Best microscope for analyzing sharpness?

[Dan Barr]

Hi all,I am looking for advice on which microscope is the best for analyzing sharpness. Intent: observe plane blades and chisels after individual/successive sharpenings on various media. I.e. Oil stones, waterstones, Arkansas, ceramic, strop, etc.I don't think I can afford an electron microscope. Who knows, maybe the prices have come down over the years. Maybe there's an electron microscope app for my iPad...... :DAny advice on an affordable microscope that will allow me to make meaningful observations would be appreciated.Thanks,Dan

[Prashun Patel]

Are you trying to make comparisons, or just trying to observe to make sure you're adequately sharpened?

[bill tindall]

Email Steve Elliot, sgelliott@cablespeed.com, and/ or check out his web site. Steve takes the best pictures I have seen with inexpensive equipment. That said, his images are not close to the detail one can capture with a microscope set up for imaging metal surface(and costing thousands of dollars). You can find images I have posted on WoodCentral taken with a Nikon set up for metal imaging. That said, the best by far imaging will be with a scanning electron microscope. In fact Lee Valley has recently bought such equipment to support their sharpening and metal selection studies.

As far as magnification to just support sharpening, a 10X quality hand lens works fine. Unless you are doing sharpening research the hand lens is all you need, so long as it is a quality lens.

[David Weaver]

A cheap dissection microscope will be fine. if you can find a setup that takes pictures like steve elliot's, even better. His pictures are fantastic, like bill says. I haven't seen anything as good just looking through my own stuff, let alone in pictures. Alex gilmore used to have excellent pictures, too, but he's removed a lot of that type of picture over time, I don't know why.

Just looking at edges will confound you in terms of trying to determine sharpness or usefulness in woodworking.

If you are really looking just for absolute sharpness, anything in the 15k shapton range will begin to leave a polish so consistent that it will be difficult to see the differences between stones for purposes of sharpness, they will all just look a little different. Natural stones or stones that allow swarf to roll around will create a duller looking edge, and deciding how sharp they actually are will be next to impossible unless they are hard enough to hold their particles in place and dig a groove in whatever you're sharpening.

Coarser stones will leave scratches you can see much more easily, and there will be some stones that leave mostly small scratches and a few big ones, that will make a yes-or-no type of comparison difficult to tell.

I think if you are comparing finishing stones, you will almost have to hollow grind or microbevel a chisel edge (polished on both sides of the bevel of course, with the stone in question) at about 20 degrees (any more blunt than that, and the HHT will seem to find an upper limit around 2/3), do a light palm strop of the chisel edge to make sure all semblance of the wire edge is absolutely gone and then do the hanging hair test.

You can do this with a plane iron, too, but you'll have more polish work to do unless you back bevel the iron.

I hate to say it, but when you get around a micron or below, it gets to be almost impossible to tell what's sharper. Technique becomes very important and a battery of hanging hair tests will sort of describe what edge is what.

It's really not particularly practical work for woodworking, but it is instructive and interesting to do, and the HHT will really help you gauge where the quality of your honing is.

http://www.coticule.be/hanging-hair-test.html

All of that said, like Bill says, above and beyond the loupe, this is really getting into space cadet kind of stuff (well, that's not exactly what he said, but I saw the word loupe :)), but a lot of us have fooled around with it out of curiosity. I did it to try to find out how fine my natural stones were, many of which people described as being much finer than any synthetic hone, when in the end out of 10, 8 were different and less sharp, and two are sharper. They are both stones designated as razor stones from mines and would be difficult to use effectively woodworking.

I could not tell that from the microscope, though, only the HHT confirmed that.

[robin wood]

If you are not looking for photos then a good binocular microscope with magnification in the 20x-80x is what you want. Something like this 207479

This is the one I use I picked it up new from ebay for £65 there are good old ones for similar money. This allows you to see critically the difference between the grooves left by a shapton 15,000 and a natural waterstone say. It helped me a lot to asses all my different stones (I have a lot) in a more objective manner, this in turn speeded sharpening. The other thing it does is I use it when sharpening to have a quick glance along the edge and check that I have reached the edge all the way along with each successive grit before progressing to the next. All this can be done with a £10 plastic microscope like this http://i206.photobucket.com/albums/bb176/thewoods_album/L6_001jpg450.jpg search ebay for "microscope loupe" but these are not so easy to use having a short depth of field and reversing the image, most Japanese woodworkers use them though. 30x is best for these.

