Community Sharpening Journal, Part 2

[vivi]

5 years ago.


@mage7

Sweet! I've been wondering about that for a long time. Thanks for confirmation.

Yes they were and yes it matters. Anyone who is sharpening by hand for edge retention testing is only doing a test of the randomness of their sharpening.

Again, thanks for confirmation that they were measured with a goniometer

I suppose my real question is how much it matter though.

Applying the regression formula you developed to Rex45 (2.5% MC and 5.3% M6C) and assuming it's 66 HRC, I get the following TCC estimates:

-157 + 15.8*66 – 17.8*30 + 26.2*2.5 + 9.5*5.3 = 467.65

-157 + 15.8*66 – 17.8*50 + 26.2*2.5 + 9.5*5.3 = 111.65

There's a huge decrease in edge retention going from 30 degrees to 50 degrees, but is it optimistic to assume that the decrease wouldn't be as bad if the 50 degree edge in question is formed by extremely small micro-bevels on top of a 30 degree edge?

I'm wondering if that's even something that can be speculated on, or if it would require actual testing to see. If the latter, have you ever thought about doing another set of CATRA tests with micro-bevels?

Do a rudimentary test.

Set up a scale on a cutting board and test the weight needed to cut various media with your two different conditions.

In my experience, microbevel performance behaves more like the geometry at the microbevel rather than the back bevel.

This is undesirable, like pre-dulling; reduced bite and cutting longevity.

Hmm so basically I should be able to see that the 30->50 degree bevel takes more force than the 30 degree bevel?

I do have a BESS tester, though it's one of the prototypes and is kind of inconsistent and so I question how accurate it is. I usually have to take like a five-point average. But in either case I can usually get between 75-100 BESS even on edges that I measure to be over 25dps.

Do you think using something like a simple kitchen scale and just observing the force to slice through something would be more revealing than the BESS tester? Wondering if that would show the force needed to pass the whole bevel through the test material versus just testing the apex against the BESS media.

As a slight aside, I've been planning on getting a new BESS tester and saving up cardboard to plot BESS scores over an amount of slices of a controlled length. I noticed in your video that you seemed to give it plenty of time for the CATRA blade to sever the media, whereas I see a lot of people kind of game the tester by doing the downward force quite quickly. Do you think it would be a better idea to buy one of the models that samples several times a second to eliminate that as a variable, or just get the basic model and try to go slowly?

I've tried both a home made BESS style tester (V notched block of wood with small nails on either side and thread looped over the notch) and kitchen scales.

In my experience the former is better for measuring raw apex sharpness, while the latter is better for showing the differences between overall geometry.

I was able to cut carrots and apples with 1/4 the force with a stock Pacific Salt VS a reprofiled edge bevel one, for example.

The difference is even more dramatic if you thin the full primary grind and not just the bevel, as shawn has always pointed out in the past.

[Mage7]

5 years ago.


@mage7

Sweet! I've been wondering about that for a long time. Thanks for confirmation.

It also makes me wonder about @Larrin 's CATRA tests. As far as I know the test coupons were sharpened with guided sharpeners, but I wonder if the angle at the apexes were verified with goniometers. Plus I kind of wonder if it even matters much. If there's a test blade whose even is ground at 30 degrees, but there's a bevel that's maybe .0005" wide at the very apex that is at 40 degrees, how much does it actually affect the data obtained?

Yes they were and yes it matters. Anyone who is sharpening by hand for edge retention testing is only doing a test of the randomness of their sharpening.

Again, thanks for confirmation that they were measured with a goniometer

I suppose my real question is how much it matter though.

Applying the regression formula you developed to Rex45 (2.5% MC and 5.3% M6C) and assuming it's 66 HRC, I get the following TCC estimates:

-157 + 15.8*66 – 17.8*30 + 26.2*2.5 + 9.5*5.3 = 467.65

-157 + 15.8*66 – 17.8*50 + 26.2*2.5 + 9.5*5.3 = 111.65

There's a huge decrease in edge retention going from 30 degrees to 50 degrees, but is it optimistic to assume that the decrease wouldn't be as bad if the 50 degree edge in question is formed by extremely small micro-bevels on top of a 30 degree edge?

