Some odd things going on sharpening an endura in zdp 189

S

Spartan00

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Feb 4, 2016
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Hey guys . Found and old endura I haven't used in a awhile . It's the Saber grind and I'd thought itd be fun to zero grind/sharpen it .

Fast forward and I finally got the scratch pattern from the grind line to the edge .

I started out with a 220 diamond as well as a 220 beston just to get an idea how fast the different stones cut .

Anyway on my 220 stones I had a nice even scratch pattern from grind to edge.

I went up to my 320 stone refining the scratch pattern here's where things got interesting .

After the 320 I went to 800 and my uniform scratch pattern wasn't so uniform anymore . I have what looks like low spots in the grind mid way from grind to edge on one side that the 220 scratch pattern will not come out for lack of a better word.

My first thought was my stones were dished , so I changed to another 800 same problem,lapped my stones and nothing .even tried other stones I know are dead flat and still I can't hit the middle of the bevel on one side . One side is just fine and acts like it's supposed to .

Again I thought my stones just weren't flat . After a few stones ,as well as more lapping I'm thinking this isn't the case . Suggestions ?

I'm thinking I'm going to haft to go back to the 220 and grind off more steel on the one side . Again the grind is zeroed now though so when I put it on the stone I am getting a burr I just have a low spot in the steel

Should I just live with it and use it ?
 
Another possibility is the bevel pushed over a little on one side and now has a contact area like a micro hollowgrind. More likely on lower RC, but any steel thinned out enough at the bevel can have this happen. Assuming it isn't from a warp, the fix is to grind it back out.
 
If it doesn't effect the sharpness or use, I vote use it and work it out over time.
 
HeavyHanded said:
Another possibility is the bevel pushed over a little on one side and now has a contact area like a micro hollowgrind. More likely on lower RC, but any steel thinned out enough at the bevel can have this happen. Assuming it isn't from a warp, the fix is to grind it back out.
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I think it is like a micro hollow grind . Wonder why the 220 will hit it but the 800 and 1000 grits won't . I can live with it rather than just keeping on grinding off good steel. A 220 grit edge with a clean apex is a hell of a slicer.I guess if it bothered me too much I could go to sandpaper and a softer backing to get the scratch pattern out but he'll I'm babbling I'll keep it as is.
 
Spartan00 said:
I think it is like a micro hollow grind . Wonder why the 220 will hit it but the 800 and 1000 grits won't . I can live with it rather than just keeping on grinding off good steel. A 220 grit edge with a clean apex is a hell of a slicer.I guess if it bothered me too much I could go to sandpaper and a softer backing to get the scratch pattern out but he'll I'm babbling I'll keep it as is.
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The mud from the 220 would be large enough to "fill" the hollow, at least enough to frost the bottom of the hollow in a lapping action. Once you get to finer abrasive it can no longer quite reach.

Is also possible when it was initially sharpened was on a wheel and the hollow is still there to some extent. If its one you've owned a while I'd stick with the folded edge theory.

I've seen it before.
 
HeavyHanded said:
The mud from the 220 would be large enough to "fill" the hollow, at least enough to frost the bottom of the hollow in a lapping action. Once you get to finer abrasive it can no longer quite reach.

Is also possible when it was initially sharpened was on a wheel and the hollow is still there to some extent. If its one you've owned a while I'd stick with the folded edge theory.

I've seen it before.
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Interesting thing is the beston or bester 220 doesn't produce a mudd. It a very coarse stone almost looks like swiss cheese, CKTG had it but it's not there anymore but it's a great stone none the less.

I'm 99.99% sure it was a low spot when they ground the bevels. I went back to the stones but this time I went with diamonds .

Not too crazy about the deep scratches of coarser diamonds I just got the Ole standby 3x8 dias harp coarse. Bout 30 45 minutes got it even but now I have a scratch pattern above the grind line on the shallow side .

No big deal though I'm going to run it through the grits to get a mirror polish along the whole grind (my intentions to start with).

Anymore work I'll bring the grind up on both sides with a belt sander .

On another note this knife is now amazing . I've had my share of zdp 189 but it's all been in FFG spydercos .

Treating the Saber grind like a shanogi on a Japanese knife and sharpening out the secondary bevel transforms this knife .

Even at a 220 grit Waterstone finish it will push cut magazine paper completely vertical .

I wish spyderco would offer more zdp Saber grinds , except without the secondary bevel.

IIRC cliff stamp did a delica the way I did this endura and I believe he measured it at 6DPS if that can give anyone the sharpness level.
 
I've come across micro hollow grind edges before, but not on a Spyderco. My AL Mar ultralight came with bevels like that both sides, obviously cut on a wheel of some sort. The 10" wheel on my wet grinder makes a hollow bevel technically, but its nothing you'd notice sharpening by hand.

If the edge wasn't turned then there's only one other explanation, it came that way.
 
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