Spyderco Forums

I'm assuming:

JJ = October 2010
GK = July 2011

Can we get an official confirmation there was a heat treat change between these dates?

Paul said once that it could very well be packing date so while I would assume 9 months or so would be different dates of heat treating a couple letters could be the exact same batch. Even the contrary could happen.

I'm not arguing against the logic above, just trying to derail a game of alphabet soup if it's meaningless. For the longest time I thought the EARLY codes were actually of a higher heat.

The earliest of the early GBs were much harder than they are now from what I've gathered here.

I can't positively say what the problem was with those knives, but there definitely was an issue. M4 has performed VERY well in each of the knives I've gotten after that.

Blerv wrote:I'm assuming:

JJ = October 2010
GK = July 2011

Can we get an official confirmation there was a heat treat change between these dates?

Paul said once that it could very well be packing date so while I would assume 9 months or so would be different dates of heat treating a couple letters could be the exact same batch. Even the contrary could happen.

I'm not arguing against the logic above, just trying to derail a game of alphabet soup if it's meaningless. For the longest time I thought the EARLY codes were actually of a higher heat.

The correct production date is on the blade itself mext to the pivot. it would be interesting to know what dates are on the affected blades or on the JJ and GK knives. Did anyone take it appart and had a look?

CrimsonTideShooter wrote:I ended up selling the two GBs that I made the thread about.

Seems I recall you stating that you traded them both back to the shop that you bought them from, for two new ones. :cool:

MIL-DOT wrote:Seems I recall you stating that you traded them both back to the shop that you bought them from, for two new ones. :cool:

Yep. Pretty much the easiest resolution for me at least, thanks to my awesome local enabler. Haha

Alchemy1 wrote:I have 2 GK's as well. Look on the end of the box w/ the sticker. It will be on there.

Thanks! Mine is a "KK" fwiw.

CrimsonTideShooter wrote:The two new ones are GK. Bought from my local dealer right after he got them in a a couple months ago. :)

Mine is also GK (on the box), but mine is an under-achiever

Do we have anything more than a guess that the heat treat and final hardness was in fact changed ?

I don't recall anything official. Does anybody?

I have first run or batch GB, and some with JJ markings on the box. The JJ has been a safe queen so I don't have any performance comparisons to make.

This idea of a changed heat treat came from one guy having problems with his knife and , what?

Is it CTS? Our CTS from the S35VN rolling incident?

Am I getting things and people confused?

Joe

Mine has a date code of JA but I have no idea what that means. My knife is perfect though.

@Joe
Multiple people across batches have been having issues, so not just CTS of the infamous S35VN test has experienced it. Lets stay on topic though.

For the purposes of this diagnosis what if we assume that everyone who has said something is in fact correct. We should not twist facts to suit theories, rather theories to suit facts, ergo we need something all encompassing and preferably falsifiable since we do have a user who currently has a knife with a problem.

The facts:
-edge deformation and rapid dulling is present in several knives across batches
-not all knives, dare I say most knives, perform exceptionally well so this problem is relatively isolated
-one user sent a problemed knife back to Spyderco for testing
-in spyderco's testing no problems were found. Hardness at the spine and on/behind? the bevel were to spec and a CATRA test produced a pass
-on none of these knives is there any visible heat treat damage from applying the original edge bevel
-we are unaware of any similar issues occurring with any other model knives out of Taichung

theory assumptions
-damage to the heat treat at the edge would be visible from the factory, and likely would have been pulled out during QC
-blades are not stamped out of steel stock, likely they are laser cut


My theory? We need something that allows for the issue to be present at one point in time but disappear at a later point in time. We also need a theory which excludes the possibility of a bad heat treat since our sample size of one clearly indicates that was not the case. My theory is that cutting a steel with a laser damages the steel at the edge, we know this, and this damage is both irreversible and is a certain (shallow) depth. On the GB that laser cutting damage is ground off around all the sides, mainly to improve the overall fit and finish, but time is money and so likely wouldn't be ground off at the edge, the bevel would just be applied. Normally this isn't an issue because when applying the edge bevel the apex will sit back from the edge of the blank. On this particular day the worker was particularly quick and industrious and didn't waste extra steel at the edge, and instead left the apex quite close to the original surface and in the damaged steel. When the user then got the knife the damaged steel clearly wouldn't hold an edge and experienced the problems described. Spyderco, upon getting the knife, first rockwell tested it and confirmed hardness just behind the apex and at the spine, and then put a fresh edge on it for CATRA testing. This fresh edge was very likely applied with the same power tools used to apply the original bevels on models out of the SFO because there was evident edge damage. The result was removal of the damaged steel leaving properly hardened steel at the apex. The knife then proceeded to perform well on the CATRA test leaving everyone scratching their heads as to what the problem was.

