Re: K390 PM2 | Testing
Posted: Fri Nov 22, 2019 11:03 am
Thanks so much for all this info in terms a layperson can understand! Very interesting and helpful.Deadboxhero wrote: ↑Fri Nov 22, 2019 10:45 amIt doesn't work that simple,
Rex 45 has ~8% total carbide volume in the matrix. It's 2.5% vanadium Carbides plus ~5.5% Softer M6C Tungsten Molybdenum rich Carbides.
K390 has ~16-17% volume Vanadium carbides in the matrix.
So, that k390 edge will resist being worn down and blunted smooth from lots of cutting.
The rex 45 matrix may be harder but the K390 is still more wear resistant and will cut longer.
Rex 45 is fun for how hard it is from a production company. Really enjoy the keen edge holding it offers and can drop angles lower with great stability and how easy it is to shape the apex to a very keen edge since we don't have to cut and shape as many very hard carbides.
It's crazy that we have Hap40/Rex45 in a production folder. Gotta love that "voodoo steel"
Softer K390 still has more edge aggression.
At 63.5rc, the k390 edge has what I call a "Cruwear" effect meaning it's sharpenablity is very high, I've been talking with Michael Christy about his thoughts on the Pm2 k390 edge character, I feel we both agree, it's interesting to see that sticky edge Cruwear effect at 63-64 but with the aggression of k390 it makes for a nice edge character that's fun to play with.
Larrin Thomas was flexing his Heat treatment skills and he Heat treated a K390 test knife at 68rc. I still need to test, it is impressive seeing what the maximum limit is for k390, there isn't any data for that though so no one knows what that edge is like and it is horrendous to grind so not realistic for making knives at high volume.
When the matrix is harder with hard carbides inside at high volume, it's a nightmare to grind and the abrasive cost goes through the roof, that's why it's so neat that Spyderco makes Maxamet so available, they deserve a great deal of respect for that.
About the Cruwear, I run the Cruwear softer in my customs because I like how that edge comes up in Cruwear at 62-63rc. Cruwear is capable of 65rc but it was encroaching on CPM 4v's territory and cruwear doesn't have the firepower of 4v. So, I felt the benifit to Cruwear was the edge character and sharpenablity, so I kept lower for that sticky edge that comes up easy with a variety of different stones.