Measuring and testing equipment

yuzuha said:
These aren't too bad for a larger 16x magnifier http://www.frostproof.com/catalog/m37.html
They have a nice lens size comparison chart too http://www.frostproof.com/handlens.html the 12x Eschenbach Doublet has a decent size lens too

Edmund has Hastings triplets but, like B&L, their lenses are a bit smaller than others. They do have 6x direct measuring comparators though...
http://www.edmundoptics.com/onlinec...d90016de5-2C83AB43-3048-41AD-8456B2C437E5D476 that allow you to measure things optically
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yuzuha,

Thanks for doing the legwork to find all of these sources for magnifiers. One thing I keep running into is aplanatic and achromatic lenses - it seems that a lense can be either one, but not both. Is that correct? If so, which would be more appropriate for this application (I'm thinking aplanatic)?

I have very little experience with magnifiers and optics, so I'd not be surprised to find out that I am totally wrong! :)

Thanks again,

Matthew
 
Starfish said:
yuzuha,

Thanks for doing the legwork to find all of these sources for magnifiers. One thing I keep running into is aplanatic and achromatic lenses - it seems that a lense can be either one, but not both. Is that correct? If so, which would be more appropriate for this application (I'm thinking aplanatic)?

I have very little experience with magnifiers and optics, so I'd not be surprised to find out that I am totally wrong! :)

Thanks again,

Matthew
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Well, they are talking about two different things... aplanatic lenses have two or more lenses that are shaped to reduce spherical abberation and coma. Achromatic lenses are designed to reduce color fringing (the speed of light in glass is dependant on the wavelength and the edge of a lens is like a prism. Lenses of different shapes made of glass of differing refractive indexes are used to attempt to focus both the red and blue end of the spectrum at the same point). Those real cheap dimestore telescopes don't have the best optics and you and often see both types of flaws in them... stars will not focus to a point and may become elongated or comma shaped near the edges of the field of view and they may show differing colored halos around them. The best lenses try to elimiate both types of error.

BTW, Kingsley North also has a nice wide selection of hand lenses too... two pages here http://www.kingsleynorth.com/skshop/search_results2.php?catID=310 and two more pages here http://www.kingsleynorth.com/skshop/search_results2.php?catID=316
Hastings triplets are generally more expensive but are very good at correcting both spherical and chromatic abberation. Some companies have tried to improve on the design and may have their own pet names for their lenses. Coddington doublets aren't as good but they are cheaper and do a reasonable job of correcting both types of abberation. Beware of the real cheapo lenses though as a well made Coddington etc. will outperform a poorly made Hastings triplet.
 
yuzuha,

The magnifiers that you have linked to range in price from $15-$55. What differences can I expect to find in that range? Does the lower price manifest itself in more distortion, poorer build quality, etc?

Thanks for all of your help,

Matthew
 
Jeff Clark said:
If you are doing nice flat edge bevels you might try a laser pointer for measuring the bevel angle:
http://www.bladeforums.com/forums/showthread.php?t=130205
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Interesting read! And it makes me realize that owning a pair of calipers is not enough for measuring the edge angle! I suppose though that other measurable factors will provide useful information, i.e. edge thickness and edge height.

Any other suggestions for data collection?

Thanks,

Matthew
 
I just picked up that $7 magnifying glass from Radio Shack. Wow!! I've only checked out a couple of knives, but I'm finding that my EdgePro sharpened knives have a much smoother bevel, but there are more nicks in the very edge than two factory edge Camillus knives. This reinforces my previous conclusion that Camillus has one one of the best factory edges. Either that, or I still haven't figured out how to correctly use my EdgePro!

And the tip of my CUDA Maxx, which has the pointiest tip of any knife I own, looks dull and rounded under the magnifying glass. I wish I had a syringe or scalpel for comparison purposes. Anyway, well worth the $7 at your local Radio Shack, and radioshack.com will tell you if your local store has them in stock.
 
