CPM REX 45 | Edge Performance

Discuss Spyderco's products and history.
Cycletroll
Member
Posts: 799
Joined: Sun Oct 22, 2017 4:12 pm
Location: North Central New Mexico

Re: CPM REX 45 | Edge Performance

#161

Post by Cycletroll »

I'm wondering if the chipping people are experiencing with Rex 45 is due to having not sharpened the edge enough to get rid of the burnt steel from factory grinding?
R100
Member
Posts: 321
Joined: Thu Oct 15, 2020 5:30 pm

Re: CPM REX 45 | Edge Performance

#162

Post by R100 »

TkoK83Spy wrote:
Thu Oct 21, 2021 7:41 pm
R100 wrote:
Thu Oct 21, 2021 7:30 pm
I am really surprised and disappointed by the accounts of Rex45 chipping. It has put me off a purchase I was considering. I have a number of S30v knives taken back very thin behind the edge and given a 30 degree microbevel. I have not experienced chipping with fairly heavy use unless I hit steel or rock or do something stupid. The only conclusion I can draw from this thread is that Rex45 is a long way behind S30V as an edc steel and I would be crazy to use it. What am I missing?

Dan
I really hope you're joking?? This post is making me twitch.
I am! It was a comment on how fickle we are. I do look forward to trying Rex45 but you can see that reputations hang on a thread in the frenzied world of the internet.

I've never met a bad steel in a Spyderco or had trouble with chipping - even with zdp189 and S110v.

Sorry to give everyone a scare.

Dan
Karl_H
Member
Posts: 157
Joined: Tue May 05, 2020 2:34 pm

Re: CPM REX 45 | Edge Performance

#163

Post by Karl_H »

R100 wrote:
Thu Oct 21, 2021 8:45 pm

I am! It was a comment on how fickle we are. I do look forward to trying Rex45 but you can see that reputations hang on a thread in the frenzied world of the internet.

I've never met a bad steel in a Spyderco or had trouble with chipping - even with zdp189 and S110v.

Sorry to give everyone a scare.

Dan
Are you trying to insult the people that are providing honest reports of chipping?

Would you rather we just said nothing at all or that REX45 is invincible?
Vaugith
Member
Posts: 175
Joined: Mon Feb 08, 2021 9:37 am

Re: CPM REX 45 | Edge Performance

#164

Post by Vaugith »

I get chips in nearly any steel at my job, mostly stripping large wire. I found that on my rex45 burnt orange shaman, freehanding a slightly convex bevel on a muddy king deluxe 1k produces a long lasting edge that doesn't chip at all for me. My top choice for a work knife.

It did chip with a guided system edge at 17 DPS with a 20 DPS microbevel though

All of the folks having issues with chipping - just increase the angle of the bevel or microbevel, just like you would with any other steel. What's so confusing? Or convex it.
GarageBoy
Member
Posts: 2215
Joined: Sun Nov 14, 2004 6:49 pm
Location: Brooklyn NY

Re: CPM REX 45 | Edge Performance

#165

Post by GarageBoy »

Would switching to an all diamond abrasive sharpening regime help with chipping?
User avatar
Paraguy
Member
Posts: 918
Joined: Mon Apr 19, 2021 10:13 am

Re: CPM REX 45 | Edge Performance

#166

Post by Paraguy »

Cycletroll wrote:
Thu Oct 21, 2021 8:31 pm
I'm wondering if the chipping people are experiencing with Rex 45 is due to having not sharpened the edge enough to get rid of the burnt steel from factory grinding?
I doubt Rex edges burn much. It's a heat-retardent steel
"Some call me...Tim?"
User avatar
aaronkb
Member
Posts: 480
Joined: Fri Aug 23, 2019 11:40 am

Re: CPM REX 45 | Edge Performance

#167

Post by aaronkb »

I’ve used Rex 45 a pretty good amount, and I don’t think I’ve ever noticed chipping…. I consider it the most abusable steel I’ve used. I sharpen on DMT diamond stones, if that makes a difference.
User avatar
thewoodpecker
Member
Posts: 495
Joined: Thu Jan 19, 2017 1:58 pm

Re: CPM REX 45 | Edge Performance

#168

Post by thewoodpecker »

Paraguy wrote:
Wed Oct 05, 2022 7:08 pm
Cycletroll wrote:
Thu Oct 21, 2021 8:31 pm
I'm wondering if the chipping people are experiencing with Rex 45 is due to having not sharpened the edge enough to get rid of the burnt steel from factory grinding?
I doubt Rex edges burn much. It's a heat-retardent steel
I think that even though it is a temper resistant tool steel the thin cross-section of a knife blade may still be susceptible to weakening through overheating during the sharpening process. My 0.02¢
Spyderco Caly 3.5 Super Blue user, Astute enthusiast, and geometry advocate.
User avatar
Deadboxhero
Member
Posts: 2146
Joined: Tue Mar 01, 2016 4:35 am
Contact:

Re: CPM REX 45 | Edge Performance

#169

Post by Deadboxhero »

Two years ago I was curious what would happen if I gifted a brand new Spyderco Military model in CPM REX 45, 8% carbide volume, 67.0 HRC and low fracture toughness to a "non knife geek" heavy knife user. This knife has been put through **** it was even left outside in the rain for 2 weeks.

