The low grit sharpening thread

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Brock O Lee
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Re: The low grit sharpening thread

#101

Post by Brock O Lee »

Something I really like about coarse edges, is that I do not nick myself as often as with polished edges.

I think it is because coarse edges do not push cut as well as polished edges, which tend to split skin at the lightest contact.
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Re: The low grit sharpening thread

#102

Post by FK »

Brock O Lee wrote:
Fri Jul 09, 2021 3:12 am
Something I really like about coarse edges, is that I do not nick myself as often as with polished edges.

I think it is because coarse edges do not push cut as well as polished edges, which tend to split skin at the lightest contact.
I beleive it is because polished edges are very sharp,,,, coarse edges have rather thick ragged apex. We all agree the polished edge push cuts much better wrt coarse edge.
Most arm hair cutting demos with coarse edges are really scraping the hair off in clumps,,, not "tree topping" classic cutting.
I do like coarse edges for slicing cuts in hard plastics and some tough slippery material.

Solution,,,,, carry two knives,,,,,, Delica with polished fine apex and Endura with polished main bevel and micro bevel with rather coarse final apex.

Regards.
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Re: The low grit sharpening thread

#103

Post by u.w. »

vivi wrote:
Tue Jul 06, 2021 11:11 am
....
I'm not the most educated on scratch patterns to be honest.

I do know the scratch pattern influences slicing. If you look at this edge, for example:

Image

You'll see the pattern is diagonal, kind of like it's going from the top of the tip to the bottom of the heel.

Now if I take this knife and slice straight down into cardboard, I notice something.

Slicing going from tip to heel is more efficient than slicing from heel to tip, all else being equal.

So if you prefer slicing from heel to tip like most do, my experience tells me you'd have a more effective edge sharpening tip to heel rather than heel to tip.
That makes sense, and makes me wonder,

Does cutting with or against the scratch pattern, have an effect on how long the edge lasts?
And where would a perpendicular to edge scratch pattern fall out?

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Re: The low grit sharpening thread

#104

Post by FK »

This theory has been discussed for many years. The primary bevel scratch pattern or direction relating to the slicing cut has no effect on the apex wear. The actual apex is what is accomplishing the cutting and is a variable with angle, thickness of apex, finish, material cut, direction of cut and other factors.
You may observe a friction component from coarse bevel finish and feedback feeling from direction of cut through cardboard. This is why I like a polished bevel with coarse micro bevel for some materials.
The apex is not a serrated edge like we see in Spyderco SE or bread knives, it is a rough ragged peaks and valleys which is normally only illustrated in two dimensions in photos. We rarely see the width of the apex, I believe this is an important consideration for sharpness. Some articles state a very sharp edge should be 1-2 microns in thickness for consideration.

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Re: The low grit sharpening thread

#105

Post by u.w. »

Interesting.

And, agreed that the width of the edge relates to how sharp. I can't imagine you'd find anyone who'd disagree.

I'd not say a low grit edge finish is "sharper" (narrower apex width) than a high grit edge finish.

I'm saying, a low grit edge finish works better for me, for a lot of what I use my knife(s) for, than a high grit edge finish does.
For a lot of the stuff I cut, I find I prefer the "ragged" apex of the low grit sharpened edge. For me, in most of my uses, it just works so much better, and faster.


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Re: The low grit sharpening thread

#106

Post by soc_monki »

I've found that sharpening on a 220 grit dmt extra coarse, then refining the edge with a Spyderco Medium, gets me results that I like. Once I have touched the edge up so much that the scratch pattern is practically nonexistant I use the 220 grit again and repeat. Makes for a very grabby edge that can tree top hair as well. It works for me. Sometimes certain knives like different finishes, so I may do a 320 grit finish, or 1200 diamond, or go all the way to Spyderco Fine. It's nice to have variety! Overall though, if I was limited to 2 stones, it would be a 220 or 320 diamond, and the Spydie Medium.
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Re: The low grit sharpening thread

#107

Post by skeeg11 »

Nice to have options depending upon use, but a polished bevel with a 220 grit micro is my most often used MO.
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Re: The low grit sharpening thread

#108

Post by vivi »

u.w. wrote:
Sat Jul 10, 2021 8:55 am
Interesting.

And, agreed that the width of the edge relates to how sharp. I can't imagine you'd find anyone who'd disagree.

I'd not say a low grit edge finish is "sharper" (narrower apex width) than a high grit edge finish.

I'm saying, a low grit edge finish works better for me, for a lot of what I use my knife(s) for, than a high grit edge finish does.
For a lot of the stuff I cut, I find I prefer the "ragged" apex of the low grit sharpened edge. For me, in most of my uses, it just works so much better, and faster.


Respectfully,
u.w.
The raggedness of the apex means as it dulls there are still peaks and valleys forming micro serrations. High polish apexes get smooth and glassy after being dulled, and there is a dramatic drop in cutting ability when going from freshly sharpened to 80% sharp.

So it doesn't just change how they cut, but how long they cut. In the same way a dull serrated knife will still be able to cut things, a dull low grit plain edge knife will remain useful weeks after losing shaving ability.