[Dan Barr]

I would like to do both.Make comparisons and check for sharp.So far there are some really useful replies here. Thanks all for the input.Thanks,Dan

[Dale Sautter]

Dittos what Bill said above about simply using a hand lens to quickly check and move on... but for fun, a couple of my first pics taken using the following... 1,2,3:

Make a USB microscope article:
http://pcformat.techradar.com/article/make-usb-microscope-11-06-10

Logitech 1080p Webcam Pro C910
http://www.amazon.com/Logitech-1080p-Webcam-Pro-C910/dp/B003M2YT96/ref=sr_1_sc_1/187-3855673-6192607?ie=UTF8&s=electronics&qid=1298343150&sr=1-1-spell

Celestron 44102 400x Power Laboratory Biological Microscope
http://www.amazon.com/Celestron-44102-Laboratory-Biological-Microscope/dp/B000Q7964S/ref=sr_1_4?ie=UTF8&qid=1298258228&sr=8-4

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[Randy Klein]

I use this loupe from LV while sharpening. It works great, especially when hold the light so that it rakes perpendicular to your scratches.

http://www.leevalley.com/US/wood/page.aspx?p=51092&cat=1,43456,43351,51092

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[Prashun Patel]

If you ust want to check for sharpness, a cheap jeweler's loupe will allow you to see scratches and nicks even in the 8000gt range.

[Andrae Covington]

I use this loupe from LV while sharpening. It works great, especially when hold the light so that it rakes perpendicular to your scratches.

http://www.leevalley.com/US/wood/page.aspx?p=51092&cat=1,43456,43351,51092

207497

The microscopes are out of my league, I also use the LV loupe and find it handy. It was especially useful when I was first learning to sharpen, wondering "how long do I have to work on this stone to remove the scratches of the previous stone?" At the course grits, that's obvious to the naked eye, but further up it became difficult to see at times. I just read the product description again and noticed they say it can be used to help remove slivers. Since I usually get them in one hand or the other, and I need the unwounded hand to hold the tweezers, I'd need a third hand to hold the loupe.:p:confused:

[Stuart Tierney]

http://i206.photobucket.com/albums/bb176/thewoods_album/L6_001jpg450.jpg

One this like.

Anything more is overkill, anything less might not be sufficient.


207503

This was taken with a 'proper' microscope, that still wasn't set up and had poor glass in it. It's at 400x and no, you don't need to go that far. The higher the magnification, the more troublesome things become but the more detail you get too.

Hope that helps, and I'd try and avoid a 'loupe', they can be useful for coarser sharpening, but a proper combination of lenses will show a lot more detail at a higher magnification and be a lot clearer as well.

Stu.

(Who's got a drawer full of glass and a shelf full of microscope with a K-mount sitting atop the mess...)

[Chris Fournier]

I have played around with this a few times over the years to say the least. Honestly, if you insist on relying on your eyes only you simply don't need any magnification to tell if an edge is sharp or not. The keenest edge reflects no light, in fact it kinda looks black. Right off the grinder and 800 grit stone I can tell if I've got sharp, no loup, no microscope, no guessing.

It is fun to look at cutting edges under magnification but it is really not a useful enterprise if your desire is to actually work wood rather than design his and hers multi-bladed personal razors.

And to cap it all off, your sight is only one sense that you can use to determine the sharpness of an edge. Pull a sharpened edge vertically along your thumbnail and you can tell just how sharp it is. Sure it may take a while to get the feel but I'm telling you that with your eyes closed you can tell sharp from sharpest.

Honestly, don't get bogged down with this microscopic inspection of your cutting tools, it is a waste of time and money to say the least. Employ good sharpening practices and equipment and use your everyday senses to tell you what is truly sharp, this is the path of a woodworker, though perhaps not the path of a writer. And many good writers have written about this subject and I am most certain that you will not move the subject matter forward one fine edge from where they have taken us to this day.

