Carbon Fiber Stretch ZPD 189

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fshaw

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Sep 28, 2006
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I have a Stretch in CF with a ZPD-189 blade. Ergonomically it's a nice knife but I find the edge retention really disappointing for what should be a "super steel." It's not about the sharpening so please no advice there. I have a couple of S30 Blade Techs and an M4 Gayle Bradley and can get them all plenty sharp, the Stretch just doesn't hold an edge anyway near what I was hoping for. I don't find it superior to any of the other knives mentioned in edge retention.

I've read posts where owners send knives out for upgrades in handles, etc., here's my question: Is there a heat treater that I could send this knife out to to get the blade hardness bumped up? William Henry is running their ZPD at R67 although in a laminate. I don't know what Spyderco heat treats their ZPD blades to but this knife seems like it would benefit from a better heat treat. Does anyone have first hand experience doing this? Any danger of blade warpage?

Thanks,

Frank
 
I have no experience with re-heat treating but I've heard of people doing it. Perhaps Phil Wilson would do it? In the case of the CF Stretch I'd recommend selling it because it's discontinued and sells for a premium. Then buy something else.
 
It's a user that I'll keep. I'd just like to get more out of the blade. If a new heat treat isn't feasible I'll use it as is.

Thanks though.

Frank
 
If I remember correctly spyderco heat treats ZDP at 64
 
and even if you dont want to hear it, zdp is a pretty unique steel it needs different care on the stones than s30v and m4. not forgiving at all.
 
Ninety percent of the ZDP-189 edge retention issues I've had personally and read about here have boiled down to sharpening issues. ZDP-189 does not respond the same way S30V or M4 do. Excess pressure will result in a wire edge that quickly breaks off in use, leaving a raggedly flat edge behind. As I recall, when Spyderco tried to re-heat treat the ZDP Mules, it didn't work.
 
What are you cutting with it and how does it dull - edge rolling or chipping?
 
It isn't hard to get it screaming sharp. The tricky part is getting it there ith a durable edge. Good luck.
 
It doesn't chip or edge roll, just kind of goes dull. I don't have jigs so don't know the exact sharpening angle but I'd bet it's between 15 and 20 degrees. There's no sign of edge roll (burr, etc), it just loses it's sharpness faster than I was hoping for.
 
i find zdp the easiest metal to touch up, to be honest. but that my be my method-in-use. i admit it takes longer to profile but i don't get nasty burs like with s30v and vg 10.
 
fshaw, if your issues do not get resolved and decide to sell your ZDP Stretch CF, shoot me an email.Thx.
 
Try re-sharpening and really, really focus on light strokes to avoid a nasty wire edge. ZDP is unlike anything I've encountered. Ultra light strokes are mandatory to get great results that last.
 
FCM415 said:
fshaw, if your issues do not get resolved and decide to sell your ZDP Stretch CF, shoot me an email.Thx.
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Please do not conduct sales/trade/exchange business in the DISCUSSION forums. Especially in a manufacturers own forum. Thank you.
 
Karda said:
Please do not conduct sales/trade/exchange business in the DISCUSSION forums. Especially in a manufacturers own forum. Thank you.
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It was just my own special way of saying that I haven't had any issues with the Stretch's ZDP and I'm such a proponent for it that I'll even take his. I consider it my grail edc, and given the OP's issues nothing gives a higher vote of confidence than for me to want it. I had a feeling I was gonna get policed, my wording was too real. Didn't exactly mean it to be so literal, after all, I could have just PM'd him. I'm not gonna get as creative next time...

I cannot add anything more constructive with the sharpening issues, as so far Ive been touching it up with the higher grit dmt's and mainly stropping with predictably positive results. I would consider ZDP's edge retention a strong point.
 
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You're right, I do not know how to properly sharpen a knife. Now that we have that covered, anyone have any real experience with having a production blade re-heat treated?

Thanks,

Frank
 
Never had a knife re-heat treated, but have had other things that were hard softened and worked on and then re-heat-treated. I do not know much personally, my machine shop took care of it. BTW, you don't have to get an attitude, everyone is just offering up their experiences with the steel, someone on here might actually know more than you about sharpening and in particular ZDP-189 ;). Check out Jim's thread, http://www.bladeforums.com/forums/s...based-on-Edge-Retention-cutting-5-8-quot-rope. Are you in line with what he tested? If not, it could be your sharpening. It definitely is a different steel, and I have not been able to get mine as sharp as brand new. It is the only steel that that is the case. I was a little bummed also that ZDP-189 is not quite super steel status. It stands apart because of high you can run the hardness, not necessarily that it is supreme in edge holding abilities.
 
fshaw said:
the Stretch just doesn't hold an edge anyway near what I was hoping for.
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Here might be the problem. Just what, exactly, were you hoping for?

fshaw said:
It doesn't chip or edge roll, just kind of goes dull. I don't have jigs so don't know the exact sharpening angle but I'd bet it's between 15 and 20 degrees. There's no sign of edge roll (burr, etc), it just loses it's sharpness faster than I was hoping for.
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Here might also be the problem. I know that you say that you have no problems getting it sharp, but keeping ZDP-189 anywhere near 40 degrees inclusive isn't taking advantage of the high hardness afforded by ZDP.

I set my ZDP knives with a 18 degree inclusive bevel and a 25 degree inclusive microbevel. They are very thin behind the edge. Even dull, they still cut well because of the thinness of the bevels.

Keep in mind that if you had a perfectly apexed edge you could have a hair whittling edge at 50-60 degree inclusive. It, however, wouldn't seem to hold a "sharp" edge nearly as long as a 25-30 degree inclusive edge.

If I can get over being lazy, tomorrow I'll see if I can take some pictures of the height of the bevel on my Caly 3.5. You'd be surprised at the size of it, and I've even found that the Caly 3 and 3.5 have a more acute flat grind than the ZDP Stretch.
 
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