I'm wondering if that's even something that can be speculated on, or if it would require actual testing to see. If the latter, have you ever thought about doing another set of CATRA tests with micro-bevels?

Do a rudimentary test.

Set up a scale on a cutting board and test the weight needed to cut various media with your two different conditions.

In my experience, microbevel performance behaves more like the geometry at the microbevel rather than the back bevel.

This is undesirable, like pre-dulling; reduced bite and cutting longevity.

Here's an idea for a test using Q-tips with the heads cut off. They're a plastic variety with a hollow center, and when they're cut they shoot off in either direction so it makes a pretty clear indication of the moment they're entirely severed. Their diameter is also no larger than the height of my edge bevel, and they compress, so it isolates the forces being measured to the blade grind.

This way I can also record it and measure the readout the very moment that the Q-tip's handle is completely split.

Also, a pretty good unintended example of the convexity of free-handed bevels going on with this one. Usually I hold a bit steadier in terms of going lower than my intended angle, but I was focusing on not trying to overshoot the apex too much this time. But it's a good example of how an edge that looks like it's about 10dps by the bevel height is just fairly convexed and is actually >=15dps.

I tested one edge and can see both sides are primarily 15dps, but there's the faintest little hint of the reflection from the 15-17 lines on one side, and from 15-16 on the other. But it's those faint lines that micro-bevels form so I know that's the true geometry and not just aberrant diffusion/scatter of the beam. Especially because they appear like that from the intended micro-bevels too.

Here you can see where the micro bevels start at the 15 degree lines. On one side it goes from 15-26 and the other 15-24. I used a 20 degree wedge so 20 + ~2.5 (for the blade grind) should have been 22.5, but I over-shot by 1.5 and 3.5 degrees respectively. It's a lot harder to nail the desired angle within +/- 2 degrees on a tiny little micro-bevel than on a huge bevel where I am putting most of the deviation into the shoulder.

I'm calling it a 33 degree apex vs a 50 degree apex, but not sure how valuable the numbers I would get with this would even be so I only did 3 cuts each for now. No sense in doing a lot more if my whole test methodology needs revision.

Unintended 33 degree apex on an intended 30 degree edge:
1st cut: 1.490kg
2nd cut: 1.183kg
3rd cur: 1.474kg
Avg: 1.382kg

Intended 50 degree micro-bevel apex on an intended 30 degree edge:
1st cut:1.461kg
2nd cut: 1.750kg
3rd cut: 1.675kg
Avg: 1.629kg

The average force increase necessary for the 50 degree micro-bevel is .247kg. Out of a maximum value of 1.750kg and a total spread of .567kg. That 1.183kg value might be an outlier, but even if I adjusted it up to 1.483kg to be more consistent with the full set, that would still be a .147kg increase in the average force over a spread of .288kg. With an average force of 1.55kg (regardless of that outlier) over either set of data, then the increase in average force over both sets is about 9.4% of the total average force to cut the Q-tip with either geometry.

What do you think of such a test and assessment of the values?

Also just for extra illustration purposes this is the micro-bevel in question. It looks larger in the picture than under a loupe somehow. Especially near the heel. The marker is where I am testing the geometry and cutting.

I've tried both a home made BESS style tester (V notched block of wood with small nails on either side and thread looped over the notch) and kitchen scales.

In my experience the former is better for measuring raw apex sharpness, while the latter is better for showing the differences between overall geometry.

I was able to cut carrots and apples with 1/4 the force with a stock Pacific Salt VS a reprofiled edge bevel one, for example.

The difference is even more dramatic if you thin the full primary grind and not just the bevel, as shawn has always pointed out in the past.

Yeah, I was trying to find something to test the whole bevel instead of just the apex, but also not the primary blade grind. However I'm thinking that removing the blade grind from the test probably makes the difference harder to observe as you say.