Spend your time and money on processes and tools that work wood - you'll become an expert sharpener with no need for coke bottle glasses.

[Russell Sansom]

A few years ago when I retired and started buying state of the art chisels and plane irons, I decided it was time to get even more serious about sharpening. I started looking for microscopes and landed very quickly on this kind:

Bausch and Lomb StereoZoom 4
An ebay search will show you what they look like.


The ones I know about were used for electronics assembly here in Silicon Valley. They offer two-eyed viewing and the power of the optics can go from 10X to about 65X. It took me a little practice, but I now I can clearly see where an edge stands. I can gauge pretty accurately how much grinding will be required to remove a nick. And I can quickly watch an edge degrade over time.

I have enjoyed this tool tremendously. I got a completely new understanding of my steel. And it's amazing for removing splinters.

[Jamie Buxton]

This guy has a very interesting site about sharpening, using a "toy" computer microscope for imaging. http://www3.telus.net/BrentBeach/

[Jim Koepke]

I have played around with this a few times over the years to say the least. Honestly, if you insist on relying on your eyes only you simply don't need any magnification to tell if an edge is sharp or not. The keenest edge reflects no light, in fact it kinda looks black.

I am with Chris on this. I used to use a hand lens. The parts of an edge that are not fully sharpened will look like little lights along the edge. If a section is not keen, it may look like light hitting a strand of a spider web.

The lens I use now in relation to sharpening is my magnifier lamp. I use it to watch while shaving arm hair to allow less shaving to see it working. After a lot of blade sharpening, there aren't a lot of hairs left to test the blades.

I like the HHT. The levels of sharpness corollate somewhat with shaving arm hair.


I just read the product description again and noticed they say it can be used to help remove slivers. Since I usually get them in one hand or the other, and I need the unwounded hand to hold the tweezers, I'd need a third hand to hold the loupe.

I have a couple of swing out hand lenses. I can curl a finger through the body of the open lens and use a couple of fingers from the same hand to hold the tweezers. A little awkward, but it works.

jtk

[Prashun Patel]

A jeweler's loupe ($6 on Ebay) improved my ability to sharpen. I'm able to see tiny nicks that are otherwise getting harder and harder to see with my naked eye.

[Will Blick]

I am sure glad I am not alone in this endeavor..... makes me feel better....

First, magnification allows the eyes to see what is not possible.... Its remarkable studying the blade profile.... its almost a sub-hobby, within a hobby.
A high powered microscope with excellent optics is best, but very costly....
IMO, to see fine detail on the blade, I have settled on a 100x loupe, easy to use, fast and shows me things that continue to amaze....
For imaging, it must be with a microscope imaging system, as camera lenses can't do 50x magnification, different animal....
I often thought about mounting a pc display in the shop and viewing it under a usb microscope, but fear the laughter from anyone who sees the set-up... hee hee
the display eases the tension of your eyes looking through small magnifiers with tiny exit pupil diameters...

[Stuart Tierney]

Will,

Interesting that...

I bought a 'new' microscope, came from India. The glass was nothing special, and the illuminator was not suitable for here (voltage).

So, in an effort to try and rectify the situation somewhat, I asked that instead of sending out a new power supply for the illuminator, could they do something that would let me take pictures?

They wanted to sell me $200 of USB camera, all 1.3MP of it...

I told them to not bother.

After upgrading all the glass, slipping in a dimmable LED illuminator, tweaking the body to stop reflection and light bleeding, adding a k-mount SLR camera adapter to the top and tethering the DSLR to the computer and some nifty software, lo and behold I got what I wanted and far beyond what the clowns who made the scope told me I could have.

Rather nice to have up to 1500x, proper Kohler illumination and a tethered 10MP DSLR hanging off the top of it all. All that and a cherry on top, heaps of field depth at any magnification I choose to use. :)

(Nifty software. ;) )

And before someone out there tells me I'm nuts/crazy/OCD or have some other malady that may or may not be as a result of my ancestors, the whole mess is actually for work and as such, I have a completely legitimate reason for having something so OTT.