I haven't sharpened my EDC since I cut up that cardboard then made the sharpening video. It doesn't shave anymore because I've used it a good bit. It still cuts fine though, no need to sharpen it.

On the other hand I wouldn't walk out the door carrying a high polish PE knife that's so dull it can't scrape shave. Cutting performance would be too poor.
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Re: The low grit sharpening thread

#109

Post by u.w. »

I'm with ya vivi.
My comment, or post, was toward FK's posts stating that a coarser, or low grit, edge wasn't as sharp as a finer one, and was ragged by comparison.
And I wasn't disagreeing with FK, just stating that the "ragged" and "less sharp" (comparatively) edge worked better for me, for the vast majority of how and what I use my knives for.

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Re: The low grit sharpening thread

#110

Post by S-3 ranch »

Science of sharp duel edge
https://scienceofsharp.com/2021/06/15/d ... harpening/

If you have the sharpening equipment and skills it’s a awesome way to sharpen a blade :spyder:
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Re: The low grit sharpening thread

#111

Post by u.w. »

Do you sharpen and use your blade edges that way S-3 ranch?

Have you just sharpened and used 200 or 300 grit edges? and Have you just sharpened and used hi-grit edges, say 10,000 grit and above.

And did you notice better performance out of the "combo" edge as opposed to the low grit and/or high grit?

Or are you just sharing their posts & videos so we can see them? My intended tone in typing this is friendly & inquisitive, not offensive and challenging.

u.w.
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Re: The low grit sharpening thread

#112

Post by jpm2 »

S-3 ranch wrote:
Sat Jul 10, 2021 2:34 pm
Science of sharp duel edge
https://scienceofsharp.com/2021/06/15/d ... harpening/

If you have the sharpening equipment and skills it’s a awesome way to sharpen a blade :spyder:
What if you used a diamond rod on one side of the sharpmaker and fine ceramic on the other side?
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Re: The low grit sharpening thread

#113

Post by S-3 ranch »

u.w. wrote:
Sat Jul 10, 2021 3:05 pm
Do you sharpen and use your blade edges that way S-3 ranch?

Have you just sharpened and used 200 or 300 grit edges? and Have you just sharpened and used hi-grit edges, say 10,000 grit and above.

And did you notice better performance out of the "combo" edge as opposed to the low grit and/or high grit?

Or are you just sharing their posts & videos so we can see them? My intended tone in typing this is friendly & inquisitive, not offensive and challenging.

u.w.
Yes , I have sharpen my knives with the duel edge, it does stretch out the length of time between sharpening,
I really don’t think using a sharp maker with different types rods will make it
My usual process is
400 diamond
Then a series of strops down to 1 micron diamond and finish with bare leather
“”Think of an edge as a living thing that comes and goes, born, get's old, is reborn.””
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Re: The low grit sharpening thread

#114

Post by u.w. »

S-3 ranch wrote:
Sat Jul 10, 2021 2:34 pm
Science of sharp duel edge
https://scienceofsharp.com/2021/06/15/d ... harpening/

If you have the sharpening equipment and skills it’s a awesome way to sharpen a blade :spyder:

A member & poster here, Tom Hosang, did some testing using a relatively hi-grit edge, the "dual grit sharpening", and a low-grit edge.

Tom, I hope you don't mind me posting up your video here. I think it's a great video, with interesting results, and backs up why I went to low grit edges some time ago now.

Thanks for taking the time to do all that testing, video it, and sharing it

Tom's video:





I also find it interesting that the knife he did his testing with has CPM-S30V steel, and not a "basic", or, "simple" or, "soft" steel...

u.w. wrote: In reference to the "dual-grit edge": Do you sharpen and use your blade edges that way?

Have you just sharpened and used 200 or 300 grit edges? and Have you just sharpened and used hi-grit edges, say 10,000 grit and above.

And did you notice better performance out of the "combo" edge as opposed to the low grit and/or high grit?

u.w.

He basically does answer the questions I'd asked, and at least with his knife, that he sharpened, and his cutting - the low grit edge did indeed outperform Both the "dual-grit" edge, and the "hi-grit" edge.

He's not the only one either...

u.w.
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Re: The low grit sharpening thread

#115

Post by TkoK83Spy »

Over the past 6 months or so of sharpening/reprofiling any knife I've used at no more than 600 grit (typically anywhere from 200-320)...I can totally agree with that.

Can't beat a working edge that last longer, and takes A LOT less time than getting all fancy with a mirror finish. Seems pointless to me unless it's just for show...which anybody can shine up an edge to just sit around in a safe or on display. I just don't like mirror finishes...they remind me of someone that has a classic muscle car, but never drives it and trailers it to car shows.
15 :bug-red 's in 10 different steels
1 - Bradford Guardian 3 / Vanadis 4E Wharnie
1 - Monterey Bay Knives Slayback Flipper / ZDP 189
1 - CRK Small Sebenza 31/Macassar Ebony Inlays
1 - CRK Large Inkosi Insingo/ Black Micarta Inlays
1 - CRK Small Sebenza 31 Insingo/Magnacut

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Re: The low grit sharpening thread

#116

Post by vivi »

TkoK83Spy wrote:
Fri Sep 17, 2021 8:03 pm
Over the past 6 months or so of sharpening/reprofiling any knife I've used at no more than 600 grit (typically anywhere from 200-320)...I can totally agree with that.