I'm trying to think of a different tear medium to test both the bevel and blade. Not sure about carrots, they seem like they'd be kind of inconsistent? I was thinking about just the standard rope, though perhaps nylon instead of a natural fiber. Otherwise I was also thinking about pencil erasers or something like that. Something that would really engage the blade surface and put friction into the equation to see if that amplifies the observable effect of differences are the edge.

[Deadboxhero]

Strong work.

Excellent creativity, a rudimentary test that can show differences between conditions with house hold items
@sal this is what we need.

We'll call it the "Mage" Test.




Yes, we see scatter but it could be smoothed out with more tests. 3 tests is the absolute bare minimum for us to see separation between the conditions I would recommend at least 5 in the future.

Especially if dealing with conditions that may have an unknown outcome or counter intuitive behavior.


If the objective was to quantify the difference better that would benefit from more control ( jig sharpening, test fixtures, etc) which would result in more distinct, cleaner data.

The testing shows the behavior that a traditional microbevel with thicker angles at the apex takes more force to cut with than no microbevel.

Hence, why I don't enjoy or use them (as previously shared)



The test is simple enough for others to replicate to compare other behaviors as well.

Mage, well done.

If the edge is a ghost, you are definitely a "Ghostbuster"

5 years ago.


@mage7

Sweet! I've been wondering about that for a long time. Thanks for confirmation.

Yes they were and yes it matters. Anyone who is sharpening by hand for edge retention testing is only doing a test of the randomness of their sharpening.

Again, thanks for confirmation that they were measured with a goniometer

I suppose my real question is how much it matter though.

Applying the regression formula you developed to Rex45 (2.5% MC and 5.3% M6C) and assuming it's 66 HRC, I get the following TCC estimates:

-157 + 15.8*66 – 17.8*30 + 26.2*2.5 + 9.5*5.3 = 467.65

-157 + 15.8*66 – 17.8*50 + 26.2*2.5 + 9.5*5.3 = 111.65

There's a huge decrease in edge retention going from 30 degrees to 50 degrees, but is it optimistic to assume that the decrease wouldn't be as bad if the 50 degree edge in question is formed by extremely small micro-bevels on top of a 30 degree edge?

I'm wondering if that's even something that can be speculated on, or if it would require actual testing to see. If the latter, have you ever thought about doing another set of CATRA tests with micro-bevels?

Do a rudimentary test.

Set up a scale on a cutting board and test the weight needed to cut various media with your two different conditions.

In my experience, microbevel performance behaves more like the geometry at the microbevel rather than the back bevel.

This is undesirable, like pre-dulling; reduced bite and cutting longevity.

Here's an idea for a test using Q-tips with the heads cut off. They're a plastic variety with a hollow center, and when they're cut they shoot off in either direction so it makes a pretty clear indication of the moment they're entirely severed. Their diameter is also no larger than the height of my edge bevel, and they compress, so it isolates the forces being measured to the blade grind.

This way I can also record it and measure the readout the very moment that the Q-tip's handle is completely split.

Screenshot_20250818-124748~2.png
Screenshot_20250818-124807~2.png


Also, a pretty good unintended example of the convexity of free-handed bevels going on with this one. Usually I hold a bit steadier in terms of going lower than my intended angle, but I was focusing on not trying to overshoot the apex too much this time. But it's a good example of how an edge that looks like it's about 10dps by the bevel height is just fairly convexed and is actually >=15dps.

I tested one edge and can see both sides are primarily 15dps, but there's the faintest little hint of the reflection from the 15-17 lines on one side, and from 15-16 on the other. But it's those faint lines that micro-bevels form so I know that's the true geometry and not just aberrant diffusion/scatter of the beam. Especially because they appear like that from the intended micro-bevels too.


