Reprofiling ZDP......from a self admitted novice

dbcad · #1

I'm always a bit cautious before trying any serious modification to an edge made of this stuff. Over some time I've been able to pound some facts through my very thick skull on the best way for me to deal with this material :o

First it's helpful to know something about the material itself. ZDP189 is a bit of a crazy animal being composed of 3% carbon and 20% chromium. After being heat treated to 64~65 Rc it becomes an extremely hard and stubborn blade that resists attempts to change it

Precisely why it makes such a good blade material in the first place.

My first step now is to first adopt the correct mindset. ZDP likes to play by it's own rules and doesn't take kindly to being forced. The next preparetory step is understanding that it will take some time and to be at peace with that fact

The most important thing is to use lighter pressure and not to try and force it. If you try to push ZDP too hard it will fight back and will actually take a hunk of edge off if you raise a large burr :eek: Patience and time will yield the best results :D Checking frequently with a loupe helps the time go by

Hopefully these insights will help an individual sharpening ZDP for the first time. For me, a self admitted novice at the art of sharpening, playing with this material and overcoming it's challenges has helped me to understand more and appreciate what I'm doing to an edge :D

BTW the results were fantastic :D

Evil D · #2

Rule #1 with ZDP, you actually want to AVOID making a burr.

Rule # 2 with ZDP, refer to Rule #1.

You wanna bring the apex just to the point that it's about to burr, and then switch to finder grit stones and continue until you have the edge honed out. When ZDP burrs, it chips very easily, and then you're in for a lot of frustration and a lot of work. If you get too aggressive and put too much force into it, you'll just chip it some more. Take your time and let the stones do the work.

jackknifeh · #3

Sometimes whan we (me) are learning something and really seeing progress in our skill and performance something jumps up and humbles us. ZDP-189 was my humbler. I remember your frustration too db. I'm glad there weren't hidden cameras in your house so we could see you bursting into tears. :) . Or my house for that matter. :D Being in the right mindset as you put it means establishing a specific plan on what angles you want and how to get the results. Already have the stones selected you are going to use, strops, etc. What Evil said about not letting a big burr develope is reall good advise also I think. For me, when I finally got to where I could sharpen it as easily as VG-10 it was like clearing a hurdle that had been tripping me up for some time. I have to say I'm loving my ZDP Manbug more every day. I have a ZDP D'fly on my wish list also. Of course that doesn't mean much since I've had every D'fly (current) on my list for almost 3 years. One problem is Spyderco keeps making new knives that bump the D'fly down on the list. Sage4, Manbugs and I hope the Chaparral is next. That's a bit expensive for me so it'll wait.

Glad your knife came out good. Hopefully now just a touch-up from time to time will keep it is great shape. BTW, What angles did you reprofile the edge to?

Jack

dbcad · #4

I included the most unflattering picture of the edge I could muster

Agreed with both of the comments. Creating a burr is not desirable when sharpening this stuff, hence the light pressure, frequent changes in side, and frequent checking with a loupe.

ZDP was my big humbler also given I don't posess a great deal of natural talent.

I took the angle pretty tight, around 20 to 25° inc. No micro bevel yet as this blade sees lighter use and is not cutting cardboard and zip ties. Another bevel will come in time :) I'll enjoy the insanity for a bit longer

unit · #5

Evil D wrote:Rule #1 with ZDP, you actually want to AVOID making a burr.

Rule # 2 with ZDP, refer to Rule #1.

You wanna bring the apex just to the point that it's about to burr, and then switch to finder grit stones and continue until you have the edge honed out. When ZDP burrs, it chips very easily, and then you're in for a lot of frustration and a lot of work. If you get too aggressive and put too much force into it, you'll just chip it some more. Take your time and let the stones do the work.

Personally, I always liked to generate a burr with ZDP, but I always use a 10x lens or greater to spot it early.

The most powerful advice I have offered for ZDP is to use a very light touch! It is hard and seems to skid across the hone, but the hone is doing more than you think, and added pressure will compromise the results (or at least is did for me...every time!)

I use a lens to grind to the edge with moderate pressure then as I approach the edge, I back WAY off the pressure and sneak up on the apex. The results are amazing!

dbcad · #6

Good to hear from you Ken :) Although the technique of a consistent light touch I've adopted seems to work very well, the next time I want to reprofile one of these blades I might try your sneak attack approach :D

I hope you are doing well :)

unit · #7

ehh...things are going pretty well...sort of...

I have evolved in my interests a bit. Still love Spyderco knives, but have gotten a bit (a lot) more serious about competitive cutting, and have gotten into honing razors (which, shall we say, is a bit more involved than knife sharpening

).

I always thought I knew how to sharpen a knife pretty well, but razor honing has taught me a few new tricks :D Competitive cutting has offered me an avenue to test my old methods and new methods as well as play around with some of the ideas I see touted on forums from time to time, and I have been learning a lot.

As a result, I have spent a bit less time on public knife forums lately.

jackknifeh · #8

If you haven't already, check out phillipsted's thread on sharpening 20CP. He has a picture showing a sharpening angle plan that I think would be good for ZDP if you use it for harder cutting than opening envelopes and such. The very edge would be the angle to use for touch-ups. It is 40 deg incl. so the Sharpmaker would handle that well. Of course none of the angles have to be exactly 40, or 30, etc. This is always thru but getting the angles in the neighborhood would be good IMO.

Jack

jackknifeh · #9

unit wrote:ehh...things are going pretty well...sort of...

I have evolved in my interests a bit. Still love Spyderco knives, but have gotten a bit (a lot) more serious about competitive cutting, and have gotten into honing razors (which, shall we say, is a bit more involved than knife sharpening ).

I always thought I knew how to sharpen a knife pretty well, but razor honing has taught me a few new tricks :D Competitive cutting has offered me an avenue to test my old methods and new methods as well as play around with some of the ideas I see touted on forums from time to time, and I have been learning a lot.

As a result, I have spent a bit less time on public knife forums lately.

I think I'd like to hear some of the new "tricks". Recently, I've gotten interested in getting my knives sharper than I have so far. I'm looking into really fine diamond sprays or pastes like .1 micron and such. Just bought some 1 micron Boron Carbide that I really like. So, if you would share any tid bits I'm sure some of us would appreciate it.

Normally, pocket knives don't need to be as sharp as a razor. Folding pocket knives are not the tool to shave with even if they are sharp enough. Still, just for fun I'd like to improve my sharpening skills. I know how sharp I consistantly get my knives. But, just like a lot of you I bet, once in a while I get lucky with the last coupel of strokes and end up with an edge that blows my mind. My goal is to get that level of sharp consistantly. That means improving my skills, maybe my tools but definately my skill.

Jack