Is 600x microscope sufficient?

[SHARPCO]

OK... so, we need to make Grepper's post on 'scopes the beginning of a sticky topic if possible. Please. That's a Fabulous post my friend.

I have had a Veho 400 USB scope for years, but I gotta tell ya, it's seen virtually no use. I can see the LOW plainly and waaay quicker with my 80x toy microscope. If you make a pass and want to see exactly what happened on that pass, how long does it take to absolutely inspect the entire edge with a USB 'scope? What if you're inspecting every pass on a blade... like 10- 20 passes per side?
   
I may not understand, but is there an issue with the LOW? Do we know exactly what we're seeing?

I don't know much about LOW. 

I have a 10X loupe and I believe it couldn't show me LOW and micro burr. 

I'm not having trouble removing the burr, but I want to make sure it is completely removed.

[Mark Reich]

I just checked a very good 10x loupe, and it's pretty difficult for me to see what's happening to a small burr. That's what you have to be able to see. Ideally, you need to see it well enough to identify exactly what you're seeing, IMHO.

I am curious to know if anyone with a real microscope can see what the LOW is.

[grepper]

What has been dubbed "LOW" for Line of Weld because that is what it resembles, is a piling up a metal at the base of the burr.  Maybe this is what some folks call a wire edge?

It looks like this:

   

If the flimsy part of the burr above it is removed it looks like this:

   

It is a piling up of soft crappy junk metal at the base of a burr that actually extends down from the edge over the bevel.  And, it's stuck there quite firmly.  A leather belt won't remove it but instead just polishes it.

How do I know this?  I pushed the tip of an Exacto blade up the side of the bevel until it impacted the bottom edge of the LOW.  I was then able to push the pile of metal off the bevel and over to the back side of the blade.

I put the tip of the Exacto knife where the red arrow is a pushed up the side of the bevel.  You can see how the pile of LOW crud was pried from the side of the bevel and pushed over to the back side of the blade, exposing the true, nice and toothy edge it concealed.

   

If you don't know it's there, LOW is a problem because it can actually be sharpened to a very sharp edge, but it's crap metal, so you have to find a way to remove it.  Because it's soft junk metal it's easy to get it really sharp and it can fool you into thinking you have a beautiful super sharp edge when really it's just sharpened crap on top of the actual hard edge of the blade. 

Mr. Sharpco, these images were all taken with:
https://www.amazon.com/Celestron-Handhel...B00CMJ1I08

[Mark Reich]

YES!! Good answer, Mr Grepper! I love the last picture. I can hardly believe you can deburr with an exacto knife, but it looks like you did exactly that. It looks like you "cut" the burr completely off! Wow! It's amazing to see how much "height" you took off the edge to reveal the scratch pattern.

As you say, right under the LOW is a perfect scratch pattern. That is exactly what I've been thinking. You're right, I could not get a plain leather belt to affect the LOW either, so how you've been finishing on bare leather has been a real source of wonderment for me. 4µ diamond compound on a leather belt makes a huge difference. You can totally remove the LOW in just a few passes, without generating much, if any burr on the other side.

Will the diamond compound kill the tooth? Yes, of course. 4000 grit will do that, but the point is getting rid of the LOW quickly and completely. It only takes a few passes of the deburred edge across a coarse stone to give the edge all the tooth you want.

To me the LOW is just the base of the burr, and it's on the burr side of the blade Only. The other side is always clean, but depending on how you remove the burr, you can create another burr on the other side. Deburring on a stone makes things easier to see and identify IMHO.

[grepper]

Yeah Mr. Mark, I did that when I was trying to figure out exactly what I was looking at under the scope.  The base of the burr looks like a bulbous lump but I was not sure.  So I did the Exacto knife thing and sure enough I could feel resistance when the the tip butted up against that cud and when I pushed it tore it off the edge and pushed it over to the other side of the bevel.  I took an image of it and it looked exactly like the third picture... (more shortly).

