Can't make ZDP shave, doing something wrong?

[Raylas]

I recently got a laminate ZDP caly for my birthday, and I've been doing some sharpening work on it. I got it sharp enough to cut a circle in phone book paper, but it won't shave hair. Am I doing something wrong, or does it just not shave very easily?

[Cliff Stamp]

ZDP-189 is very difficult to grind and in general, depending on the nature of your hair and how you are shaving, shaving can be a little or a lot higher than cutting a circle in phone book paper. It is possible to get it to shave cleanly.

[Raylas]

Hm, well I DO have very fine hair on my arms and in general. Maybe I should take it back to the strop for a few minutes and try again.

[noseoil]

Use light pressure on the strop. Have a fine edge to begin with from your stones, and a very clean edge. Are you using a compound on the strop? If the angle isn't right, you won't be adding to the edge but dulling it.

[Donut]

Sharp enough to cut phone book paper, but not sharp enough to shave sounds like a burr. ZDP can be difficult to get rid of a burr.

It's funny that you mention the Caly 3. I am having some trouble getting my Caly 3 ZDP very sharp. I haven't given it the time I think it needs to make it sharp.

[Raylas]

Noseoil: DMT diamond compound.

Donut: As it happens you are CORRECT! There WAS a bur, I used a computer attached microscope to check before I stropped. It's gone now, and this thing is shaving pretty well. It's sharper than my navaja, which I pride myself on as one of my sharpest pieces.

[Donut]

Sweet. :)

[Buendia518]

I'm approaching sharpening my caly 3 for the first time, and it's still fairly sharp (shaves well with a little pressure). Is it unwise for me to approach this on the sharpmaker without diamond stones?

[Freman]

What angle can ZDP-189 be cut to without having to worry about edge retention?

[chuck_roxas45]

What angle can ZDP-189 be cut to without having to worry about edge retention?

This one's at 22/30. It holds it's edge quite well. I do think ZDP at over 30° inclusive is wasted.

[Cliff Stamp]

What angle can ZDP-189 be cut to without having to worry about edge retention?

What are you cutting, how are you cutting it, what finish are you using, how dull do your knives get before you consider them needing to be sharpened?

[DunninLA]

I'm approaching sharpening my caly 3 for the first time, and it's still fairly sharp (shaves well with a little pressure). Is it unwise for me to approach this on the sharpmaker without diamond stones?

If you are referring to the Spyderco Sharpmaker Model 204 optional diamond triangles (which I have), then No! Those are for reprofiling to a steeper angle, or reprofiling b/c of damaged edges (from chips, dings, or sharpening with a lousy electric or pull through sharpener), and remove a lot of material. Or for really, really dull edges from years of not sharpening.

If you have a reasonably sharp edge already, why not just very lightly touch it up with the white triangles, then a light stropping if you have a strop. Or if you have a strop, start there first and only go to the white triangles if it seems its not sharp enough still.

P.S. this is why I think there should be a sub-section to this Forum dedicated to sharpening tips and questions.

[DunninLA]

This one's at 22/30. It holds it's edge quite well. I do think ZDP at over 30° inclusive is wasted.

What about 30 with a microbevel at 40?

[Evil D]

Sharp enough to cut phone book paper, but not sharp enough to shave sounds like a burr. ZDP can be difficult to get rid of a burr.

It's funny that you mention the Caly 3. I am having some trouble getting my Caly 3 ZDP very sharp. I haven't given it the time I think it needs to make it sharp.

Ding ding ding. If it will slice paper but won't shave, that's a burr no question about it. A burr will have enough bite to slice most things but won't shave worth a crap (though I have had burrs that will shave in one direction and not the other).