PXL_20250818_015100607~2.jpg


Here you can see where the micro bevels start at the 15 degree lines. On one side it goes from 15-26 and the other 15-24. I used a 20 degree wedge so 20 + ~2.5 (for the blade grind) should have been 22.5, but I over-shot by 1.5 and 3.5 degrees respectively. It's a lot harder to nail the desired angle within +/- 2 degrees on a tiny little micro-bevel than on a huge bevel where I am putting most of the deviation into the shoulder.


PXL_20250818_073818579~3.jpg
PXL_20250818_073823661~3.jpg


I'm calling it a 33 degree apex vs a 50 degree apex, but not sure how valuable the numbers I would get with this would even be so I only did 3 cuts each for now. No sense in doing a lot more if my whole test methodology needs revision.

Unintended 33 degree apex on an intended 30 degree edge:
1st cut: 1.490kg
2nd cut: 1.183kg
3rd cur: 1.474kg
Avg: 1.382kg

Intended 50 degree micro-bevel apex on an intended 30 degree edge:
1st cut:1.461kg
2nd cut: 1.750kg
3rd cut: 1.675kg
Avg: 1.629kg

The average force increase necessary for the 50 degree micro-bevel is .247kg. Out of a maximum value of 1.750kg and a total spread of .567kg. That 1.183kg value might be an outlier, but even if I adjusted it up to 1.483kg to be more consistent with the full set, that would still be a .147kg increase in the average force over a spread of .288kg. With an average force of 1.55kg (regardless of that outlier) over either set of data, then the increase in average force over both sets is about 9.4% of the total average force to cut the Q-tip with either geometry.

What do you think of such a test and assessment of the values?

Also just for extra illustration purposes this is the micro-bevel in question. It looks larger in the picture than under a loupe somehow. Especially near the heel. The marker is where I am testing the geometry and cutting.


PXL_20250818_074550196~2.jpg
PXL_20250818_074610651~2.jpg

I've tried both a home made BESS style tester (V notched block of wood with small nails on either side and thread looped over the notch) and kitchen scales.

In my experience the former is better for measuring raw apex sharpness, while the latter is better for showing the differences between overall geometry.

I was able to cut carrots and apples with 1/4 the force with a stock Pacific Salt VS a reprofiled edge bevel one, for example.

The difference is even more dramatic if you thin the full primary grind and not just the bevel, as shawn has always pointed out in the past.

Yeah, I was trying to find something to test the whole bevel instead of just the apex, but also not the primary blade grind. However I'm thinking that removing the blade grind from the test probably makes the difference harder to observe as you say.

I'm trying to think of a different tear medium to test both the bevel and blade. Not sure about carrots, they seem like they'd be kind of inconsistent? I was thinking about just the standard rope, though perhaps nylon instead of a natural fiber. Otherwise I was also thinking about pencil erasers or something like that. Something that would really engage the blade surface and put friction into the equation to see if that amplifies the observable effect of differences are the edge.

[vivi]

to be fair 50dps microbevel is pretty extreme. I don't run an apex at that thick of an angle on my 28" chopping axe.

the performance differential would be a lot smaller with, say, a 32-35dps micro.

on a lot of knives they make a lot of sense to speed up sharpening time.

I use my knives on wood carving a lot, and applying microbevels the way I do (very close to the edge bevels angle) they don't have a perceptible performance effect. Knife still bites into wood at the same angle.

microbevels can allow for thinner behind the edge geometry too. say your edge starts to fail on edc tasks at 10dps but is stable at 12dps. give the edge an 8dps bevel, then micro at 12dps. higher performance than running a standard 12dps edge.

I like micros because I can refresh a knife's apex in about 20 seconds. tough to do that when sharpening a full bevel unless the entire primary grind has been thinned a lot. doing that requires a decent bit of skill on a belt sander, and can also ruin DLC finishes, which sacrifices corrosion resistance.

so micros are a good balance for me. cutting performance, extremely fast touch-ups, edge toughness, corrosion resistance....many factors at play.