If I didn't need it, there's no way I would have dumped the money on anything even remotely resembling it. The $10 hand-held thing I also have is more than enough.

Stu.

[Will Blick]

OK Stu, you peaked my curiosity... :-) You're not crazy, you're just one of us, welcome :-)

IMO, you have maximized the price/performance ratio. The reason is, the recording sensors of good DSLR are mass produced and therefore quality / price ratio is incredibly favorable vs. low volume microscope imaging.

Since you have been down this road, what scope would you suggest for this, what Canon adapter to use, what tethering software are you using for live view? What magnifications do you find best on the scope? IIRC, live view has a limit on output resolution, are you aware what it is? Hopefully HD, but I think its VGA...

[Stuart Tierney]

Just quickly since it's past my bedtime...

I actually use a Pentax K-x, so it's got that backwards compatible K-mount on it. Pentax also makes a eye tube adapter that I've got (mine's old, but perfect condition, M42 mount) and onto that I've got a M42-K adapter which is what I normally use. I've also got a couple M42 to 49 and 58mm adapters so I can just screw a lens on there as well if the need takes me.

Glass wise, I've got an Olympus 15x camera eyepiece coming soon, otherwise the standard 10x and 15x widefield work well enough. You can also use the camera without an eyepiece, and the images are super clear when I do that, but you drop magnification.

If I were doing it again, I might well go down the same road, but buy a new Chinese model. Their stuff seems to be better finished, because my Indian unit was rough. Illumination glass is ok, but the rest of it is rough. Still works smoothly though. If I was patient, I'd hold out for a used scope of known brand, Olympus or Nikon here would be best. B&L probably more common in the US.

On mine, I had to completely rehash the illuminator, re-finish inside the barrel to cut down reflections, black up a lot of bits and piece for the same and completely replace the objectives. I'm actually using Chinese objectives right now, 4X plan, 10x, 20x, 40x, 60x and 100x semi-plan. I couldn't justify the added cost of a full plan setup, and I don't think I'd go beyond 40x with Chinese glass. The 60x was a look-see, and the 100x came as a set.

As a side note, I had to study up on how to re-adjust the illuminator light path to make it work properly. I got it, but there's not much room for error. The second lens is at the limit of it's adjustment and the aperture is a little too rough for my liking. I'm thinking of pulling an aperture out of an old prime lens with fungused up glass (not repariable. :( ) and adapting it to suit. Makes an enormous difference getting the light 'right', since it cuts down ghosting and flare and really tightens the images up. Just 'light' makes for fuzzy crud, dialed in you really good and crisp images.

For pictures as are commonly seen in the innerweb, I think 10x at the camera with 4x, 10x or 20x objective will give crystal clear images with good depth of field. The 40x is, at the moment, the practical limit of objective, and I'm not 100% happy with the 15x at the eyepiece. Hopefully good glass up there will change things.

For tethering I use a beta gnu license bit of software called pk-tether. It's unpredictable, but usually works well enough. All I aim for is clear images on live-view at the camera and take the picture, and they're clear when stuck into the computer too. The big key here is to either remote control the shutter or time delay it, since any vibration or flex will give poor pictures. I've got both options, but either will do. Using the viewfinder for focusing is pointless. You've also got to have an idea of what the ISO and shutter open time will do for a picture, otherwise you're shooting in the dark. Literally. I prefer to not put ISO above 400, and dial in the shutter time/illumination/illuminator aperture to suit.

I know that having proper tethering software would make life easier, but I use what I got. It works, and once I get some proper time with it, shouldn't be a problem. Once I set up some blade holders and tweak the x-y stage so it's smooth, there's no reason I couldn't also do video as well.

It's late now, and I have an early start, if I have a chance I'll take some proper pictures and get them up.

