how do you sharpen your recurve ZT350 or ZT300?

Legacy Forum Archive kershaw-zero-tolerance
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I am a new knife owner and now have a ZT 350 and the ZT560 along with a number of other Shun kitchen knives and a bunch of less interesting knives. I have been following as many forums and youtubes as I could but I have not really found anything showing or detailing how to sharpen the recurve portion of the blade. I have ordered a WEPS with diamond grit flat stones up to 1000 grit and a flat fine ceramic stone, but I have ordered a pair of curved ceramic stones that are labeled 400 and 600 grit. Since I am new to this whole world, I am not clear on whether the ceramic 400 and 600 stones are going to be finer than the 1000 diamond grit stones. Would the round ceramic 600 stone leave a mirror finish or is it just going to be the same as if I used a 600 grit diamond stone (but curved)?

Sorry if this is considered a dumb question, but I am very excited in anticipation of getting this setup. I want to order the right stones and accessories for my knives.

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Good questions - first I think you’ll be able to sharpen both those knives with the flat stones since the curves aren’t very tight. Second, the 600 grit ceramic is similar to the 600 grit diamond though the diamond will be more coarse until it’s broken in.

[quote quote=“ScottSherman” post=4812]I am a new knife owner and now have a ZT 350 and the ZT560 along with a number of other Shun kitchen knives and a bunch of less interesting knives. I have been following as many forums and youtubes as I could but I have not really found anything showing or detailing how to sharpen the recurve portion of the blade. I have ordered a WEPS with diamond grit flat stones up to 1000 grit and a flat fine ceramic stone, but I have ordered a pair of curved ceramic stones that are labeled 400 and 600 grit. Since I am new to this whole world, I am not clear on whether the ceramic 400 and 600 stones are going to be finer than the 1000 diamond grit stones. Would the round ceramic 600 stone leave a mirror finish or is it just going to be the same as if I used a 600 grit diamond stone (but curved)?

Sorry if this is considered a dumb question, but I am very excited in anticipation of getting this setup. I want to order the right stones and accessories for my knives.[/quote]

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I have posted on this before somewhere on the board (too lazy to look). I used my own naniwa stone setup and stropped with thick balsa using some CBn spray. YMMV

http://i1133.photobucket.com/albums/m599/SPIN1963/DSCN0115.jpg

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i did my ZT 0200 with flat stones no problems.

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What angle did I you use. I imagine the smaller the angel the more the flat stone would lay against the wall of the blade while a greater angel would result in the flat blade resting more in the High side of the valley of the recurve so that the sides of the flat stone will touch metal while the middle of the flat stone will have a empty space under it with no blade edge contact.

I guess my question then is what is the largest angel at which the entire flat edge of the stone is evenly touching the surface on the side of the edge. To make the point, for example, if I lay the flat stone 90 degrees perpendicular to the recurve section of the blade edge only the sides of the flate surface of the stone would be touching steel. At say, 5 or 10 or maybe even 15 degrees, I imagine most if not all of the stone would be in contact with the metal as it drags across the surface to sharpen the edge. But when (what angel) does the middle of the stone loose contact

Hope that makes sense, it’s a bit hard to describe.

I guess the way to calculate that would be to paint the side of the blade with a marker and draw a flat blade across it until it starts to loose contact in the center of the stone and it leaves sled marks. If someone with a ZT 350 can do that experiment it would be great. If not I will do it when I receive my WEPS system for you folks and document the angels with some pictures. I am not sure when that will be just yet but they said maybe a week or two + shipping time due to filling back orders before me.

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[quote quote=“ScottSherman” post=4822]What angle did I you use. I imagine the smaller the angel the more the flat stone would lay against the wall of the blade while a greater angel would result in the flat blade resting more in the High side of the valley of the recurve so that the sides of the flat stone will touch metal while the middle of the flat stone will have a empty space under it with no blade edge contact.

I guess my question then is what is the largest angel at which the entire flat edge of the stone is evenly touching the surface on the side of the edge. To make the point, for example, if I lay the flat stone 90 degrees perpendicular to the recurve section of the blade edge only the sides of the flate surface of the stone would be touching steel. At say, 5 or 10 or maybe even 15 degrees, I imagine most if not all of the stone would be in contact with the metal as it drags across the surface to sharpen the edge. But when (what angel) does the middle of the stone loose contact

Hope that makes sense, it’s a bit hard to describe.

