Spyderco Forums

pantagana23 wrote: ↑

Tue Feb 23, 2021 4:00 am

That's a micro-serrated edge

Here is a screenshot from the second vid (https://youtu.be/ChiFWYb7_VM).
Whatever it may be worth.

It's funny, this is what they would do to heads to get more flow. They would dimple(or just coarse finish) the roof portion of the valve ports and polish the floor.

The dimpled roof would cause turbulence in the air passing over it, forcing subsequent air to pass below on the shorter, polished section, increasing air velocity and decreasing the distance it had to travel to get to the combustion chamber.

Sometimes my brain takes weird paths with info... But, the more you know, right?

I've tried the coarse/fine grit combo on my SE blades, using diamond or CBN on the grind side and ultra fine on the back side. My thoughts were to just try to make as little bevel on the back of the blade as possible.

Evil D wrote: ↑

Tue Feb 23, 2021 8:48 am

I've tried the coarse/fine grit combo on my SE blades, using diamond or CBN on the grind side and ultra fine on the back side. My thoughts were to just try to make as little bevel on the back of the blade as possible.

:eek: ... in the context of this thread for me this is a bit like a "Davids casual bombshell"

Any results or impressions yet if edge retention did improve? If so, only in certain tasks?

A helpful screencap:

kobold wrote: ↑

Tue Feb 23, 2021 9:07 am

A helpful screencap:

Which you can find four post above yours already...viewtopic.php?p=1497374#p1497351 :D (no offense, that´s totally fine, and yours is a lot better made! :) )

Wartstein wrote: ↑

Tue Feb 23, 2021 7:49 am

Really, really interesting once more!

Especially, as said at the beginning of the vid, the guy that came up with the "250 / 6000 grit" -edge thinks it would be (quoting Cedric): "Truly versatile and form fitting for most purposes"

Also interesting what the "physics" / "mechanics" behind this findings may be. Paraphrasing Cedric: Is it more like that the coarse edge "leads" and when it breaks down the polished edge takes over? Or vice versa? Or something else?

Just a polite note: They guys name who makes the video(s), and who you are "quoting" and "paraphrasing" is, Pete. - Not Cedric-
Pete named the channel "Cedric & Ada" after his two (at the time) dogs. Cedric (RIP), and Ada the Husky.

As to the these sharpening videos, they are interesting. I wonder also, how much, if at all, does the grind direction come in to play? Which he mentions in the video.

u.w.

Isn't this how they already sharpen scalpels?

Wartstein wrote: ↑

Tue Feb 23, 2021 9:13 am

kobold wrote: ↑

Tue Feb 23, 2021 9:07 am

A helpful screencap:

Which you can find four post above yours already...viewtopic.php?p=1497374#p1497351 :D (no offense, that´s totally fine, and yours is a lot better made! :) )

Hah! Anyway, redundancy is good. Image hosting sites don't last forever.

Now, imagine doing this to Maxamet or 15V. Sharpen once, cry once... a year. :D

kobold wrote: ↑

Tue Feb 23, 2021 9:24 am

Wartstein wrote: ↑

Tue Feb 23, 2021 9:13 am

kobold wrote: ↑

Tue Feb 23, 2021 9:07 am

Hah! Anyway, redundancy is good. Image hosting sites don't last forever.

Exactly! :)

u.w. wrote: ↑

Tue Feb 23, 2021 9:17 am

Wartstein wrote: ↑

Tue Feb 23, 2021 7:49 am

Just a polite note: They guys name who makes the video(s), and who you are "quoting" and "paraphrasing" is, Pete. - Not Cedric-
Pete named the channel "Cedric & Ada" after his two (at the time) dogs. Cedric (RIP), and Ada the Husky.

As to the these sharpening videos, they are interesting. I wonder also, how much, if at all, does the grind direction come in to play? Which he mentions in the video.

u.w.

Thanks for correcting me!!

Now that you did I realized I even "knew" that... his channel is one of the few knife channels I watch occasionally.
One of his dogs died recently, as far as I can recall.

Wartstein wrote: ↑

Tue Feb 23, 2021 9:05 am

Evil D wrote: ↑

Tue Feb 23, 2021 8:48 am

I've tried the coarse/fine grit combo on my SE blades, using diamond or CBN on the grind side and ultra fine on the back side. My thoughts were to just try to make as little bevel on the back of the blade as possible.

:eek: ... in the context of this thread for me this is a bit like a "Davids casual bombshell"

Any results or impressions yet if edge retention did improve? If so, only in certain tasks?

I don't know that there's any sort of magic happening. The resulting edge is still toothy like it would be coming off diamonds. It seems to me the edge apex ends up being more of a chisel grind this way as opposed to being more of a double bevel V shaped apex. It isn't like there are two edges working together, you still have one apex, it's just smoother on one side.

I'm with you David, in that I don't know that there is any sort of "magic" happening.

What I'd be curious to see as a continuation, is to sharpen the same knife at the same angle, once at the lower grit, and once at the higher grit (250 & 6000 respectively, according to that drawing, I think), do the same rope cuts, and see what those numbers are.

u.w.

This does not work with Serratas, as these pesky micro serrations will not allow themselves be smoothed off on the one side... :D :cool: :rolleyes:

BTW...I applaud the efforts taken by all folk looking for something new in edge reforming, and as Sal said...
Share the info! :)

@Larrin, we need you to test this using the systems that you have to see if this can be proven with the scientific method.

This could change the way that manufacturers sharpen knives for retail!

I would like to see what a real edge under one of those digital microscope would look like.

Im interested, but right now I think whoever sharpened it just put a much better edge on it than the factory edge.

"Back in the day", when we were developing the Sharpmaker (late 70's), we felt that a coarse edge cut more aggressively but lost it's sooner and finely polished edges stayed sharper longer, but didn't cut as well, even slide on some lines. Our solution was a finely polished serrated edge.

But even serrations are available for testing and improvement. We're always trying to incorporate any new information into the factory edge. Eg; A serrated edge helps edge longevity by keeping the cutting edge off of the cutting board. On our K04 and K05 serrated kitchen knives, one tooth is longer to protect the other two teeth.

sal

sal wrote: ↑

Tue Feb 23, 2021 5:00 pm

" On our K04 and K05 serrated kitchen knives, one tooth is longer to protect the other two teeth.

sal

I've been looking for an explanation for the Spydie edge pattern of one large and two small teeth/scallops for quite a while. It makes sense now from an edge retention point of view as I have found that a serrated edge with one size that's the same as the large scallop on Spydies pretty much cuts just as well. One less mystery to obsess over. Thanks Sal!!! :p