What do people think? I would very much appreciate it if someone from Spyderco would weigh in and tell me just how big a pinhead I am.

I doubt it's the steel Spyderco got nor the heat treat they used. Cruware as case in point. Spyderco would have had a recall on the defective gb's. Must be some human error as that's the only consistent factor I can think of.


Unless, someone along the way switched the steel that was used?

The Mastiff, no one is saying the heat treat changed for sure. I said it was a possibility, and followed it up by saying that it was just conjecture since I never sent the knives in.

I have two VERY well performing GB's now, so I don't really have any say in this anymore.

Bluntrauma wrote:Mine has a date code of JA but I have no idea what that means. My knife is perfect though.

This means your knife was made manufactured in October 2001. The 2 letters are a code for date of manufacture

CrimsonTideShooter wrote:The Mastiff, no one is saying the heat treat changed for sure. I said it was a possibility, and followed it up by saying that it was just conjecture since I never sent the knives in.

I have two VERY well performing GB's now, so I don't really have any say in this anymore.

What are your date codes now?

Mine is GK but I have not used it yet, so I cannot determine if there are any issues. Truthfully; I do not even know enough to probably even tell

Mine are GK as well.

Yea Joe. No official word just independant testers.

I hate to be the one seen as putting my head in the sand but unless there is official word of a change I'm going to disregard this. Otherwise I have to think all runs of all steels (except H1 I guess) vary depending on the weather by a noticeable degree.

As Cliff said once there is always variance among blades tested. Thinking about avoiding certain dates puts my paranoid micromanaging to the test. Still, having a GB able to take a nice edge and minimize microchipping isn't a bad thing, it's kinda the point of the knife.

INFRNL wrote:This means your knife was made manufactured in October 2001. The 2 letters are a code for date of manufacture



What are your date codes now?

Mine is GK but I have not used it yet, so I cannot determine if there are any issues. Truthfully; I do not even know enough to probably even tell

**** I must have dyslexia. When I looked at your message I realized the knife wasn't made in 01 and went back and checked. It's AJ. *slaps self in forehead*

Mine is JJ, and I can say that I did find evidence of surface decarb. In fact, I can scratch glass with some sections of the edge (I know, this rolls like **** and is murder to the edge). It was puzzeling that some sections cut into the glass, while others simply deformed and didn't touch the glass. About 60% was hard enough or had carbides enough to damage glass. Then I took it to my grinder and resharpened it to a finer angle with a trizact belt, making sure i raised an even bur an either side (ex-knifemaker...).
Back to the glass test, lo and behold, now 100% of the cutting edge scratches glass. Resharpen again, back in the pocket.

My 2 cents, surface decarburization. Either put a few pieces of cockes in the heat treating oven ( to burn up the O2), or increase the argon pressure, or grind more off the blades after ht'ing.

CrimsonTideShooter wrote:Mine are GK as well.

Nice! I should be good to go as well :D

Bluntrauma wrote:**** I must have dyslexia. When I looked at your message I realized the knife wasn't made in 01 and went back and checked. It's AJ. *slaps self in forehead*

I was thinking that but didn't post the other way. My Dyslexia get worse eveyrday I get older :o

So your knife was manufactured in January of 2010. The Deacon has a link explaining the date code in good detail, check it out Date Code Explained

He has some other great stuff, find his links in his sig

INFRNL wrote:Nice! I should be good to go as well :D



I was thinking that but didn't post the other way. My Dyslexia get worse eveyrday I get older :o

So your knife was manufactured in January of 2010. The Deacon has a link explaining the date code in good detail, check it out Date Code Explained

He has some other great stuff, find his links in his sig

Thanks for the link. Lots of good information. Appreciate it!

For what it's worth, having disassembled knives with dates on the tang, the date code on the box often does not agree exactly with the date of the blade. Actually, neither date necessarily indicates the date of the knife itself, only the dates of the blade and the box. :)