Sharpening - Loupe / microscope / magnifying aid

[bushtucker]

I've tried the microscope from Radio Shack, a stereo microscope (expensive) and various magnifying glasses to help me inspect my blade bevels for micro-bevels and burrs, and gloss from stropping.

The results of my experimentation is that one product stands above the others in usefulness. It's the Bausch & Lomb Hastings Triplet Magnifier 20x. It incorporates three separate high quality glass lenses, bonded together to form a compound lens to provide sharp, very distinct magnified image without distortion. Although tiny, you hold it close to your eye and the image is very large, very sharp, edge to edge, and as clear as an expensive microscope. This is a professional tool usually used by jewellers. I love it!

Highly recommended for blade fanatics and OCD sharpening freaks. :thumbup:

 

[fdd19]

43 dollars huh not bad

 

[bushtucker]

You have to pay for quality, unfortunately. The radioshack microscope is a cheaper alternative at $10, but it is all plastic and the image is inferior. Also not as easy to use (darker image) and much less transportable and less rugged.

 

[bushtucker]

The 20x is very small, so .....

ALWAYS ATTACH IT TO SOMETHING UNLESS YOU WANT TO LOSE IT!!

 

[bushtucker]

Just a note about triplet lenses: cementing three lenses together produces a triplet lens. Triplets produce a better quality image, have a flatter field, are color corrected, and give very little or no image distortion. Triplet lens systems are best used for applications that require a great deal of precision at high magnifying levels. HTH.

 

[bushtucker]

But if you are a real knut with terminal sharpening addiction and lots of cash, you can't go past a proper stereo microscope, $350.

LW Scientific - Achiever Stereo (20x40) on dual light stand

 

[1whitefoot]

Hey thanks for doing the research. :thumbup:

I've been wondering what kind to get.

 

[yuzuha]

Yep, that is why I've been steering people to the BeLOMO 10x triplets rather than the plastic toy microscopes... they're a bit cheaper than the B&Ls too (so people won't balk too much at the price) and a bit larger than the B&L's and also have very good quality Russian glass. They now also make a 20x but they are sold out at the moment http://www.amateurgeologist.com/products/belomo-20x-quadruplet-loupe-magnifier.html

 

[sasu]

This is what an edge looks like through one of those 20x loupes.

The loupe itself.

The next step for me will be a microscope. I am curious to see ever more details of the edge.

 

[bushtucker]

Nice photos there! I'm surprised that the photos seem so low magnification though ... my B&L 20x magnifies more than that, much more. It may be a function of using a camera, and trying to juggle focus and distance, perhaps? Or perhaps it's not a triplet lens?

 

[mete]

Mine is larger than the B&L and I've had it for many years and used it for many things. It's only 10x. Remember that the higher the magnification the shorter the DOF. The radio shack type is cheap because everything is plastic including the lens, it's not worth any more than $10.Get a good one and it will be used for the rest of your life !

 

[FlyingMuskrat]

I have on of these. It does pretty well. Here are some pics I took through it.

 

[bushtucker]

FlyingMuskrat, that sort of microscope is fine, but it's definitely inferior for this sort of application to a stereo microscope. I know, I have both kinds.

 

[yuzuha]

Here's an edge on shot of a fresh scalpel / xacto type blade

Here is the main bevel and microbevel from the side (non surgical so came out of the box pretty dirty)

Note, at this scale the microbevel is about 1/128th's inch wide

 

[matt321]

yuzuha,
I'm curious...
Is it possible to deduce the manufacturor's abrasive grit by counting the ridges in the photo for a 1/128th-inch width and then doing some math?

 

[Broos]

Taking the scale to my computer screen, I'm getting 25 or 26 grooves per 1/128".

So 1/128" / 26 grooves = .0003005" inches per groove

1" = .00254 meter ; 3.005E-4 inch = .00000763 m ; .000001m = 1 micron

I'll guess 8 micron abrasive.

And cool pics!

 

[matt321]

Coool Broos.

That would be a 1500 grit waterstone...similar to a Sharpmaker fine or a black or translucent Arkansas stone based on Chad Wards grit table.

 

[yuzuha]

yuzuha,
I'm curious...
Is it possible to deduce the manufacturor's abrasive grit by counting the ridges in the photo for a 1/128th-inch width and then doing some math?

I suppose you could but it would be a lot easier if I had a reflected light stage micrometer to calibrate everything but they're around $200. (it is basically a precision metal ruler with graduations every 10 and 100 microns... I could use it to calibrate my camera software and then I could just drag a few lines over the image and it will tell me how big something is without me having to do a bunch of guess-timating, math or pixel counting)

My scope isn't particularly useful for checking burrs though since the light comes out of the objective, reflects off the object and back into the objective so what you are looking at has to be pretty flat on the stage to reflect enough light (that edge on view is mighty dark and noisy) and cope with the shallow depth of field. You'd need some sort of jig to hold something like a folder so that the microbevel was 90 degrees to the objective lens. Maybe a picture would help explain what I mean (the screen is displaying a captured image, but an object needs to be flat like the little piece of paper that I have over the hole in the stage to keep dust from falling onto the objective lens)