Oh, last bit of info for now. There's a freeware thing that will take a series of images, pull out the in-focus parts and meld them into an image, giving a full depth of field. I've spent zero time with it, but it should be able to let me take high magnification images and stick them all together to get something approaching what a scanning electron microscope can do. Not the same resolution, and still restricted by being reflected light only, but better than the extremely shallow field depth you get off a single picture. The nice point is that because it's all optical, colour is already there and cranking up the magnification is easier and much, much cheaper.

Very useful gadget, but again, too much money for someone who just wants to see where they're going wrong/right.

Stu.

[Will Blick]

thx Stu...
yes, the process is called focus stacking, I use it quite often, great of increasing DOF for static objects....

BTW, DOF never changes at the same end magnification.... often mis understood... it does not matter how you get there, i.e. a single objective or a series of lenses.

I will have to tackle this when I have time, cause I can tell it will be another OCD project... utlimately, the ideal set up would be a great miscroscope with an imaging sensor on it, but since they are low volume, the cost would be quite high, hard to justify since my sharpening is quite good already.... and I have learned that even using my Shapton 30k stones, the finder edge, as remarkable as it is, only lasts a shortwhile till it falls to 15k sharpness..... but at times, that added sharpness is sure appreciated...

some snaps of what your edges look like would be great....

[Stuart Tierney]

The depth of field doesn't change, but the sharpness of image without the mediocre eyepiece certainly does.

Another nice point about using the reflected light is that once you're dialled in, never need to touch any of it even when changing objectives. But I still need to tweak and tune the objectives I have so they'll all pop into focus as I switch them, or as close to it as I can manage. While the glass from India was nothing special, at least they focused well together. The Chinese stuff is obviously better made (is that possible!?!) but they're miles apart from each other in focusing distance. Bad enough that switching from 20x to 40x means backing off the head otherwise the 40x objective will bump into the subject.

And I need some oil too. Apparently the 100x is an oil objective, even though it works moderately well without it. Might try a little mineral oil. Can't hurt anything and might be enough for my needs.

I have a big day ahead of me, but over the next week or so I'll try and get some images up either here or on my blog.

Never used a Shapton 30,000. I can't justify the cost and have trouble finding out whether it's going to be of that much benefit anyway. Not forgetting that for the same money I could buy a heck of a lot of natural stone or even have a stone made to spec if I wished.

And I'm paying a heck of a lot less for Shapton than most folks here too. ;)

Stu.

[Chris Fournier]

Not to press a point too hard but the surface quality of the wood you are working will scream out sharp/not sharp as will the effort to push the blade through the wood and if that isn't enough then listen to the blade as it moves through the wood. The cost to you for all of these indicators of blade sharpness is zero.

I think that the poster who said that this endeavor is a sub-hobby within a hobby has it right - nothing wrong with that but requiring 80X magnification to determine a cutting edges sharpness while a quick visual inpsection of the wood would suffice seems a bit wrong headed if woodworking is your pursuit.

Would you judge a surgeon's work by how much attention she pays to the edge of her scalpel under magnification? I certainly would, and that would be one surgeon I'd take a pass on. I do not intend to infer that you are not a good woodworker by the way!

[Stuart Tierney]

Not to press a point too hard but the surface quality of the wood you are working will scream out sharp/not sharp as will the effort to push the blade through the wood and if that isn't enough then listen to the blade as it moves through the wood. The cost to you for all of these indicators of blade sharpness is zero.

I think that the poster who said that this endeavor is a sub-hobby within a hobby has it right - nothing wrong with that but requiring 80X magnification to determine a cutting edges sharpness while a quick visual inpsection of the wood would suffice seems a bit wrong headed if woodworking is your pursuit.


Chris, don't get me wrong here since I do completely and utterly understand your point, and never inspect any of my own edges that I plan to use. I know they're sharp, and that's enough.

However, plenty of folk out there don't have even 1/100 of what I have at my disposal for education, sharpening equipment or intuition (I'm one of them nasty monkey see-monkey do better than most people) and there is absolutely no question that seeing what's going on at the very edge and from that information deducing what's being done incorrectly whilst sharpening is valid, and a very good idea.

Perhaps not for everyone, but I've taken a few minutes from my busy to point out what 'seeing the edge' can show.