AlonzoMosely said:
I just picked up that $7 magnifying glass from Radio Shack. Wow!! I've only checked out a couple of knives, but I'm finding that my EdgePro sharpened knives have a much smoother bevel, but there are more nicks in the very edge than two factory edge Camillus knives. This reinforces my previous conclusion that Camillus has one one of the best factory edges. Either that, or I still haven't figured out how to correctly use my EdgePro!

And the tip of my CUDA Maxx, which has the pointiest tip of any knife I own, looks dull and rounded under the magnifying glass. I wish I had a syringe or scalpel for comparison purposes. Anyway, well worth the $7 at your local Radio Shack, and radioshack.com will tell you if your local store has them in stock.
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Hi Alonzo,

Thanks for your input. I think I'll swing by tonight and pick one up just to see. I will probably still pick up a 10x or 12x loupe but, for $7 I haven't got much to lose with this :)

Matthew
 
Starfish said:
yuzuha,

The magnifiers that you have linked to range in price from $15-$55. What differences can I expect to find in that range? Does the lower price manifest itself in more distortion, poorer build quality, etc?

Thanks for all of your help,

Matthew
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Yes. Some are made of solid brass and built like a tank, some aren't built as well, some use a plastic housing to cut the costs but otherwise have good optics. The good ones will have a clear undistorted image from center to edge, the cheaper ones will have a clear image in the center but the edges may distort some (some have a diaphram in them so you aren't distracted by the distortions near the edges and will perform like a higher quality loupe with a smaller lens). http://www.njminerals.org/loupes.html You should be able to find a decent one for about $20 (some are more expensive than need be because of the brand name and sometimes you want a cheap <$10 "beater" as the web site I just listed mentions) This place has the 10x Belomo's on sale http://www.geo-tools.com/lens.htm
 
AlonzoMosely said:
I just picked up that $7 magnifying glass from Radio Shack. Wow!! I've only checked out a couple of knives, but I'm finding that my EdgePro sharpened knives have a much smoother bevel, but there are more nicks in the very edge than two factory edge Camillus knives. This reinforces my previous conclusion that Camillus has one one of the best factory edges. Either that, or I still haven't figured out how to correctly use my EdgePro!

And the tip of my CUDA Maxx, which has the pointiest tip of any knife I own, looks dull and rounded under the magnifying glass. I wish I had a syringe or scalpel for comparison purposes. Anyway, well worth the $7 at your local Radio Shack, and radioshack.com will tell you if your local store has them in stock.
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I'm glad you tried it out... I was hoping the guy who said it was 'way too much' magnification, didn't turn everyone off. I think it's a great tool... and can't beat the price.
 
Starfish said:
Interesting read! And it makes me realize that owning a pair of calipers is not enough for measuring the edge angle! I suppose though that other measurable factors will provide useful information, i.e. edge thickness and edge height.

Any other suggestions for data collection?
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It depends on your budget, level of accuracy required and amount of data required. To really be aboe to accurately measure blade bevel angles at a minimum you'd need a precision protractor. A nice optical comparitor would help, but I'd think a granite inspection plate, a sine plate, a height gauge and an inspection indicator would be needed. If you were really good at trig you could probably do without the sine plate and use some sort of flat precition fixture that would allow you to at least hold the blade in a repeatable position. Maybe a small precision ground toolmaker's vice sitting on the inspection plate would do to hold the blade while you used the height gauge to do the measuring.

If you looked around for the right deal on used stuff, or bought cheap Chinese stuff you could probably get a small inspection plate, height gauge, toolmaker's vice and inspection indicator for less than $200.00. Rally good Swiss or American made tools could easily run a few grand to do the same tasks.

If you have the cash and need to measure a bunch of cool 3d shapes precisely, the market seems rife these days with very cool coordiante measuring sytems like Browne & Sharp Validators at unheard of prices as our manufacturing infrastructure continues to collapse and we ship all manufacturing to China. These use a physical probe riding on an air bearing supported trusswork, floating over a precision ground big hunk of granite.
You can use these things to measure all sorts of stuff by giving it a command and then guiding the probe to different areas of the item you want to measure.

