My de-curved recurve ZT and Sharpmaker experience

[Moto54]

Used my brand new Sharpmaker to put a nice edge on my de-curved recurve ZT 0350.
A few thoughts: I dont see the point of paying for the powdered steel of my Elmax
0r CTS 204P zt's when the factory edge is so coarse! Nevermind that I prefer a 30
degree bevel. The level of finish on the edge itself is enough to embattle the
poor gray sharpmaker stone. Also, using a decent sharpener for the first time was
like a lightbulb going off in my head. Finally a way to feel what a mirror polish
bevel feels like (I got the ultra fine stones too.) The main learning was knowing
when back off the pressure and allowing the edge to skate over the stone.

It seems foolish now to have thought my PM steel zt's were fine the way they were.
I put some reading glasses on under a bright light and those factory bevels were
crazy coarse. No way they were taking advantage of the blade steel.


image ru

I removed the recurve using a Dremel.

 

[NJBillK]

One thing you might notice by pulling the heel up. Yes, you did remove the recurve, but in the process you added more belly in relation to the handle angle.
You should see a Significant increase in pull cutting effectiveness.

I made my Becker BK11 a friction folder. To allow the blade to tuck into the handle how I had it set up, I had to pull the heel up. The First thing I noticed about how the knife reacted to that simple blade mod was a vast difference in pull cutting over my BK24 with a toothy 600grit and stopped edge, and over the stock profile of the BK11.

Good Job, let us know how it performs.

 

[Moto54]

One thing you might notice by pulling the heel up. Yes, you did remove the recurve, but in the process you added more belly in relation to the handle angle.
You should see a Significant increase in pull cutting effectiveness.

I made my Becker BK11 a friction folder. To allow the blade to tuck into the handle how I had it set up, I had to pull the heel up. The First thing I noticed about how the knife reacted to that simple blade mod was a vast difference in pull cutting over my BK24 with a toothy 600grit and stopped edge, and over the stock profile of the BK11.

My biggest surprise so far has been how stoked I am having the Spyderco Sharpmaker.. my knives never had it so good.
To get the most out of it means wearing some magnification on my eyes, not because I'm half blind or anything, but its kind of fun to TRY to find
imperfections, now that I can finally sharpen.

I hear you about the new cutting geometry.
Another side effect of the sharpmaker is that now I want to use my knife more and not baby the edge.
Your mods sound cool! Whats it look like then?

 

[bflying]

Isn't S30V a powdered steel also? It's just a little older than Elmax and 204P. Interesting mod for sure. Maybe not my cup-o-tea since I have plenty of other knives without re-curves. But I'm blown away you did that on a Sharpmaker. That's a lot-a work. I love my SM's, but only use them now for edge touch-ups, which is what they do best IMO.

Initially I wondered about the re-curve on my 350TS also, and how effective it would be, and how hard to sharpen. I soon learned that I liked the re-curve for certain cutting tasks, which were the type of tasks that I would pocket this knife for anyway. And on the sharpening factor, I spent a little more time (probably over an hour or more) doing my first sharpening on an Edge Pro. But the real reason for the length of time is that I wanted to re-profile so both sides had perfectly even bevels....and I took it to near polish finish. Mine must have been a Monday Morn or Friday Afternoon production as the factory sharpening looked like it had a nice wrist roll in it. If I'm paying over $100 for a knife, I want an even bevel (front to back, side to side). I'm just picky that way. But now that I have a "few" hours under my belt with multiple sharpening systems, I usually just fix most blades that come to me a little sloppy on the edge.

Thinking back, the polished edge was a little counter productive for that knife, but the re-curve compensated for the slick slicing. So far it's only needed a little quick touch ups on the sharpmaker since. If I ever need to do another full sharpening, will most likely leave it just a tad toothy.

On my last ZT's (more than a dozen), I have not had issues with the out-o-box edges. But I did find it a little ironic that the half dozen Kershaw Blurs I've brought in had better edges than my first ZT 350. Not sure if it's an issue with just that blade shape, or the person doing final grinds.

I should add: OP, if you are that excited about the SharpMaker (I like 'em too for certain things), then you would go absolutely Bat Crap Crazy over the simple KME Sharp system with gold diamond stones and a strop or two. Talk about next level edges. Look them up. I do a signature "Jeweled" (swirled) edge on my personal knives, and it totally freaks out everyone I show them off to. And yes, most everyone cut themselves upon examination of my knives before handing back over. Sometimes it's just inexperience in handling and/or sharpness testing by feel, but also everyone wants to touch the sparkly edge bevel, and.......WHAM!, they get bit. So much fun to watch. Is is sadistic to enjoy watching someone else get bit, bleed, then hand my knife back with the comment..."Damn that's sharp". ?