This is an LN #164 blade, sharpened with a Shapton Glass Stone #16000. Hand it to anyone, and they'll say "it's sharp!".

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Looks decent, reflects light nicely, heck it's sharp.

But under 40x magnification...

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Doesn't look so hot now, does it? Maybe I should spend some more time on the stones? But hey, it's sharp right? Still can't work out why it won't cut figured wood cleanly nor why the edge fails earlier than it should, but at least I might have an idea now.

But at 200x...

207567

Oh dear. Seems like it wasn't actually as sharp as it promised to be. Quite clear that somewhere along the line I decided that 'polished' actually meant 'sharp' and it actually wasn't anything of the sort.

Or maybe the stone is contaminated? Maybe I'm not doing something right? I don't know right now, but now I can see what's happening I might be able to fix the problem quickly.

You don't scratch your head wondering why your dovetails won't close up from across the room, you stick your nose in there and have a look.

Now I'm not saying everyone should rush out and buy a microscope because it will make you a better sharpener, chances are it might be of any benefit at all to many folks, but in the right hands it's just another tool, a diagnostic tool that may help weed out problems you don't know are occurring, but are only familiar with the symptoms.

I have this gear because the shelf under where this microscope lives is filled with sharpening stones, all stock. I sell them, and need to be able to show folks, in detail, what xyz stone can do and why it does what it does. I'm not content with simply saying "buy this stone, it's the best!" without being able to comprehensively back up my opinions with hard evidence. And even then, "the best!" is subjective and heavily dependent on who's using the sharpening system and what they want from it.

So please, Chris, just because you can't see the value in having a small, $10 microscope to see what's happening doesn't mean the value is not there.

And really, what's $10 if it helps solve hours of frustration and confusion?

Stu.


Disclaimer, this is not a slight on the Shapton #16000 Glass Stone. The problems were in place (deliberately) before that stone had a chance to do anything worthwhile. I only mention the stone used as an example, nothing more.

[Will Blick]

> And I'm paying a heck of a lot less for Shapton than most folks here too

ahhh, care to share? :-()

I was really curious what the post count would be, till someone finally steered the discussion towards "how does this relate to ww".... well, 23 is not too shabby, much better vs. previous years where the post count would not even make it to 10. It seems people get annoyed that some of us are obsessed with sharpening....

[Will Blick]

Stu, excellent post...its a shame you feel compelled to justify what you are doing. But I get it. Regardless, many of us appreciate exactly what you are doing, so please never get discouraged....

So do you sell sharpening supplies? If so, I commend your efforts going the extra mile. and great write-up with the pix, well done.

I plan to buy a 200x Peak loupe next as 100x is not sufficient, although its a good start.

Although the situations are rare, I have planed some end grain that was so nasty, that it required my best sharpening skills, all the way up to 1/4 micron diamond dust in baby oil.... finally I got the paper smooth cuts I desired...of course, the edge did not last long, maybe 10 - 12 swipes.... It was rewarding knowing that all this came together, knowledge paid off...

This is one of the conclusions I have come to about sharpening... the sharper the edge, the thinner the metal at the tip of the edge....thin edges are SHARP and vulnerable at the same time, as it easy to knick very thin metal... so ultra sharp blades on wood never last very long.... they fall down the sharp scale with low usage...how fast depends on the wood.

[Matthew Hills]

I'd think some magnification would be useful for checking what type of unsharpness you have -- whether the steel is folding or chipping, etc.

Derek Cohen has a few posts in which he shows pictures from his Digital Blue series QX5 (although he didn't seem too thrilled with the outcome): http://www.inthewoodshop.com/ToolReviews/ChiselParing.html

Matt

[Dan Hintz]

Here here... I'm enjoying this thread, because I'm the same type of Monkey Stu mentioned. I looked for a good miscroscope to do exactly what has been outlined here, but I couldn't find one I was both happy enough with the specs and happy enough with the price.

[Chris Fournier]

So please, Chris, just because you can't see the value in having a small, $10 microscope to see what's happening doesn't mean the value is not there.

And really, what's $10 if it helps solve hours of frustration and confusion?

