Spyderco Forums

ferider wrote: ↑

Mon Jul 01, 2019 6:58 am

Pelagic wrote: ↑

Wed Jun 19, 2019 7:39 am

Naperville wrote: ↑

Tue Jun 18, 2019 7:57 pm

https://youtu.be/Y68yJfGDVg4

That pretty much sums it up. LTK and the people in his group are doing a huge service to the community.
No one is claiming HRC is everything. Like LTK said, you CAN have bad cut tests results with high hardness. But acting like HRC is irrelevant is beyond disingenuous. While Buck pretty much nails their HT on 420HC, there's no excuse for it outperforming ANY M390 in any blade.

Just for the records here on the Spyderco forum, it’s instructive to see how CollectorKnives followed up on LTK’s reporting low HRC Lionsteel knives with a 3rd party verification witnessed by the tester quoted by LTK, how this tester took down his Instagram account, and how LTK has yet to respond:
Production M390 - Expectation vs Reality?

curlyhairedboy wrote: ↑

Fri Jun 28, 2019 9:52 am

if i remember correctly crucible's recommended range is 56-59, so while I'm sure that custom makers can take this well into the 60s, on a hard-use knife like the shaman, I appreciate having at least the manufacturer-rated impact toughness.

So for S90V Crucible’s HRC recommendation matters (for improved toughness), but for CPM-20CV it doesn’t ?

Roland.

Here are notes to add context to the CK response.

1. Tester arranged third party verification with the lead at Peters blade division.

2. They discussed methodology and equipment, and confirmed that each were as they should be.

3. They tested the Dom, which didn’t match prior hits. They retested it to confirm.

4. Per the CK writing, they also tested a previously untested Lionsteel sample. Result was as described.

5. They tested multiple other previously tested, non-Lionsteel samples, and confirmed matching results on each.

6. In light of one anomalous sample, multiple confirmed results, and having level set on methodology, equipment, maintenance standards, calibration, etc, they were unable to collectively determine why the Dom hits were off, and concluded that further exploration of the sample was in order.

7. Our guy and the gent from Peters parted as friends, and may get together on verification again in the future.

The deletion of social media accounts is for work discretion reasons, not integrity issues.

LTK has a response coming.

The doc is updated with Peters hits on the two Lionsteel samples they hit.

Thanks for summarizing for us, B247.

BTW, just for my education, how does a Rockwell tester get calibrated ?

ferider wrote: ↑

Mon Jul 01, 2019 9:14 am

BTW, just for my education, how does a Rockwell tester get calibrated ?

They buy a known hardness block from the maker that is certified and use that to calibrate it.

Sometimes they need to have the maker come out and do it.

Thx

Common Problems in Rockwell Hardness Testing (pdf download)
Heat Treating Progress May/June 2004

https://www.google.com/url?sa=t&rct=j&q ... rYacVBBMrp

Roman of KASE Knives Switzerland posted a video today discussing HRC AND other variables to consider in regard to knife performance.

I found my s90v 64+rc edge quite stable. otoh, I don't disagree with your statement when referring to outcome of standard ht protocol.

https://youtu.be/SNtBP8XB-e8

Ankerson wrote: ↑

Fri Jun 28, 2019 10:13 am

Pelagic wrote: ↑

Fri Jun 28, 2019 10:08 am

I'm aware. S90v is more geared for performance though. If I was to buy a custom I'd prefer it higher.

60-61 is about the max for S90V even in customs depending on the batch and who is doing the heat treating.

S90V doesn't do well at the higher hardness, it gets pretty chippy… So 59-60ish is pretty solid...

S110V is MUCH better in that regard, can be taken to ~64...