 

[ocnLogan]

Nice work .

Just wanted to point out, that the coarseness of the secondary bevel has really nothing to do about getting the most out of the steel. The steel is much more about what edge angles it can support without failing. Coarse/fine bevels are pretty much independent of the steel. Some people prefer coarse ("toothy" edges), that act somewhat as micro serrations. Just because an edge bevel is "coarse" doesn't mean that the apex can't be very precisely fine.

I'm not a big fan of guided systems personally, but I hear that many people have good success with them. I prefer to freehand sharpen. Typically, I don't have any problems getting any of my blades to shave arm hair, and can get most to the point that they'll whittle beard hairs (I don't typically worry about that though), hence why I've felt no need to spend the money on a fancy guided system (and the skill doesn't take up any space in my already crowded apt).

Anyway, congrats on getting the blade how you want it .

 

[Moto54]

Lots of things included in the replies above! Since I'm short on time I just want to comment about blade steels and bevel finish.
Obviously it doesnt take a sophisticated modern technology to produce a 'sharp' edge on steel.. I'm sure the ancient Romans were
happy enough with the killing power of their Gladius or whatever. But if modern technology produces an ultra pure and refined
process for including other elements and acheiving a superior alloy, then that alloy would allow better performance out of a
thin angle and super sharp edge. Dont you agree with that?

You could put a sharp edge behind narrow stock using roman era steel, but it would not be expected to stay as sharp as long as say,
Elmax, or whatever. And I wasnt saying that a powdered steel is not good at other uses, or would be. Conceptually, a powdered steel with
evenly distributed carbides is going to favor exploitation along certain lines as far as a knife edge goes. A coarse bevel in front of
thick stock using 204P is going to be very strong and durable- but it doesnt exploit the materials potential in the same way as a smooth
bevel in front of less thick stock.

Lots of great things to think about in those replies though!
I will check out the KME.

EDIT: to be honest I dont have very much call to use my knives on a daily basis. If I was pooping myself over self defense measures that much I
would probably just buy a 9mm, or if I had to face a pile of boxes to take down everyday (?) I probably wouldnt buy an expensive pocket knife to do it.
I love my knives mostly as an expression of modern design and technology. The fact that I can draw and deploy my ZT 350 at throat heigth in way
under a second (starting with my hand in my pocket) is icing on the cake. Also, M390 is exceptional at cutting cake.

 

[ocnLogan]

Lots of things included in the replies above! Since I'm short on time I just want to comment about blade steels and bevel finish.
Obviously it doesnt take a sophisticated modern technology to produce a 'sharp' edge on steel.. I'm sure the ancient Romans were
happy enough with the killing power of their Gladius or whatever. But if modern technology produces an ultra pure and refined
process for including other elements and acheiving a superior alloy, then that alloy would allow better performance out of a
thin angle and super sharp edge. Dont you agree with that?

You could put a sharp edge behind narrow stock using roman era steel, but it would not be expected to stay as sharp as long as say,
Elmax, or whatever. And I wasnt saying that a powdered steel is not good at other uses, or would be. Conceptually, a powdered steel with
evenly distributed carbides is going to favor exploitation along certain lines as far as a knife edge goes. A coarse bevel in front of
thick stock using 204P is going to be very strong and durable- but it doesnt exploit the materials potential in the same way as a smooth
bevel in front of less thick stock.

Lots of great things to think about in those replies though!
I will check out the KME.

EDIT: to be honest I dont have very much call to use my knives on a daily basis. If I was pooping myself over self defense measures that much I
would probably just buy a 9mm, or if I had to face a pile of boxes to take down everyday (?) I probably wouldnt buy an expensive pocket knife to do it.
I love my knives mostly as an expression of modern design and technology. The fact that I can draw and deploy my ZT 350 at throat heigth in way
under a second (starting with my hand in my pocket) is icing on the cake. Also, M390 is exceptional at cutting cake.

Yep .

I was just saying that the grit/finish on the edge bevel being coarse doesn't necessarily have much to do with "sharpness". I'm in total agreement about newer/fancier steels being able to support more acute edge angles without failing. But just saying the stock edge was "coarse" (like it was sharpened on a low grit stone/belt) doesn't mean the same thing as "the edge angle was a bit obtuse/thick/etc", which I "think" is what you're saying there. I could obviously be wrong though, so feel free to correct me if I didn't understand you right.

What I was also saying is that there are uses for "coarsely finished" bevels. This does NOT mean that they can't be sharp, it just means they're not polished smooth, but BOTH edges can have very accurate apexes (the "sharp" part of the edge). I've seen people shave hair with an edge that was sharpened on 320 grit, and then others do the same with a different knife at 6000 grit. Some people prefer coarser (yet still properly sharpened/apexed) edge finishes because it works well for the tasks they do. A common thing many people say about edges like this is that they are almost like micro serrations. I most commonly have heard this coarse edge type from hunters who say it works great for dirty boar/bear hides, although by no means do "all" hunters like it.