[TkoK83Spy]

Nothing too crazy here. Just freehanding with the medium and fine stones, cleaning up the edge for feathersticks from kindling wood. I go through quite a process when I have firewood delivered, but I love having reason to use the maul, axe, machete and Mule!

[u.w.]

Put my own (bit thinner than factory) edge on this: The new all black ffg Police. It's a 300 grit edge done with the HF diamond, and deburred on a well worn 325 dmt coarse. The burr seemed a little stubborn, but it's only the first sharpening; and included a re-profile at that, so I'll see how it acts as time passes

[/url]

u.w.

[ejames13]

Put my own (bit thinner than factory) edge on this: The new all black ffg Police. It's a 300 grit edge done with the HF diamond, and deburred on a well worn 325 dmt coarse. The burr seemed a little stubborn, but it's only the first sharpening; and included a re-profile at that, so I'll see how it acts as time passes

[/url]

u.w.

How did you get all the way to the heel with that HF diamond? The plates on mine don't go all the way to the edges.

[u.w.]

Put my own (bit thinner than factory) edge on this: The new all black ffg Police. It's a 300 grit edge done with the HF diamond, and deburred on a well worn 325 dmt coarse. The burr seemed a little stubborn, but it's only the first sharpening; and included a re-profile at that, so I'll see how it acts as time passes

[/url]

u.w.

How did you get all the way to the heel with that HF diamond? The plates on mine don't go all the way to the edges.

You are absolutely right, as sold in, or on, the four sided block they will NOT go all the way to the heel.
For some that's ok.
I'm not on that list of folks though, so...

I put the cut-off wheel on my dremel and cut down each corner of the four sided block (you gotta pop off the sort of blue-ish teal-ish plastic end caps), end to end. What I ended up with was four separate pieces that had some melted plastic "fluff" and stuff along their long sides that was very, very easy to scrape off. Once I'd done that - that little plastic shelf was gone and I could sharpen all the way to the heel easily on each of the four pieces/grits.
Also made it easier to transport them, or just one or two of them, and puts my hand closer to the blade/edge when sharpening - all of which I prefer.
I wrote on the back of each piece what grit they were so I can/could always refer to that.
I will say also
Leave the plastic pieces on the stones/attached. They keep it straight, or a lot straight-er.

if ya got any more questions, please feel free to ask

u.w.

[vivi]

that police edge looks good!

I'm debating between ordering one of those or a blacked out S30V Manix XL next. Probably going to go with the police and be patient for the Manix XL Salt. I don't own any stainless scaled Police folders so tht'd be more unique in my collection anyways.

How's the grip compared to plain steel scaled spydies? In my experience the black coated ATR's etc. had slightly better grip than the plain finished ones. Hoping that's the case here.

Put my own (bit thinner than factory) edge on this: The new all black ffg Police. It's a 300 grit edge done with the HF diamond, and deburred on a well worn 325 dmt coarse. The burr seemed a little stubborn, but it's only the first sharpening; and included a re-profile at that, so I'll see how it acts as time passes

[/url]

u.w.

How did you get all the way to the heel with that HF diamond? The plates on mine don't go all the way to the edges.

If you angle the knife it's easy to get the heel ground down on those without modding the stone.

I have one where I pried the plates off and re-glued them closer to the right side edge, since I sharpen right handed.

If you want to get that area without modding the stone, try angling the knife so the tip is pointing down towards 7-8 o clock if you're looking down from above the stone (4-5 o cpock if you sharpen with the handle on the left side of the stone)

[vivi]

reset the edge on my m4 manix with a 140 grit diamond plate.

refined it on a dmt coarse plate until it caught hairs above the skin and popped arm hairs along the full length of the edge.

no microbevel, 10-12dps. should be a mean slicer.





millie 2 salt is next up

[vivi]

****, the first inch of edge rolled enough to reflect light from stabbing a tin of olive oil. Something I've done with this knife a hundred times with no damage.

microbevel going back on next time I sharpen.

[Mage7]

Strong work.

Excellent creativity, a rudimentary test that can show differences between conditions with house hold items
@sal this is what we need.

