Rc on Spyderco knives

jackknifeh · #1

My understanding is a blade steel has the Rc that the maker wants it to have. It is controlled by the heat treating. Is that correct? I have had two knives with VG-10 at the same time, one Spyderco and one from another company. I used both on the same project (vinyl siding) and the other company's blade got duller a lot faster. So, when buying a knife with blade steel "x" you also need to know the company's Rc if you care about it at all.

So, I wish Spyderco would advertise the Rc of their blade steels on the chart with the "ingredients" and percentages of the steel. Has this been requested before? Maybe Spyderco has a specific reason they don't.

Jack

Ankerson · #2

The Rockwell Hardness (HRC) isn't the only factor in edge retention, it's also how the steels are tempered and if they are CYRO Quenched (Sub Zero).

Spyderco doesn't advertise their HRC numbers because they are always testing and improving, but Sal will and has let us know what they are on certain knives when asked.

But remember it's a range.

Sal really knows his stuff so I would trust him to make the correct choices for best performance in the knives he makes.

Blerv · #3

Agreed. I think often it would lead to people buying higher rated products over ideal treatments or proper applications. People would be skipping steel like S90v for ZDP solely on a number basis.

We have a tendency to think in extremes while living in a world calling for balance. While steel snobs may enjoy a narrow range between ideal and fragile Joe Sixpack needs safety built-in.

jackknifeh · #4

Ankerson wrote:The Rockwell Hardness (HRC) isn't the only factor in edge retention, it's also how the steels are tempered and if they are CYRO Quenched (Sub Zero).

Spyderco doesn't advertise their HRC numbers because they are always testing and improving, but Sal will and has let us know what they are on certain knives when asked.

But remember it's a range.

Sal really knows his stuff so I would trust him to make the correct choices for best performance in the knives he makes.

Ok, that sounds good. Especially about Sal knowing his stuff. No doubts there.

Jack

DeathBySnooSnoo · #5

This is true...Sal definitely knows his stuff, and will tell us sometimes. But...I don't recall ever getting clarification on the GB RC, even though it is probably one of the most talked about hardness questions. Wish that we would though.

gull wing · #6

I agree, Sal performs magic on HT. My Gayle Bradley in M4 cuts like crazy, while another M4 knife of mine (another Mfg), does not cut as well as the GB.

jackknifeh · #7

DeathBySnooSnoo wrote:This is true...Sal definitely knows his stuff, and will tell us sometimes. But...I don't recall ever getting clarification on the GB RC, even though it is probably one of the most talked about hardness questions. Wish that we would though.

I'd like to know the Rc also even though I have let myself be mislead by them. Ankerson said the Rc is only one part of what makes a steel what it is and he knows far more than I do. I bought one steel with high expectations based on the Rc. That steel didn't work for me as well as I hoped. But M4 does work for me and I don't know the number (or exact range). Can I live the rest of my life not knowing the Rc of M4? I think I'll manage. :D

Jack

DeathBySnooSnoo · #8

jackknifeh wrote:I'd like to know the Rc also even though I have let myself be mislead by them. Ankerson said the Rc is only one part of what makes a steel what it is and he knows far more than I do. I bought one steel with high expectations based on the Rc. That steel didn't work for me as well as I hoped. But M4 does work for me and I don't know the number (or exact range). Can I live the rest of my life not knowing the Rc of M4? I think I'll manage. :D

Jack

For sure it is only a part, but I still want to know. The rumour pops up every once and a while about the GB and the RC and it would be nice to just know the truth.

both of my GB are the early ones, and while the odds are that I will never need another, it would be nice to know if I should expect a difference in the performance of the steel.

And it would be nice when the rumour did come up if we could just say look at thread X for the official reply to the rumour.

The Deacon · #9

Think listing RC numbers would raise more questions and cause more problems than not listing them. For one thing, Rockwell numbers are never exact and when you specify a range, no matter how narrow, folks will begin demanding only knives at the high end of the range. Some will even think that because steel A is listed a 62-63 it's automatically better than steel B at 59-60 (or worse, that steel B really should be run as hard as steel A. Some self styled independent tester will be report test results outside the range and imply we're being lied to and cheated. Another self styled expert will claim a higher, or lower, hardness would be better suited.

Blerv · #10

DeathBySnooSnoo wrote:For sure it is only a part, but I still want to know. The rumour pops up every once and a while about the GB and the RC and it would be nice to just know the truth.

both of my GB are the early ones, and while the odds are that I will never need another, it would be nice to know if I should expect a difference in the performance of the steel.

And it would be nice when the rumour did come up if we could just say look at thread X for the official reply to the rumour.

It would be interesting if some people had them tested. It still would represent a narrow range of the sample though and as Ankerson said it's a range.

It's like 5 people dynoing 5 new Corvettes. There could be a 30hp variance which is understandable. The game begins when people trying to figure out which cars are stronger than others and hunting by vin numbers and other strange criteria.

Ankerson · #11

I have one of the older GB's and it's 62.5 HRC.

Ankerson · #12

The Deacon wrote:Think listing RC numbers would raise more questions and cause more problems than not listing them. For one thing, Rockwell numbers are never exact and when you specify a range, no matter how narrow, folks will begin demanding only knives at the high end of the range. Some will even think that because steel A is listed a 62-63 it's automatically better than steel B at 59-60 (or worse, that steel B really should be run as hard as steel A. Some self styled independent tester will be report test results outside the range and imply we're being lied to and cheated. Another self styled expert will claim a higher, or lower, hardness would be better suited.

HRC numbers don't really mean everything as for example S110V at 64 HRC, one blade CYROed and the other not, there will be around a 30% difference in performance in edge retention from the info that I have.

Blerv · #13

Ankerson wrote:I have one of the older GB's and it's 62.5 HRC.

Better edit this Jim! The world will cease to spin and dead birds will drop from the heavens if this news gets out. :D

jackknifeh · #14

Ankerson wrote:I have one of the older GB's and it's 62.5 HRC.

Blerv wrote:Better edit this Jim! The world will cease to spin and dead birds will drop from the heavens if this news gets out. :D

This is terrible! I just threw my GB in the trash. I demand at least 62.7 Rc. I hate low class steel. :D

Jack

md8232 · #15

Does Spyderco Cryo their blades? If not, would it be worthwhile to send some off to Paul Bos to
work his magic?
I have a Mule in S90V arriving today and want it perfect before adding LSCF scales.

Sonny · #16

Blerv wrote: People would be skipping steel like S90v for ZDP solely on a number basis.

That would leave more S90v for me. Hurrah!
Sonny

JLS · #17

Ankerson wrote:HRC numbers don't really mean everything as for example S110V at 64 HRC, one blade CYROed and the other not, there will be around a 30% difference in performance in edge retention from the info that I have.

Exactly. I've run heat treat cycles on mostly D2 tooling and though the print would have a HRC number or range on it, I would ask the project lead what it was getting used for. You can change quite a few variables in a HT cycle and still end up with the same HRC measurement while having different performance in the end product.

Like others, I've had experiences with the same steel alloy heat treated by different companies and have experienced a range of results at the same hardness. Spyderco does an excellent job in giving us near optimum performance while giving some leeway to those who will abuse the blade. It's not an easy dance and the fact that they do it so consistently shows excellent process control.

FWIW, Spyderco used to list HRC numbers in catalogs many years ago. Every knife blade I tested was within the spec listed.

In short, we all like numbers (and I've supplied a number of them on the Mules), but in the end I trust Spyderco to do the HT right. The few times they haven't hit their target, they admit it and do what they can (think ZDP and CruWear Mules).