Spyderco Forums

Hello all,

I am trying to understand a little bit more about ZDP-189 since I bought a delica a couple days ago with this steel by pure curiosity. I would like to know if Spyderco gets the steel from Hitachi already heat treated or is doing the heat treatment in house. I am asking that because recently Sal said in another post that ZDP is something that Hitachi is really protective of and that in order to process it Spyderco needs to follow certain specs given by Hitachi.

My point is that I am also a fan of Rockstead products and some of their knives are made in ZDP. Are the ZDP from Rockstead and from Spyderco the same finally (except the cosmetic differences of course) in terms of material and process?

Dear Sal, thanks a bunch for making such great products! You kept my interest so high for so many years now! Any chance we could see a PM2 with an ambidextrous locking system like on the Manix 2? I am sure it has practical applications and would also interest some lefties :o

Thank you!

To be clear, all the Spyderco knives past and present, that use ZDP-189 steel are made for Spyderco in Japan. The ones with solid ZDP-189 blades are made for them by one maker, while those with laminated ZDP-189 are made by another maker. Not sure if either, or both, do their own heat treating or, like many US makers, farm out heat treatment to a specialist.

Thank you for your input Deacon!

francoiski wrote: Any chance we could see a PM2 with an ambidextrous locking system like on the Manix 2? I am sure it has practical applications and would also interest some lefties :o

Thank you!

First off, welcome to the forum, francoiski!

About the second part of your question, a bunch of us lefties are requesting a true lefty PM2 (or similar size) in another thread, hopefully you'll find it and join us. Sal seems rather receptive to the idea. The compression lock itself is somewhat close to ambidextrous, but not fully for most. The Manix 2 you mentioned, with it's caged ball bearing lock, is a true ambidextrous gem, for sure!

My thought is that if you're currently looking for blade length around 3.5", require ambidextrousness as a lefty, and seem to really appreciate ZDP-189, definitely check out the current model of the Stretch in British Racing Green FRN. It has really great ergos too, I think you'll like it.

Always happy to hear from another lefty, look forward to your input.

Thank you for your warm welcome Sully!

I am going to read the lefty PM2 thread right away :) The Stretch FRN ZDP seems to be a good choice for me! I will look into it! Over the years there were oh so many great knives I wish were not righty liner locked or compression locked....I completely understand that it is the market that dictates it and this is why I stay with lock backs but it is sometimes so hard to look at those beauties and not be able to bring them back home with me.

Amen, brother! :D

You don't buy steel stock already heat treated, it would be impossible to cut.

I see and it makes sense, so that means that the Spyderco japanese facilities does the heat treatment. But it also means that Rockstead or any other knife maker using ZDP does their heat treatment too. Now the only thing that I am curious about is if Hitachi gives the heat treatment requirements to their buyers or if the zdp buyers just heat treat as they feel like it "should be heat treated".

Thanks for your input Zhyla!

Most of the time there's a recommended heat treat or two depending on application and desired hardness, however, whether they're meant for the simplified production environment or custom I couldn't say.

zhyla wrote:You don't buy steel stock already heat treated, it would be impossible to cut.

He nailed it ^

Hi Francoiski,

Welcome to our forum and thanx for the support and kind words. Some of the q's on this thread will require more time to answer. Have to get back to you.

sal

Sal,

As new owner of ZDP (E4), I'm also interested. If I recall correctly, Rockstead recommended stropping with white compound over denim for maintenance of their ZDP. I also know different HT resulted in different structure, and even rust resistance. It'll affect end product overall performance (rolling, chipping, rust prone or resistance, ease of touch up, etc.)

Recently David/OWE over BF shared about his Kershaw Skyline ZDP tip chipped when stropped although the inclusive angle isn't that low (30° ish). On the other hand, I also recall Jim did his E4 ZDP as low as 20° inclusive, quite sometime back.

Hopefully you have time to share with us Spyderco two different makers' ZDP characteristics so we can 'tweak' the use and maintenance to suit our use case.