I guess the way to calculate that would be to paint the side of the blade with a marker and draw a flat blade across it until it starts to loose contact in the center of the stone and it leaves sled marks. If someone with a ZT 350 can do that experiment it would be great. If not I will do it when I receive my WEPS system for you folks and document the angels with some pictures. I am not sure when that will be just yet but they said maybe a week or two + shipping time due to filling back orders before me.[/quote]

Makes perfect sense what you’re saying… so to answer your question, I took a flashlight and laid it so the light went down the stone, then laid a ZT0350 flat on the stone and began lifting to create an angle. As soon as you start lifting, the blade loses contact in the center and light shines thru.

But this isn’t what you need to worry about. Regardless of the angle you want to sharpen at, enough of the stone will contact to sharpen the recurve. The WE stones, also pivot around the rods, so the stones kind of “flow” (for lack of a better word right now) in and out of the recurve. The trick is to let them do that.

One thing I do on recurves is to work the stone both ways… from the heel out of the recurve, then start at the front of the recurve and work back toward the heel. (This also helps on other knives too, to reach the area right at the heel). You want to avoid “scrubbing” straight up and down in a recurve, like you see in some videos to create a burr… this can create a groove. Always have some motion across the blade. Also, never use alot of pressure… just let the stones work thru the recurve.

My suggestion. Mark the blade with a sharpie, like you suggested. When you get the WE, first practice on a regular knife until you’re comfortable with the WE, and how it works. Then, take the recurve blade and match the angle that is currently on the knife. Take your finest stone (not strop) and just lightly work the stone thru the recurve… paying extra attention to how it works in and out of the recurve area. I think you’ll quickly see how well the WE works in the recurve area.

Hope this helps! Cool to see your anticipation and excitement! :woohoo:

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[quote quote=“cbwx34” post=4829]

Makes perfect sense what you’re saying… so to answer your question, I took a flashlight and laid it so the light went down the stone, then laid a ZT0350 flat on the stone and began lifting to create an angle. As soon as you start lifting, the blade loses contact in the center and light shines thru.

But this isn’t what you need to worry about. Regardless of the angle you want to sharpen at, enough of the stone will contact to sharpen the recurve. The WE stones, also pivot around the rods, so the stones kind of “flow” (for lack of a better word right now) in and out of the recurve. The trick is to let them do that.

One thing I do on recurves is to work the stone both ways… from the heel out of the recurve, then start at the front of the recurve and work back toward the heel. (This also helps on other knives too, to reach the area right at the heel). You want to avoid “scrubbing” straight up and down in a recurve, like you see in some videos to create a burr… this can create a groove. Always have some motion across the blade. Also, never use alot of pressure… just let the stones work thru the recurve.

My suggestion. Mark the blade with a sharpie, like you suggested. Take your finest stone (not strop) and just lightly work the stone thru the recurve… paying extra attention to how it works in and out of the recurve area. I think you’ll quickly see how well the WE works in the recurve area.

Hope this helps! Cool to see your anticipation and excitement! :woohoo:[/quote]

Thank you very much for your response, I was a bit concerned that my question would not be interesting to anyone else since there are so few posts here regarding recurve knives. I really love my ZT350 recurve but it does present obvious problems for sharpening. I know this is a very popular knife, ZT says it is their biggest seller. I have noticed in other forums that recurve owners pretty much stay away from Wicked Edge because they don’t think it will work with their recurves.

I hope Clay reads this and gets the hint to do a YouTube sharpening a ZT350 with the WEPS to attract some of those doubters.

I am excited and a big part of that is being able to share with others who have the same interests, so thanks for that encouragement.

Now, I have a question based on your observations with the flashlight. Is it just the edges of the stone that are sharpening the recurve and if so, won’t that leave deeper microscopic scratches on the blade?

The reason I am asking is because I ordered the WE curved ceramic stones but they only come in 400 and 600 grits which seems limiting. Ideally I would be able to cancel the curved stones and use the full progression of the flat stones but it seems, logically that the recurve and flat stones would not be compatible.

It seems from what I am learning here is that the flat stones would actually work. I was not able to talk to Clay when I ordered the WE System and the person who answered to take the order was not familiar with recurves and suggested I add the curved ceramic stones.