We'll call it the "Mage" Test.




Yes, we see scatter but it could be smoothed out with more tests. 3 tests is the absolute bare minimum for us to see separation between the conditions I would recommend at least 5 in the future.

Especially if dealing with conditions that may have an unknown outcome or counter intuitive behavior.


If the objective was to quantify the difference better that would benefit from more control ( jig sharpening, test fixtures, etc) which would result in more distinct, cleaner data.

The testing shows the behavior that a traditional microbevel with thicker angles at the apex takes more force to cut with than no microbevel.

Hence, why I don't enjoy or use them (as previously shared)



The test is simple enough for others to replicate to compare other behaviors as well.

Mage, well done.

If the edge is a ghost, you are definitely a "Ghostbuster"

Sweet! I've been wondering about that for a long time. Thanks for confirmation.



Again, thanks for confirmation that they were measured with a goniometer

I suppose my real question is how much it matter though.

Applying the regression formula you developed to Rex45 (2.5% MC and 5.3% M6C) and assuming it's 66 HRC, I get the following TCC estimates:

-157 + 15.8*66 – 17.8*30 + 26.2*2.5 + 9.5*5.3 = 467.65

-157 + 15.8*66 – 17.8*50 + 26.2*2.5 + 9.5*5.3 = 111.65

There's a huge decrease in edge retention going from 30 degrees to 50 degrees, but is it optimistic to assume that the decrease wouldn't be as bad if the 50 degree edge in question is formed by extremely small micro-bevels on top of a 30 degree edge?

I'm wondering if that's even something that can be speculated on, or if it would require actual testing to see. If the latter, have you ever thought about doing another set of CATRA tests with micro-bevels?

Do a rudimentary test.

Set up a scale on a cutting board and test the weight needed to cut various media with your two different conditions.

In my experience, microbevel performance behaves more like the geometry at the microbevel rather than the back bevel.

This is undesirable, like pre-dulling; reduced bite and cutting longevity.

Here's an idea for a test using Q-tips with the heads cut off. They're a plastic variety with a hollow center, and when they're cut they shoot off in either direction so it makes a pretty clear indication of the moment they're entirely severed. Their diameter is also no larger than the height of my edge bevel, and they compress, so it isolates the forces being measured to the blade grind.

This way I can also record it and measure the readout the very moment that the Q-tip's handle is completely split.

Screenshot_20250818-124748~2.png
Screenshot_20250818-124807~2.png


Also, a pretty good unintended example of the convexity of free-handed bevels going on with this one. Usually I hold a bit steadier in terms of going lower than my intended angle, but I was focusing on not trying to overshoot the apex too much this time. But it's a good example of how an edge that looks like it's about 10dps by the bevel height is just fairly convexed and is actually >=15dps.

I tested one edge and can see both sides are primarily 15dps, but there's the faintest little hint of the reflection from the 15-17 lines on one side, and from 15-16 on the other. But it's those faint lines that micro-bevels form so I know that's the true geometry and not just aberrant diffusion/scatter of the beam. Especially because they appear like that from the intended micro-bevels too.


PXL_20250818_015100607~2.jpg


Here you can see where the micro bevels start at the 15 degree lines. On one side it goes from 15-26 and the other 15-24. I used a 20 degree wedge so 20 + ~2.5 (for the blade grind) should have been 22.5, but I over-shot by 1.5 and 3.5 degrees respectively. It's a lot harder to nail the desired angle within +/- 2 degrees on a tiny little micro-bevel than on a huge bevel where I am putting most of the deviation into the shoulder.


PXL_20250818_073818579~3.jpg
PXL_20250818_073823661~3.jpg


I'm calling it a 33 degree apex vs a 50 degree apex, but not sure how valuable the numbers I would get with this would even be so I only did 3 cuts each for now. No sense in doing a lot more if my whole test methodology needs revision.