Stu.


How'd you come up with the economical price of $10? That's not the price that's been talked about here. I have loupes and magnifiers and they all cost more than $10. By all means have a jab at me but it need not be absurd!

[Stuart Tierney]

How'd you come up with the economical price of $10? That's not the price that's been talked about here. I have loupes and magnifiers and they all cost more than $10. By all means have a jab at me but it need not be absurd!

Well, the microscope I use for 'work' (is it still work if much of the time it's actually fun?), all up, has probably a 4 figure sum tied up in it. Again, it's all paid for and it's going to earn it's keep otherwise I'd never have bought the danged thing.

But the little pocket microscope I have is informative enough to show where things might be going wrong and it cost me under $10. 998 yen IIRC when the dollar was worth 110 yen, and I didn't have many of either. Punch 'pocket microscope' into ebay and there's hundreds of the things, all more than sufficient for the task asked about here, and that's what the original question alludes to.

The little one I have is not as clear as my proper unit, nor does it have the level of magnification and you can't hang a digital SLR camera off it, but the little thing tells enough to help pinpoint problems.

The picture I borrowed in my first post in this thread sells for the grand sum of <$10, including shipping.

The rules here don't allow me to link to ebay directly (and if they in fact do, I'm not going to anyway) so I can't hold your hand here any more than that.

If you can't stretch the budget that far, I'll send you one on my coin. :)

(Silly things are under $5 from some places...)

Stu.

[Chris Griggs]

Punch 'pocket microscope' into ebay and there's hundreds of the things, all more than sufficient for the task asked about here, and that's what the original question alludes to.

The little one I have is not as clear as my proper unit, nor does it have the level of magnification and you can't hang a digital SLR camera off it, but the little thing tells enough to help pinpoint problems.

The picture I borrowed in my first post in this thread sells for the grand sum of <$10, including shipping.



Just did the search - this one is only $5.79 shipped. Wonder if it's worth a darn. For under $10 perhaps I will order one - could come in handy when working backs...

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[bill tindall]

As important as the microscope is lighting. Elliot gets the useful information from his images through clever lighting. The lighting can also delude one into thinking they see some feature, or not. Even with a $30,000 scope the image can be less informative than Steve's if not lighted optimally. I have worked with the people in a large industry microscopy lab and the results have been more dependent on the skill and equipment for lighting than the scope.

BTW, you can't image something with a size approaching the wavelength of light. So forget imaging the scratch pattern or edge of a highly refined tool edge. In my hands the limit with a Nikon metal imaging scope is a few microns. It is for this reason that Lee Valley has purchased an electron microscope to support their sharpening research.

[Russell Sansom]

Two comments:
1) I find the cheap microscopes worthless at best. Their optical quality is simply too poor. I also find the hand-held / pocket versions surprisingly awkward and difficult to use. They require a jig to hold the edge ( there is some danger to your fingers ), if nothing else, to keep it registered in the same plane as the optics. This is really hard to do with hands alone.

I tried a Mitutoyo 25X inspection microscope model 183-202 (you can see it on Amazon). It is beautiful to hold and quite nice for looking at wood grain and flat objects, but if you reach out to focus it...the game is over as the scope and the object under scrutiny move around. Upon reflection, I'll revise "surprisingly awkward" to "almost impossible." And you have to focus it to look at an edge in 3-d. Also, lighting needs to be the same, edge to edge, viewing to viewing. So, again, without a jig ( well, several ), even this outstanding magnifier is just too unwieldy for looking at sharp edges. (Don't get me wrong, it's fantastic for looking at what it was designed for )

2) The StereoZoom 4 ( sold by several big names ) doesn't have the high power. At .7x to 3X with a pair of 15X eyepieces it zooms up to 45 power. The optics come as a sort of "pod" and show up with a variety of stands from booms to the simple thing in the picture.