Truly amazing measuring gear.

John
 
cbwx34 said:
I'm glad you tried it out... I was hoping the guy who said it was 'way too much' magnification, didn't turn everyone off. I think it's a great tool... and can't beat the price.
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I tried it out last night. Perhaps I need more practice with the magnifier, but I found it difficult to even point the lens onto the edge let alone focus on the edge.

I'm inclined to believe that 60x, while perhaps not 'way too much' magnification, is better for more experienced hands.

Matthew
 
Matthew - maybe yours is defective? Mine gets a real nice clear image and I have zero experience with these things. I can't believe its only 7 bucks. The only tricky part that I found is that the image is inverted so to follow the edge to the tip of the blade looks like in the image that you are going in the wrong direction. Maybe if you have a book the width of the knife handle, you could support the blade with the book so that it is laying flat against something solid and you could maybe tape it so you don't knock the blade around with the magnifier while you are trying to focus?
 
Starfish said:
I tried it out last night. Perhaps I need more practice with the magnifier, but I found it difficult to even point the lens onto the edge let alone focus on the edge.

I'm inclined to believe that 60x, while perhaps not 'way too much' magnification, is better for more experienced hands.

Matthew
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Set it on a flat surface, and focus on that... then you can set it flat on the knife. It works better if you have the microscope running the same direction as the edge (if that makes sense).
 
I didn't say that 60x wasn't interesting. Just that unless you have an industrial grade stereomicroscope set up near your sharpening station, that cheap microscopes were a pain to use and impractical for checking your progress (and even a lab grade one would not really be practical for checking your progress while sharpening because of the small area of focus and shallow depth of field and you'd have to step away from your stones and take the time to focus and all that... save it to admire your handiwork after you are done). Until you learn to read the reflections as HoB mentioned, you can easily grab a loupe and check your progress in a second, (particularly if you have it hanging on a cord around your neck).
 
I tried again with the Radio Shack microscope and was more successful this time. I looked at a BM 941 that has not been used very much, and my well-used SAK Soldier. Quite a bit of difference between the two!

As noted by yuzuha though, it did take me some time to get the microscope focused onto the edge, so I believe that a lower-powered loupe with a wider field of view will be more helpful during the process. Yuzuha, thanks for posting the link to that page describing loupes. I went ahead and purchased a 10x Belomo since it appears to be a great value for the money!

Thanks,

Matthew
 
Hmmm... well now I'm gonna have to see about getting one of the loupes and try it out. I always thought the microscope worked well, but heck.... I may just not know any better.
 
cbwx34 said:
Hmmm... well now I'm gonna have to see about getting one of the loupes and try it out. I always thought the microscope worked well, but heck.... I may just not know any better.
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cbwx34 -

I could see the edge fine, it just took me a bit of time to get everything lined up. As yuzuha said earlier, I'd rather do that when I want to admire the end result -- assuming I can do well enough freehand to have something to admire! :)

I imagine that given enough practice, I could probably use the 'scope and nothing else. Probably just have to get over that feeling of disorientation due to the inverted image!

If you do end up getting a loupe, I'd recommend the people at the last link yuzuha provided. The loupe at that link seems to have a good reputation, and it only cost me a little less than $17 with shipping. Plus the guy who runs the store was quite helpful!

Take care,

Matthew
 
Cool, post again when you get it and let us know how you like it. (for that price I'm thinking of getting one myself even though I've already got a 10 and 16x coddington)
 
Will do...!

By the way, while searching on another topic, I found the following quote:

That Radio Shack magnifier number is for *AREA* magnification, the other numbers quoted in the above for the loupes and such are linear magnification. In the same scale the Radio Shack magnifier is up to 10x .
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That's from Cliff Stamp, in this thread.

Matthew
 
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