Stroping Question

[Anonymous]

What grind marks are you talking about.? I don’t spend 6 or seven hours to get a mirror finish like expressed by professionals in this forum who are saying a  true mirror can takes that long.

When  your final edge is 1500 grit, when you look at it under a microscope, it has scratches, even at .5 microns there are scratches, scratches have high and low points, otherwise they would not be scratches. the high point and the low point of even .5 microns, capture black marker in the high spots and the low spots. if your swipe stone does not reach the low points of the edge they remain black.. once  you remove all the highs and you edge is totally at .5 microns, there are no more scratches and the sharpie will work.. if the edge is #600 grit but still razor sharp the scratches are deep by magnified standards.

to say you keep using the stone until all the scratches are gone, is not logical.. if you are using a 600 grit stone, there are deep scratches and you can use that stone all day and the scratches will remain. 600 grit stones will never produce a .3 micron finish.

so if you put a knife in the vice for the first time , chances are the edge is course

sorry for the typos.. originally posted.

Bill…

[cbwx34]

Should’ve said “the scratches from the previous stone are all gone.”.

But if you mark an edge with a Sharpie, then swipe it with a stone, you’re right, it will leave “high and low points” but there won’t be any Sharpie left… it doesn’t leave a low point with Sharpie inside.

And if you have an edge that is coarse and mark it with a Sharpie, then sharpen it with a fine stone, and don’t remove the coarse grind, then the edge isn’t sharpened to the level of the fine stone.  So if you have coarse grind (and Sharpie) left,then you’re not done at that level.  (What I meant before).

But mainly the Sharpie is primarily used just to see where the stone is hitting or not hitting… for example a microbevel that isn’t getting sharpened out or the stone’s path on an edge.  Not sure how Sharpie in the low points plays a part, other than what I described.

[Anonymous]

OK, I don’t really see this question asked , or a discussion on this.  ” Feel ”

I have reverted to the sensory perception of sharpness by ” Feel ” or ” Touch ”

When I’ve profiled a knife for a specific purpose ( set the angle of sharpness that I want ) . I go through the progressions of making a burr, and then go through the stones, using no water mist. After the ceramics, I’ve cut two pieces of #2000 grit wet-n-dry sand paper taped them to the ceramic stone set. I experimented at first with wetting them. it seemed to work well, but the second knife I did yesterday I used the sand paper dry… I like it better dry.  the amazing thing that I have learned is that a single stroke on one side can draw the edge to such a wicked sharp condition, I would not know it to be that sharp unless I actually felt it. I’ve discovered that a 10* degree angle can be effected dramatically by just one stroke in the wrong direction or side. The only way I know this is by feel. I have no scientific means to measure sharpness. I can view the edge with my microscope, but I can not tell if its truly sharp. when I view a single destructive view to the edge, by feel, and then look at it through the microscope, I can not see that very slight deflection.

My point is that I can tell by feel, if the edge is sharp, I can also tell if the edge is sharp from heel to tip. I’ve found ” By Feel” that  the heel and the tip have some deflection which translates into a less sharp section, which needs specific work . This is all by feel.

I use a piece of legal paper to test the sharpness, and when I’m done, I can select any section of my blade ( tip to heel ) and it slices through this paper like butter.

So I’m using ” feel ” to determine sharpness, and in my experiments, I find that a single stroke in the wrong direction, or on the wrong side of the edge will  effect the sharpness, dramatically.

So how is everyone determining sharpness…? Is ” Feel ” a part of your process?

[cbwx34]

How exactly are you “feeling” it?  Running your fingers along the edge (like Murray Carter’s 3-finger test), dragging a thumb across the edge… etc., and what result do you look for?
To answer your question, yes I feel an edge to check progress… testing it like the 3 finger test. Here’s it described, if you haven’t seen it…

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CliffCurry

[CliffCurry]

Anonymous wrote:

So how is everyone determining sharpness…? Is ” Feel ” a part of your process?

Im running out of arm hair ATM so my fallback has been push cutting phonebook paper because its thin.  I watched a video last night where a guy did a sharpening test that was almost like a magic trick 

 

[Anonymous]

Ok, I would never do that method again. Thanks for the video but I did exactly that the first time I sharpened a knife using the WEPS. AS attested and photographed, I cut my finger significantly, blood was everywhere, and I only use the lightest touch .This would be like drawing you finger along the edge of a razor…. my knife was so sharp I did know I was cut until I saw the blood gush out.