For the purposes of assessing failures and just getting an up close idea of what sharpening has done, these kinds of powers are ideal. The working distance is 4", so it's possible to put almost any working steel under the lens. I found mine from a local guy who bought a warehouse full of them. I think out the door with illuminator was about $235. Looking on Ebay, this is probably a very good price, but they are around. Here in Silicon Valley, they show up on Craig's list fairly regularly. I wish I had a digital camera adapter for one of the eyepieces.
This is a little different from what Stu and Derek have done, but not that much. The zoom and quick set up make this thing perfect for getting in the loop with microscopic edges. It doesn't drill down to a magnification where things seem hopelessly ragged, but I'm not doing testing in that sense.

3) I don't know about the "you don't have to do this" comments. My tools were square, uniform, and perfectionist-sharp. But I wanted to find and understand "sharp" at some level beyond "I can just tell." This route worked quite well for me.

[Will Blick]

Russell, to see anything substantial for sharpening, you need to be in the 75-200x range...

excellent comments on lighting.... its often the missing link, many don't understand this. What we see in on the edge is tiny differences in contrast.... the brighter the light, the higher the contrast that is projected onto our foveal.... also, our eyes are at max. acuity, when our eye pupil is dilated down to 2.5-3.0mm range, same as daylight forces. At wider pupil diameters, our acuity is about 1/6th this...the eye has its own MTF curve just like any optic. So for best possible view, BRIGHT is the cheapest method to increase acuity as it makes your 6x more sensitive to contrast for visual optics of course, not electron microscopes. Then, add in the quality of the optics.... optics are measured in the amount of subject contrast they can transfer through the optic. A low quality optic may transfer 10% of the subjects contrast, while a high quality optic can transfer 90% or better (based on size of the subject), hence why its graphed on an MTF curve (Modular Transfer Function) .... this is why you can buy a $25 pair of Chinese binoculars, and a similar size from Zeiss for $4k. But lighting is KING, and the biggest bang for the buck.

[Chris Fournier]

Well, the microscope I use for 'work' (is it still work if much of the time it's actually fun?), all up, has probably a 4 figure sum tied up in it. Again, it's all paid for and it's going to earn it's keep otherwise I'd never have bought the danged thing.

But the little pocket microscope I have is informative enough to show where things might be going wrong and it cost me under $10. 998 yen IIRC when the dollar was worth 110 yen, and I didn't have many of either. Punch 'pocket microscope' into ebay and there's hundreds of the things, all more than sufficient for the task asked about here, and that's what the original question alludes to.

The little one I have is not as clear as my proper unit, nor does it have the level of magnification and you can't hang a digital SLR camera off it, but the little thing tells enough to help pinpoint problems.

The picture I borrowed in my first post in this thread sells for the grand sum of <$10, including shipping.

The rules here don't allow me to link to ebay directly (and if they in fact do, I'm not going to anyway) so I can't hold your hand here any more than that.

If you can't stretch the budget that far, I'll send you one on my coin. :)

(Silly things are under $5 from some places...)

Stu.

I can say that you are truly generous and actually mean it all the while saying it tongue in cheek on this one Stu! Well done by you! Your offer is very kind but I am waiting for my next visit to the optomotrist where I will intentionally do miserably on the test and end up a beautiful pair of "coke bottle" glasses that will help me pick out inferior cutting edges from across the shop. I'll just have to make sure that I don't look at wood with a strong sunlight behind me...

[Stuart Deutsch]

For low-cost and easier view than a small loupe, an illuminated magnifier would be alright. A higher-priced inspection microscope like the ones shown above would be great. An inverted-stage optical microscope would be "best", especially if it has an adjustable polarizer and maybe even dark-field light source. I used such a scope for preparing metallurgical samples for analysis, and it makes polishing defects pop out like crazy.

An electron microscope would be realistically unfeasible even if you have access to one due to maximum sample size limitations, but I've seen some great images of sharp vs. dull chisels before.

[Bill Nenna]

I have thought about the same thing. I would like to examine the advantages and or disadvantages of stropping. I heard David Charlesworth say he likes about 50x to examine edges. From the photos shown here I would say that would seem to be good.

By the way, for anyone that has 35mm photo equipment around, a wide angle lens held reversed makes for a high quality loupe! The wider the lens, the greater the magnification.