Unintended 33 degree apex on an intended 30 degree edge:
1st cut: 1.490kg
2nd cut: 1.183kg
3rd cur: 1.474kg
Avg: 1.382kg

Intended 50 degree micro-bevel apex on an intended 30 degree edge:
1st cut:1.461kg
2nd cut: 1.750kg
3rd cut: 1.675kg
Avg: 1.629kg

The average force increase necessary for the 50 degree micro-bevel is .247kg. Out of a maximum value of 1.750kg and a total spread of .567kg. That 1.183kg value might be an outlier, but even if I adjusted it up to 1.483kg to be more consistent with the full set, that would still be a .147kg increase in the average force over a spread of .288kg. With an average force of 1.55kg (regardless of that outlier) over either set of data, then the increase in average force over both sets is about 9.4% of the total average force to cut the Q-tip with either geometry.

What do you think of such a test and assessment of the values?

Also just for extra illustration purposes this is the micro-bevel in question. It looks larger in the picture than under a loupe somehow. Especially near the heel. The marker is where I am testing the geometry and cutting.


PXL_20250818_074550196~2.jpg
PXL_20250818_074610651~2.jpg

I've tried both a home made BESS style tester (V notched block of wood with small nails on either side and thread looped over the notch) and kitchen scales.

In my experience the former is better for measuring raw apex sharpness, while the latter is better for showing the differences between overall geometry.

I was able to cut carrots and apples with 1/4 the force with a stock Pacific Salt VS a reprofiled edge bevel one, for example.

The difference is even more dramatic if you thin the full primary grind and not just the bevel, as shawn has always pointed out in the past.

Yeah, I was trying to find something to test the whole bevel instead of just the apex, but also not the primary blade grind. However I'm thinking that removing the blade grind from the test probably makes the difference harder to observe as you say.

I'm trying to think of a different tear medium to test both the bevel and blade. Not sure about carrots, they seem like they'd be kind of inconsistent? I was thinking about just the standard rope, though perhaps nylon instead of a natural fiber. Otherwise I was also thinking about pencil erasers or something like that. Something that would really engage the blade surface and put friction into the equation to see if that amplifies the observable effect of differences are the edge.

Thanks!

I haven't been able to follow up with any more actual testing, but I have been thinking about things to test and how to further test them.

I was going over some of Larrin's older articles...

https://knifesteelnerds.com/2018/06/18/ ... retention/
https://knifesteelnerds.com/2018/08/06/ ... g-ability/

They had me wondering more about the relationship between the apex radius width and cutting ability. If I understand his conclusions correctly, edge angle controls cutting ability more than any other factor, and that an acute edge had greater cutting ability than an obtuse edge, even if the obtuse edge's apex remains narrower than the apex of the acute edge.

I am thinking about doing something like cutting up a ton of cardboard, and in specific intervals taking the BESS score and plotting that out. I have done that in the past, but I think this time around I could do it in conjunct with the Q tip test. Because I think that as in the articles, BESS is really going to be a factor of the apex radius width, but the force in the Q tip test will be a factor of both the apex radius as well as the rest of the edge geometry displacing the material.

I think the first obvious test I would run is to take a 30 degree bevel, run it through cardboard and plot both the BESS and Q-tip cut-force (I may be too modest to refer to it as the Mage score lol) and then do the same with a 30 degree bevel with a micro-bevel and see what differences shake out.

But I will need to get a new BESE tester. The one I have is one of those ancient prototype ones...

It's just far too temperamental. I always seem to get wildly different readings from one reading to the other, because there's just so much variation on tensioning the thread I think. I been wanting to get one of the new ones to use the clips with. Seems like it would be a lot more accurate and also not nearly as much of a hassle. Spooling up the thread, loading the weight, etc. gets really tedious when plotting it out over thousands of cuts.

It's pretty disappointing though seeing that their "home model" only has 25 gram resolution. I wonder what the max capacity is as well. It would be nice to be able to use it to measure the peak force on the Q tip test too.

to be fair 50dps microbevel is pretty extreme. I don't run an apex at that thick of an angle on my 28" chopping axe

the performance differential would be a lot smaller with, say, a 32-35dps micro.