If anyone with a 350 can answer this so I can determine whether or not I need the curved stones could respond, that would be great. The system is not going to ship until at least next week so I can still change it.

Thanks
Scott

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Scott,
I recently sharpened a couple of knives with recurves. I did the CRKT Ken Onion Foresite and the Cold Steel Spartan. The CS Spartan has a more significant recurve. Though I have not handled the 350, looking at the pictures, the Spartan has more recurve than the ZT knife.I just went through my typical progression for working knives. I used 19 degrees per side. The diamonds from 100 to 1000. Then Choseras from 800 to 3000 (I usually stop here with the 1000 Chosera, but decided to make thes a bit finer and more reflective), then leather strops at 6, 3, 1 and 0.05 microns. I then set a micro bevel at 21 degrees with the Shapton 15K stone and restropped at 19 degrees with 0.125 and 0.1 Diamond on Kangaroo. I got nicely sharp and very reflective edges. I didn’t have any problems with using the standard stones and strops.

With the finer stones (2000 and 3000) chosera stones initially there was some flaking of the edges, but I just lightened up the stroke a bit and all was ok.

I didn’t notice any deeper scratches due to hittng the blade with the edges of the stone in the recurve area. I used up to 100X magnification. After all, the sbrasives on the edge of the stone are the same as those in the middle. A nice light touch, it seems, prevents any gouging.

The rounded stones will help getting more abrasive at the edge and maybe speed things up some, But, if you did not have them you should still be able to sharpen the 350 just fine. For setting the bevel, the stock diamonds (from my experience) should work just fine.

Phil

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Thanks Phil,
Very much appreciated :-).

I will call WE Monday to change my order which is cool because now I can add another stone or two that I had a hard time justifying.

It would still be outstanding if others especially with my ZT 350 could share what works what didn’t.

Great community forum this.

Thanks
Scott

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So the curved stones are around the 600 grit range? The ones I got (around the beginning of the year) look EXACTLY like my 1200/1600 grit ceramics that you used to sell… and they perform identically. I use my curved ceramics as an “in-between” to go from the 1k diamonds to my 5k/10k choseras, and they work great. By the time I am off of the fine curved ceramics, I am starting to get a nice polish (Could probably come close to a mirror finish if I were to go to just one strop - i.e. 3um or something).

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[quote quote=“PhilipPasteur” post=4834]Scott,
With the finer stones (2000 and 3000) chosera stones initially there was some flaking of the edges, but I just lightened up the stroke a bit and all was ok.

I didn’t notice any deeper scratches due to hittng the blade with the edges of the stone in the recurve area. I used up to 100X magnification. After all, the sbrasives on the edge of the stone are the same as those in the middle. A nice light touch, it seems, prevents any gouging.

The rounded stones will help getting more abrasive at the edge and maybe speed things up some, But, if you did not have them you should still be able to sharpen the 350 just fine. For setting the bevel, the stock diamonds (from my experience) should work just fine.

Phil[/quote]

If you lap the “corners” or edges of the choseras they will not flake off/scrape off, and also they will not leave any chips in the edge of your knife once they are smoothed out (I learned this the hard way, lol). In fact, I can use the corners of my choseras now to do heavy re-curves just fine… it doesn’t eat them away at all and works great.

+1 on the stock diamonds working on re-curves as well!

Phil, you should post some pics for us for motivation! lol :slight_smile:

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I will try to do that. Got a new camera and trying to figure out how to get postable …decent pictures out of it. The full 18 megapixel photos are way too big… even cropping does not make them of decent size. I will see what I can do this evening.
BTW, I have chamfered the edges on all of the Choseras… maybe not enough. I had to on my 10K… I almost had a heart attack when I chipped one…
:slight_smile:

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Here are a few photos of the Cold Steel Spartan… It has been used a bunch since sharpening. I cut at least 50 suckers off of my Silver Maple tree. Some as big as my little finger (diameter). Have cut cardboard and half inch nylon rope. In other words, it is not a show piece right off of the sharpener with a mirror edge. The knife is a beast !! Just AUS8A, but they must have done a good job with the tempering. It is still pretty darn sharp…at least arm hair shaving sharp. A bit short of push cutting copy paper, but easily slices the same.

Phil

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