How I do it is exactly how he says not to do it.. dragging three fingers across the edge tells me if the edge is angular to one side, and also gives me a sense of sharpness, it also tells me which side of the knife increase the sharpness. … The feed back I get doing it the wrong way as oppose to dragging my fingers up and down the edge is very curious.. I would no more do that then drag my finders along the edge of a razor blade, in the manner in which he says his thumb is the safety device.

[cbwx34]

I don’t think what you’re doing is wrong… from your description it sounds like the way to primarily check for a burr.  I’m sure if you use it regularly, you can tell other things too.  Nothing wrong with that.

Not really a “feel” method,  but another way to test sharpness (and keep fingers safe) is with an “edge tester”…

Bob from Oldawan Tools sells it.  Once you get the hang of one, you can tell pretty accurately how sharp your knife is, if there’s any burrs, etc.  Here’s the link:

http://www.oldawan.com/sharpen/edge-tester/

something to consider.  (You can do some of the tests with a plastic pen… this just provides a little more accuracy and consistency).

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[Frans]

 

Im running out of arm hair ATM so my fallback has been push cutting phonebook paper because its thin. I watched a video last night where a guy did a sharpening test that was almost like a magic trick  

I sometimes test my knives like that but than with cigarette paper.

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CliffCurry

[Anonymous]

Thanks for the link to the pen device, but I have a micro scope I use to see any chips or toothiness.

Like I’ve posted before.. toothy edge @ 50X.

No so toothy

 

[cbwx34]

I thought we were talking about feeling an edge and testing for sharpness.  Can’t tell that with a scope (just a couple of posts up)…

Anonymous wrote:

I have no scientific means to measure sharpness. I can view the edge with my microscope, but I can not tell if its truly sharp. when I view a single destructive view to the edge, by feel, and then look at it through the microscope, I can not see that very slight deflection. My point is that I can tell by feel, if the edge is sharp, I can also tell if the edge is sharp from heel to tip.

So….???

[Anonymous]

The scope only shows nicks in the edge and level of polish in the bevel.. I can remove all the nicks in an edge and it still be very dull.  I can make a wickedly sharp edge dull with just one stroke., and it still look good on the scope. The scope is a visual reverence and not a scientific reference.  There is software out there that can measure the sharpness. there are scopes out there that can do that too… My edges are so straight and sharp now, that I am extremely happy with my results, and how I know this is true, is that I can repeat the process.  I’m also learning the terminal discipline of slicing through something with little to no impact on the edge. I’m talking 10* degree kitchen knives, not 18*degree or 20* degree utility  knives like my EDC;s.

[Anonymous]

I’m not trying to show what is best for others, I’m only showing my evolution of what is working for me over the last 2 months. I’m  also not putting anyone down for their process. Other people have help me to get to where I am now… like flying an airplane, its little correction , not big ones that get you to your final destination. sometimes the corrections are good and sometime they are no as good.

[CliffCurry]

Im gonna start a new Topic regarding testing for sharpness…if nothing else it will show some neat new tricks to try!  

[tcmeyer]

The best test I’ve found is inspection with the USB ‘scope.  I look directly down on the edge and focus on the apex, then slowly move from heel to tip.  A truly sharp edge will reflect no light.  Even the smallest burr will show up as a glint along the edge.  If the edge looks good at 50X and I really want the sharpest edge possible, I will go to 180X and reinspect the full length again.  Of course, each blade get the paper slicing test before sending it home.

I will also inspect for a centered apex by holding the ‘scope dead vertical and watching for differences in the width of the bevels.  If it looks wrong, I’ll roll the ‘scope from side to side to get a better view.

BTW, I often use the ‘scope as a measuring tool by capturing an image and measuring features with the software.  For instance, my wife has a very expensive wrist watch and one of the very small pins attaching the band to the watch fell out and disappeared.  With the ‘scope I measured the hole diameter and found it to be 1.511 mm.  Figured that the 11 microns was probably measuring error and ordered some 1.5mm rods on Amazon, saving about $90 in repair costs.

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