And, you mentioned the Caly 3 ZDP....I often credit this knife for teaching me how to sharpen. It was my first experience with ZDP and mine pretty much beat me into submission and forced me to take a big step back and relearn how to sharpen. The big lesson to learn here is to just go back to the basics and take it slow. The catch with this steel (and many like it) is that the simple mistakes you can make with a steel like AUS8 or VG10 and "get away with" simply aren't acceptable with ZDP and make themselves known much more. With VG10, you can get away with leaving a little burr and then strop a couple times and be able to straighten it out and have a sharp edge. What this does though is mask your development needs as a sharpener, and in the long run give you a false sense of worth with a strop too because of how the strop is standing up the burr on your edge and in the long run leaving you with a weakened edge. So, some basics to think about:

1. Use a Sharpie on the bevel to ensure you're sharpening the entire bevel and/or more importantly that you're hitting the very edge when doing your final strokes

2. Use a bright light source to check for reflection on the edge. This is CRITICAL especially with ZDP because you can (and want to) completely avoid raising a burr in the first place. As you're sharpening, routinely check the edge under a bright light to see if it's reflecting light. If it reflects light, the bevel hasn't come to an apex yet. Once you get to the point where very little light is showing, you know you're getting close....then it's time to lighten up your strokes and bring it to an apex without raising a bunch of burr. Once it doesn't reflect light anymore, you've essentially sharpened the knife.

3. Increase your angle a few degrees and make a couple very very light, very very short strokes on the very edge to cut off any burr that might be there. By this point your edge should be sharp, not reflecting any light, and should shave/slice with ease.

Do all that and you won't need a strop at all unless you want to polish the bevel for looks...just make sure you go back and put a micro bevel on after you strop/polish. The important thing with ZDP is to first AVOID raising a burr to begin with, and if you do CUT the burr off, not strop it straight. ZDP isn't exactly brittle, but it definitely is more likely to chip than roll, and those burred teeth will chip the first time you cut something which will ruin your sharp edge in a hurry.

Oh....and I forgot probably the most important detail that I don't think many people do....DESTRESS YOUR EDGE before you sharpen. Take the knife and run it very gently (just the weight of the knife itself) straight into a very fine sharpening stone as if you were trying to cut the stone. This will cut off the old weak metal and give you a nice clean plane of metal to work with. This will also give you a nice shiny edge under light that you can watch go away as you sharpen. Can't stress the importance of this enough....

[Raylas]

Evil D: What happened to me was that I did enough work on it to straighten the burr, but not QUITE enough to cut it of on the stones. I checked with a flashlight after Donut posted and sure enough, there it was. I was excited to work on my new knife, and I forgot rule number one: If you have a steel you don't know.... talk to somebody that DOES know it. Thanks for the advice on how to sharpen without raising a burr, I've never been able to figure that out. I'm still new to sharpening, so a LOT of steels are out of my skill level yet. Your post should be really helpful to me, especially with ZDP.

The de-stressing is good advice, I'd heard people refer to it, but never how to DO it.

[dschur]

I found my ZDP Spydies (Stretch, Caly 3, Caly 3.5) are virtual scalpels sharpened on my Wicked Edge at 30 degrees, I take them down to 1 micron strops, and hand strop them afterwards (maybe this is how I "distress the edge"?)

They are the best slicers I have, bar none. And they hold that edge quite a while.

Thinkin Maybe I should try that 30/22 and cut through time itself ;-)

[chuck_roxas45]

What about 30 with a microbevel at 40?

Sure it will still get sharp and cut but IMHO, it loses an edge quite faster than when it's at a lesser angle. 40° is bordering on too fat IMHO. You can tweak the sharpmaker's 40° setting to around 36° by pinching the rods or using a rubber band. The jump from cutting performance and edge holding from 40° to 36° is quite noticeable.

[Raylas]

^Nice trick, gonna test that out this weekend!

[Freman]

If you sharpen on an Edge Pro I'm guessing that you'll finish the edge with your finest stones cutting into the blade in order to clean off any burrs.

So 11° per side with a 15° microbevel?

I admit, I'm looking longingly at a ZDP Dragonfly.

Must resist... at least until I have more money.

[chuck_roxas45]

If you sharpen on an Edge Pro I'm guessing that you'll finish the edge with your finest stones cutting into the blade in order to clean off any burrs.

So 11° per side with a 15° microbevel?

I admit, I'm looking longingly at a ZDP Dragonfly.

Must resist... at least until I have more money.

Its easy to cut off a burr with the EP even with the. coarser stones.