ZDP Hard to Sharpen

[jnichols2]

I decided to sharpen my ZDP-189 Caly 3.5 today. It took me over an hour.

I had to go to the diamond rods to redo the left edge angle. After that, it took three trips through Medium, Fine, and Ultra Fine to get it really sharp.

Now that I'm finished, the edge is much smoother than any of my other knives, which all have "toothy" edges.

I'm satisfied with the result, but my ZDP Ladybug was MUCH easier to sharpen. :rolleyes:

[Ankerson]

ZDP is a high alloy steel with 20% Chromium and 3% carbon designed to be run at high hardness in the 64-68 HRC range so it would be somewhat harder to sharpen than the other steel.

It's the carbides and the high hardness of ZDP that causes that, but the payoff in edge retention makes it worth it.

[jnichols2]

ZDP is a high alloy steel with 20% Chromium and 3% carbon designed to be run at high hardness in the 64-68 HRC range so it would be somewhat harder to sharpen than the other steel.

It's the carbides and the high hardness of ZDP that causes that, but the payoff in edge retention makes it worth it.

Actually, I'm not sure the edge retention on my two has been all that much better than my CPM S30V knives. But, the Caly 3.5 is definitely one fine knife.

[Holland]

Yep sharpening ZDP can be a PITA, best to touch up ur blades frequently

[Cliff Stamp]

After that, it took three trips through Medium, Fine, and Ultra Fine to get it really sharp.

If you didn't move past the medium until it was smoothly shaving, push cutting newsprint, etc. it would be much faster.

[jnichols2]

If you didn't move past the medium until it was smoothly shaving, push cutting newsprint, etc. it would be much faster.

I didn't realize it would shave or push cut on Medium. :confused:

[Cliff Stamp]

The edge can shave off an even more coarse finish, but the medium is relatively high grit wise and can easily push cut newsprint. The fine and uf remove very little metal so the edge should be very sharp before you go to them to minimize time on the rods.

[jnichols2]

The edge can shave off an even more coarse finish, but the medium is relatively high grit wise and can easily push cut newsprint. The fine and uf remove very little metal so the edge should be very sharp before you go to them to minimize time on the rods.

Thanks Cliff.

[Evil D]

It really helps with ZDP if you use a loupe when sharpening, and pair that with a sharpie marker to make absolutely sure you're hitting the edge. If you're hitting the shoulder, you'll be making 1000s of strokes before you wear it down and hit the edge and start making it sharp again. ZDP is not a steel for lazy sharpeners...you've gotta maintain that edge or you'll end up hating the knife. The longer you go between touch ups, the longer you can expect to spend sharpening it.

[JD Spydo]

I've told people this several times but yet few people believe me>> I truly find the older 440V ( S60V) of Crucible's to be harder to sharpen than ZDP-189. And I find XHP to even be just a bit more difficult to work with than ZDP.

I like what Cliff Stamp said about using the medium stone on the 204 Sharpmaker until you get an edge that you can shave arm hair off with. I've been doing just that here in the past 4 months and it does seem to work pretty well.

When I do sharpen either one of my ZDP blades I mainly use 2 of my diamond benchstones to reprofile with unless I'm using the 204 Sharpmaker then I use the 204 diamond stone to do a lot of the hard work and the medium to set it up for a final finish.

But to me ZDP is not one of my worst steels to sharpen. I even find some of the other tool steels to even be a bit more stubborn at times.

[chuck_roxas45]

ZDP IS hard to grind but once you've put on a proper bevel, it's easy to touch up with the sharpmaker. Removing so little steel(with a microbevel) doesn't really need a lot of grinding.

[jackknifeh]

I agree with Chuck about the micro-bevel on ZDP. Cutting is easier with low edge angles. But ZDP is so hard it's VERY difficult to get the edge sharp and maintain it with a wide bevel. Also, the hardness of ZDP means micro-chipping can be an issue at lower angles (below 30° inclusive). This is my experience anyway.

So, using a micro-bevel gives the edge more strength to reduce micro-chipping and makes touchups very easy. Touching up ZDP frequently on the micro-bevel (or edge bevel) will keep the knife sharp and keep you from needing to work on the back bevel as often.

ZDP is the hardest steel I had to learn to sharpen. I'm no pro. I'm only semi-experienced. But, once I knew what I wanted or needed to do it's a nice steel to use.

[phillipsted]

Personally, I find ZDP no harder or easier to sharpen than other steels. It takes the same techniques - it just takes L O N G E R to get a good edge.

Set a spell. Take your shoes off. Your patience will be rewarded!

TedP

[Brisket]

My personal revelation in sharpening came while working with ZDP and it was exactly what Cliff Stamp was referring to. I had acquired a dull ZDP Delica and to make an extremely long story short came to realize after great frustration and trial & error that I was overly concerned about removing excessive material with coarser abrasive and had developed a tendency to progress to a finer abrasive before it was time. ZDP helped me discover my sharpening flaws that were not obvious with sharpening softer steels and as a result my sharpening results on all steels improved.

[jnichols2]

It really helps with ZDP if you use a loupe when sharpening, and pair that with a sharpie marker to make absolutely sure you're hitting the edge. If you're hitting the shoulder, you'll be making 1000s of strokes before you wear it down and hit the edge and start making it sharp again. ZDP is not a steel for lazy sharpeners...you've gotta maintain that edge or you'll end up hating the knife. The longer you go between touch ups, the longer you can expect to spend sharpening it.

Evil,

I did use the sharpie, that was what told me to use the diamond rods to fix the left edge.

To others that recommended a 40 degree micro bevel. That seems like a good idea.

[Cliff Stamp]

As a general rule, if you are attempting to sharpen a knife and you are having to remove a lot of metal then there is a problem as knives, even when blunt, require very little metal to be sharpened. A sharp edge will be between 0.1 and 1 micron thick, even if it is blunted way down to 10% you are still only removing on the order of 10 microns of steel, 5 from each side to get it back to full sharpness. This should happen immediately unless you have an extremely wide apex bevel. If this is the case then lower the apex bevel angle, even 1-2 degrees below the desired final angle. Sharpening will then again become instant, and as necessary work the relief grind as needed, on the more coarse abrasives to keep the final sharpening bevel very small in width.

[phillipsted]

As a general rule, if you are attempting to sharpen a knife and you are having to remove a lot of metal then there is a problem as knives, even when blunt, require very little metal to be sharpened. A sharp edge will be between 0.1 and 1 micron thick, even if it is blunted way down to 10% you are still only removing on the order of 10 microns of steel, 5 from each side to get it back to full sharpness. This should happen immediately unless you have an extremely wide apex bevel. If this is the case then lower the apex bevel angle, even 1-2 degrees below the desired final angle. Sharpening will then again become instant, and as necessary work the relief grind as needed, on the more coarse abrasives to keep the final sharpening bevel very small in width.

You are absolutely right, Cliff. There is a huge difference between re-profiling and sharpening.

TedP