That was when I realized LOW is actually what it looks like and not just some strange light reflection caused by scope lighting.  It's actually a lump of crud, and it's stuck there pretty firmly.  It's not like it's actually welded on, but it's stuck well enough that you must actually be able to grab on to it, or hook it to pry it off. 

It's very similar to a bead of glue stuck to the side of a blade.  It's stuck well enough so it can actually be worn down, polished and shaped by smooth things, but when a razor blade or screwdriver blade is pushed against the side of  it the thing will just pop off. 

There are two ways to remove it; grind it away, or find something to grab onto it and break it off.  As you say fine abrasives work but they smooth tooth.  I wanted to preserve the beautiful toothy edge so I went in search of something that could grab onto that crap and break it from the edge but not smooth the toothy edge.

I tried just about every surface I could find; hard / soft rubber, Formica, thermoplastic, sandpaper, wood and many other stuffs.  Lots of different stuff.  Nothing worked.  I had about given up when I spied a well worn very fine Scotch-Brite belt hanging on my belt hanging thing. 

So by hand, using light moderate pressure I dragged the blade for about an inch or two over the belt and took a picture of it.  To my surprise it worked.  That Scotch-Brite surface grabbed the LOW and broke it off but didn't remove any of the wonderful toothiness.  Looking at the third image again I see diagonal scratching on the bevel that is not present on the part that is not deburred.  Because of that scratching, I now think that image may from the Scotch-Brite rather than the Exacto.  It makes little difference as the results were the same.   I didn't mean to misrepresent what the picture actually was, but apparently I didn't find the one I did with the Exacto blade in the hundreds of blade images I have.  But like I said it makes little difference.  It was, after all, using the Exacto blade test that demonstrated exactly what LOW is and why I went on a search to find something that could duplicate what it did and pop that LOW junk off the edge.  If I can find the actual Exacto image I'll post it, but it looks just like the one posted only without the scratching of the bevel below the burr.

Now I always do preliminary deburring with a well worn very fine Scotch-Brite to bust the LOW and then switch to leather.  But, deburring with Scotch-Brite is sort of a learned thing.  A too new belt, or to coarse a belt, or too much pressure or time spent will quickly mangle the edge .  It takes a bit of practice to figure it out, but when it works it's amazing, and best of all, it preserves tooth.

[SHARPCO]

If you don't know it's there, LOW is a problem because it can actually be sharpened to a very sharp edge, but it's crap metal, so you have to find a way to remove it.  Because it's soft junk metal it's easy to get it really sharp and it can fool you into thinking you have a beautiful super sharp edge when really it's just sharpened crap on top of the actual hard edge of the blade. 

Mr. Sharpco, these images were all taken with:
https://www.amazon.com/Celestron-Handhel...B00CMJ1I08

Thank you grepper. 

First of all, Celestron handheld microscope is looks good. I like the performance as well as the price. 

BTW, if the LOW is very difficult to remove, do you think it is impossible for people who don't have a power tool like belt grinder to remove it completely?

[grepper]

Mr. Sharpco, I edited my post and babbled - "Looking at the third image again I see diagonal scratching on the bevel that is not present on the part that is not deburred.  Because of that scratching,  I now think that image may from the Scotch-Brite rather than the Exacto.  It makes little difference as the results were the same."

Also I originally uttered, "So by hand, using light moderate pressure I dragged the blade for about an inch or two over the belt and took a picture of it.  To my surprise it worked.  That Scotch-Brite surface grabbed the LOW and broke it off but didn't remove any of the wonderful toothiness."

Additionally, Mr. Mark stated he can do the same with a stone.

So no.  Power equipment is not needed.

[Mark Reich]

I think you have the right picture, Mr Grepper. That single, deep scratch has to be from the exacto blade, if that's what you're talking about.

What little I've done with the Scotch-Brite does seem to work, but I need more practice...