Can't beat a working edge that last longer, and takes A LOT less time than getting all fancy with a mirror finish. Seems pointless to me unless it's just for show...which anybody can shine up an edge to just sit around in a safe or on display. I just don't like mirror finishes...they remind me of someone that has a classic muscle car, but never drives it and trailers it to car shows.
Yep. I keep a few knives polished just to carry something different at times, but you can't beat the longevity of a coarse edge.

By going from the sharpmaker medium rods to my 200 grit harbor freight diamond stone I can go about 4x as long between touch-ups, if not longer.

I've gotten to the point where I feel underknifed if all I have is a polished edge on me.
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Re: The low grit sharpening thread

#117

Post by TkoK83Spy »

I have one of my CRK's with a fairly polished edge I work on from time to time, but know I won't be using much...at least at work with all the abrasive and nasty stuff I can get into.

Since going right off of low grit diamond or CBN abrasives, it honestly makes me chuckle when I hear people going "coarse" with the medium rods. Might as well call those ultra fine!

I'm sure there are certain applications where a mirror finish is more beneficial, but in my line of work and knife use, it's always underperformed. I also like the look of a bevel that I can see the scratch pattern. Starting to convert one of my buddies at work after I sharpened his XHP Shaman to 320 grit. He thought that was against the rules until I convinced him to try it for a week.
15 :bug-red 's in 10 different steels
1 - Bradford Guardian 3 / Vanadis 4E Wharnie
1 - Monterey Bay Knives Slayback Flipper / ZDP 189
1 - CRK Small Sebenza 31/Macassar Ebony Inlays
1 - CRK Large Inkosi Insingo/ Black Micarta Inlays
1 - CRK Small Sebenza 31 Insingo/Magnacut

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Re: The low grit sharpening thread

#118

Post by vivi »

TkoK83Spy wrote:
Fri Sep 17, 2021 8:35 pm
I have one of my CRK's with a fairly polished edge I work on from time to time, but know I won't be using much...at least at work with all the abrasive and nasty stuff I can get into.

Since going right off of low grit diamond or CBN abrasives, it honestly makes me chuckle when I hear people going "coarse" with the medium rods. Might as well call those ultra fine!

I'm sure there are certain applications where a mirror finish is more beneficial, but in my line of work and knife use, it's always underperformed. I also like the look of a bevel that I can see the scratch pattern. Starting to convert one of my buddies at work after I sharpened his XHP Shaman to 320 grit. He thought that was against the rules until I convinced him to try it for a week.
I have zero doubts more people would feel this way if they used a mirror edge and a ~200-400 grit edge side by side.

I don't know about you, but with a utility EDC I do more slicing than push cutting.

That feeling of slicing with a polished edge and not feeling it bite any better as I slide the apex across the material I'm cutting - I've come to hate that feeling. It feels backwards to how a knife should work to me.
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Re: The low grit sharpening thread

#119

Post by TkoK83Spy »

Totally agree, that bite and even a bit of sound difference with the coarse edge is a bit more enjoyable in my eyes/ears. Then again, I also love me some death metal, so noise is kind of my thing!

I actually forgot all about this thread, glad to see it revived tonight!
15 :bug-red 's in 10 different steels
1 - Bradford Guardian 3 / Vanadis 4E Wharnie
1 - Monterey Bay Knives Slayback Flipper / ZDP 189
1 - CRK Small Sebenza 31/Macassar Ebony Inlays
1 - CRK Large Inkosi Insingo/ Black Micarta Inlays
1 - CRK Small Sebenza 31 Insingo/Magnacut

-Rick
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Re: The low grit sharpening thread

#120

Post by soc_monki »

I still flip flop on my edges. I love seeing hairs just fly off my arm after using my spyderco fine stone, but the aggressive cutting of a 320 grit edge is just SO addictive! Sometimes I compromise and use a 1200 grit diamond edge.

It's all good though, and it's fun to practice and get better at sharpening regardless.
:respect Spyderco : Resilience, Tenacious, Persistence, Manix 2 G10, Para 3 G10, Para 3 LW, Paramilitary 2,
BBS Paramilitary 2, Amalgam, Native Chief, Blade HQ Manix 2 XL, S30V Shaman, Gayle Bradley 2, DLC M4 Shaman, Magnitude, Z Wear Shaman, DLC S30V Shaman, Stretch 2, Kapara, CF/S90V Native Chief, Endela, K390 Endura, DLT 20cv Zome Endela x 2, Police 4 LW K390, SNK Native Chief, SNK Manix 2 XL, K390 Stretch 2, Stretch 2 XL, K390 Endela
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