Yeah I was aiming for closer to 45. But also at least the exaggerated difference helped show some amount of difference. Hard to really draw conclusions on the amount of measurements I took, but the amount of force increase wasn't really that much even with such a big bevel, so I think you're right. I plan to test micro-bevels with much less contrast to the main bevel.

so micros are a good balance for me. cutting performance, extremely fast touch-ups, edge toughness, corrosion resistance....many factors at play.

I am sort of just making this an academic pursuit to see if I can find a way to use micro-bevels in a way that reduces the increase of apex radius width when cutting through more obtuse geometry, but that doesn't reduce cutting ability are the same time. Because my intuition is telling me that the reasons why a more obtuse edge bevel would reduce cutting ability should reduce in proportion to the size of the bevel faces. Things like the friction and material displacement should be minimized the smaller the bevel faces are, but also allow the apex to preserve a narrower apex radius for longer. Basically the best of both worlds. Though, as Shawn was saying that he's observed micro-bevel edges basically acting like they would if they were a whole V bevel if that geometry so I may be overly optimistic, but my hopes are that extremely small micro-bevels will accomplish this.

Speaking of academic pursuit..

Can anyone explain these graphs from those articles to me?




It's said that, "A typical test for a plain edge steel knife is 60 cuts with 50N load at 50 mm/s," but what does the cut length and the 50 mm/s reference here? Is it the length and rate of the slicing stroke or the depth of the cut into the stack of cards?

If it's length of the stroke, how is that controlled? If you look at the line for the 20 degree edge beginning at cut 20 there's a pretty interesting fluctuation between 10 and 20 that would seem like it would rule out that it pertains to the length of the slice since that would mean the blade was basically being sawed back and forth in increasingly short strokes.

So then it must be the depth of the cut into the card stack, but then doesn't it just correspond to the TCC graph too since cards are 1mm?

Just wanting to make sure I am reading all that right.

[Brock O Lee]

Fresh 15 dps 1000 grit edges for the garage dwellers.

[vivi]

10 minute sharpening session with work knives / pizza cutters.





ran them on the sharpmaker medium rods 2-4 times per side afterwards. nice and toothy

[ncrockclimb]

I sharpened my favorite daily carry knife and put a new edge on my new Lil’ Native LW. As usual, I used my KME and Venev bonded diamond stones. Since the Lil’ Native was new, I set the bevel to 12 dps with an F80. I keep almost all my knives at this angle so sharpening is quick and easy. I then finished both knives with a relatively course F150.

For me, this is the ideal edge. It has teeth and will chew thru course material, but will still shave and quietly slice phone book paper. The key to this edge is making sure that there is no burr and that the edge is consistently apexed. I spend a lot of time with alternating light, edge forward passes on the stone and using a dowel to fold the burr up and make sure it is removed.

As always, i love seeing all the cool sharpening jobs all of you do. I’ll be posting up again soon with my new 15V Native 5 LW.

[TkoK83Spy]

12 dps, I like it. Looking good!

[ncrockclimb]

12 dps, I like it. Looking good!

Thanks! I would probably go even lower, but the KME won't do it.

[vivi]

free hand will

sounds like a good edge. I use similar ones. 10-12dps,coarse finish, very light edge leading strokes to minimize the burr so despite the low grit finish they shave just fine.

I find these edges last much longer than the thicker, more polished edges most folks run.

[ncrockclimb]

free hand will

sounds like a good edge. I use similar ones. 10-12dps,coarse finish, very light edge leading strokes to minimize the burr so despite the low grit finish they shave just fine.

I find these edges last much longer than the thicker, more polished edges most folks run.

you influenced me to start sharpening this way. thank you!

[Guts]

Honed my Lil Temp 3 in K390 on a Naniwa 400gr resin bonded diamond stone, then a couple passes on ~1um tech diamond tools paste on leather. It's back to slicing free hanging paper towel