnat at 100 yards (and he's still just a pup) so he doesn't need much help.
Reply
#10
Mike,

I think you are answering a question I did not ask.  I already have the microscope and camera. 

I am asking about fixtures for use under the microscope to hold blades so the bevel/edge can be oriented for optimal viewing/photographing.  What do you mount the blades onto to hold them in position during viewing and photographing?   

Please see the first photo in my initial question, showing the adjustable angle plate, as an example of something I have that I think could be used for this purpose (if/when I find it).

I am asking to hear about and/or see pictures of the devices you guys use for this purpose.

Thanks,

Rick
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)