Personally, I do go to a high grit and polish my bevels, so I don't have a horse in this race . I was just trying to decouple the "edge finish" from the "edge angle" part of the discussion, as they're different things.

And again, I'm not into knives for anything like self defense, but I get the desire. So again, congrats on the new steel, and for making it just how you want it :thumbup:.

 

[Moto54]

I was just saying that the grit/finish on the edge bevel being coarse doesn't necessarily have much to do with "sharpness".

My tendency is to imagine a 30 degree mirror bevel on PM steel as the king of knife edge
sharpness based on the quality of the steel itself. If a 30 degree coarse bevel can be made
equally sharp (and I dont know that it can) it would remind me of a neat deck-of-cards fact:

Starting from a shuffled deck of cards, the probability of shuffling the deck again and
getting the cards arranged by order of suit and number is like, 1 in 10 followed by 67
zeroes. So that represents a 30 degree mirror bevel.

But in fact, and its a bit of a surprise-- any random suit and number sequence in a deck of
cards (ANY sequence) has the same probability of being reproduced in a shuffled deck as the
seemingly more improbable order by suits, etc. That fact represents 30 degree coarse
bevel sharpness to me

How big is a 10 followed by 67 zero's? If you sharpened and resharpened a coarse bevel once
every second, never stopping day or night and going backward in time, you would reach the
Big Bang and not be half way to making that coarse bevel as sharp as a mirror polish.


Actually what we need is a sharpness App that would magnify a high res photo of an edge
and spit out a sharpness-attained number compared to a digital ideal. Think of all the
arm hair and paper we could rescue.

 

[Insipid Moniker]

The advantages of the steels you list don't have much to do with having an exceedingly sharp edge. In fact, steels with very small grain size and few carbides will, theoretically, take a finer edge than PM steels with high carbide content. The advantage of those steels is that they have extreme abrasion resistance and will hold a working edge when cutting abrasive media for a very long time. To that end, a coarse, almost micro serrated, edge that cuts very aggressively can actually be advantageous.

 

[ocnLogan]

Save the arm hair and paper!

As Insipid Moniker mentioned, the steel itself doesn't actually make an edge any sharper (or duller). When you're cutting, its basically all about geometry. The more acute of an angle (providing it meets at the edge correctly), the sharper it will be. What I was getting at was that the angle of the secondary bevel (the part that gets polished when you sharpen to a very high grit) isn't influenced/changed by the grit its sharpened at. As long as the apex (the exact "tip" of the edge) is met correctly, a coarse edge can still be sharp (just make sure to get the burr off). In fact, technically all sharpened edges will be "micro serrated", its just that the fineness of the grit will dictate how big the "teeth" of the microserrations are.

What better steel DOES let you do, is to make the edge angle more acute than a lesser steel, while not letting the edge get damaged. You may be able to sharpen a junk 420j steel to a 10 degree angle, but it likely wouldn't hold that edge very long at all. The same edge angle would last a WHOLE lot longer if it were made with CPM-3v/10v (or any other number of much better steels). Conversely, you could think of it as the 420j steel blade needing a 60 degree angle to only need sharpening once a week, while a better steel might be able to support a 20 degree angle for the same week. In this case the better steel "is" sharper, but not because of the steel itself, but because what it allows you to do.

Anyway, I really didn't want to derail the thread. Its just that those two things are different, and they took me a while to wrap my head around, so I was trying to help clarify. It appears that maybe I just muddied the waters a bit :/.

Cheers .

 

[Moto54]

Save the arm hair and paper!

Anyway, I really didn't want to derail the thread. Its just that those two things are different, and they took me a while to wrap my head around, so I was trying to help clarify. It appears that maybe I just muddied the waters a bit

I like hearing what Insipid Moniker and yourself have said. Very much.
I have a cheapee kitchen kinfe someone gave me and that sucker can be made really really sharp! So thats in keeping with having less carbides/sharpness.
If its just a matter of sharpness in isolation-- sharpness 'in the lab' so to speak, the qualities of PM steel dont mean very much. If its about use and utility,
then that throws the doors open to whatever it is you are needing to do.. serrations, recurves, big belly, no belly, etc. ..as well as opening the door to what
PM steel can offer.

So this leaves me and my ZT 562CF a bit like someone who has an F1 car in the garage but no place to show what it can do,
while my neighbor in his razor sharp no-carbide 91' Ford Escort goes merrily on his way.
What kind of crap is that!