Francoiski,

Welcome to the forum and thanks for asking the question

Thank you Cujobob, Zhyla for your inputs! It helps me understand a little bit about how the processing works. Thank you Sal for taking the effort to find the answer!

Thank you for your input and your welcome Anagarika!

I am no expert so please correct me if I am wrong, it seems to me that the Rockstead blades often use a convex grind with their laminated ZDP. I noticed that most of the time, my blades are less prone to chipping with a convex grind (working on deer bones) so maybe that is one of the important factor that makes their blades so durable. In that case 30 degrees instead of 20 degrees on an E4/D4 might help? (even if you have the counterexample with the Skyline) I might feel more "secure" with a 30 degree angle...

It seems to me that Rockstead really got a good knowledge of ZDP, they proved it many times already so it might be good to take their advices when it comes to zdp maintenance. This only works if my D4 and their knives have equivalent ZDP origin and processing at least...that is where my question comes from.

Hitachi trains their heat treaters to heat treat ZDP. Non of the makers, as I understand it, actually do their own heat treat. Hitachi has their "authorized" heat treaters in Japan. As a result of honoring their request, we have had few problems with ZDP and I wold venture to say that Spyderco makes more knives with ZDP than others.

We can purchase any steel that Hitachi makes except ZDP because of their heat treat requirements. So all of our ZDP models are made in Japan by makers that we know use Hitchi's heat treaters.

sal

zhyla wrote:You don't buy steel stock already heat treated, it would be impossible to cut.

These days, most cutting is done with lasers, so cutting is not a problem. The problem is grinding hardened steels. Some are ok but some are too hard.

sal

anagarika wrote: Sal,

As new owner of ZDP (E4), I'm also interested. If I recall correctly, Rockstead recommended stropping with white compound over denim for maintenance of their ZDP. I also know different HT resulted in different structure, and even rust resistance. It'll affect end product overall performance (rolling, chipping, rust prone or resistance, ease of touch up, etc.)

Recently David/OWE over BF shared about his Kershaw Skyline ZDP tip chipped when stropped although the inclusive angle isn't that low (30° ish). On the other hand, I also recall Jim did his E4 ZDP as low as 20° inclusive, quite sometime back.

Hopefully you have time to share with us Spyderco two different makers' ZDP characteristics so we can 'tweak' the use and maintenance to suit our use case.

Francoiski,

Welcome to the forum and thanks for asking the question

I cannot speak for Rockstead, though I know their quality is exceptional. Also, their grinds re hamaguri which works well with stropping. I would guess that eventually they would have to sharpened?

Likewise, I cannot speak for Kershaw's Skyline. Though I would guess they were heat treated in the USA.

I don't know of any special maintenance requirements for ZDP other than, avoid runs and keep it sharp.

sal

Sal,

Thank you for sharing. Good to know Spyderco standard process regarding ZDP :spyder:

I guess with steel like ZDP, if regularly maintained and not letting it dull will prolong the time until it requires sharpening. With my light use, the advantage might not be as obvious as heavy user. Let's see.

Thank you for your answer Sal!

anagarika wrote:Sal,

Thank you for sharing. Good to know Spyderco standard process regarding ZDP :spyder:

I guess with steel like ZDP, if regularly maintained and not letting it dull will prolong the time until it requires sharpening. With my light use, the advantage might not be as obvious as heavy user. Let's see.

Yes, whatever you do, do NOT ever, ever ever ever let ZDP-189 get dull, unless you want to spend non-trivial time and/or money getting it back. For example, I found out that you can re-sharpen it on the medium Sharpmaker rods; you just really don't want to do that.

I have several knives in ZDP (Endura SG, Endura FFG, Stretch CF, Caly 3CF)... The most difficult to sharpen when dulled is Endura SG (combo) due to the amount of metal needed to remove to bring back the sharpness... but FFG models are not so difficult with proper sharpener. ZDP-189 is a fantastic steel in my oppinion... Thanks Sal for so many knives in that steel...