Image

He was an interesting test subject to explore this question because never in his life has he spent more than $50 on a pocket knife and does not care about blade steel so their was no bias from him.

Image


His most used knives were Buck 420HC, I met him when I was a professional knife sharpener and his knives would blunt completely smooth very quickly so I could see objectively his knives were being heavily used and why he checked all the boxes for an excellent candidate to further explore a curiosity.

Image


Well, the knife was put through complete ****, I was surprised it was in one piece, the g10 peel ply is worn smooth so I got a lot of time in the hand from the end user. What was most shocking was that the edge retention was subjectively and objectively better than softer, tougher steels he had experienced.



Without asking leading questions he explicitly stated,

"Yeah that's the best knife I've ever had, just keeps cutting"


Image


He was genuinely stoked about the performance.






Most knives in his use blunted to +1000g on the BESS tester, the softer tougher steels had little resistance to deformity and the edge would smash down in use quickly, I was surprised to see the edge under 500g Bess after the first YEAR.



This knife was only sharpened once when I met him again at Shot Show 2022 in Las Vegas at the Spyderco booth, it was sharpened to 200g BESS with the Spyderco sharpmaker using the diamond rods and finished on the white ceramic.



Its been almost a whole year since it was sharpened and it was nicely maintaining a sub 500g BESS edge with heavy use. NOT +1000g BESS with other steels I've seen from him, so there is real world evidence that the increased cutting edge retention seen in controlled testing does cross over to the reality, the problem is that these steels are expensive and difficult to process, heat treat, and you can't use Grandpa's arkansas stones.





Edge tested 1" from heel
Image

Edge tested 1" from tip
Image



Translation of BESS to paper cutting sharpness


Image





In his perception, if the knife is still physically cutting it is still sharp. What the Rex 45 did was it did not blunt completely smooth at the edge and it could still physically cut without extreme force and slipping compared to a "tougher" softer steel that would have blunted smooth with lots of physical cutting.

Image


Image


The biggest take away I feel for readers is that one should give things a try first hand and see if it works or doesn't work for their preferences and uses.



Image



I'm pretty sure the CPM REX 45s low toughness would be better seen if we duct taped it to a poll and tried to cut a concrete wall in half, but there are probably better and cheaper tools for demolition work.
Big Brown Bear
https://www.youtube.com/user/shawnhouston
Triple B Handmade Knives
skeeg11
Member
Posts: 1478
Joined: Wed Feb 19, 2020 11:45 pm

Re: CPM REX 45 | Edge Performance

#170

Post by skeeg11 »

LUV real world test stuff.
User avatar
Deadboxhero
Member
Posts: 2146
Joined: Tue Mar 01, 2016 4:35 am
Contact:

Re: CPM REX 45 | Edge Performance

#171

Post by Deadboxhero »

skeeg11 wrote:
Thu Dec 01, 2022 2:43 am
LUV real world test stuff.
It is pretty cool, the problem is it's difficult to compare apples to apples without more control seems there could be kind of a paradox in the knife community where controlled testing is not good enough and real world testing is not usable. Yikes.

Of Course realistically they're supposed to go hand in hand.

The problem is it took two years to get this anecdotal real world account.

Given how many steels there are in existence, none of us would live long enough to see testing like this on every steel.
Big Brown Bear
https://www.youtube.com/user/shawnhouston
Triple B Handmade Knives
User avatar
Cl1ff
Member
Posts: 1128
Joined: Fri Sep 13, 2019 4:35 pm
Location: Florida

Re: CPM REX 45 | Edge Performance

#172

Post by Cl1ff »

Deadboxhero wrote:
Thu Dec 01, 2022 2:53 am
skeeg11 wrote:
Thu Dec 01, 2022 2:43 am
LUV real world test stuff.
It is pretty cool, the problem is it's difficult to compare apples to apples without more control seems there could be kind of a paradox in the knife community where controlled testing is not good enough and real world testing is not usable. Yikes.

Of Course realistically they're supposed to go hand in hand.

The problem is it took two years to get this anecdotal real world account.

Given how many steels there are in existence, none of us would live long enough to see testing like this on every steel.
Coming from someone who is seriously interested and invested in paleontology, I am well acquainted with the reality of testing hypotheses. It’s really long term.
That said, the field has advanced extremely quickly in the last few decades and is still picking up the pace. There are a few dozen new dinosaurs named every year and that’s just dinosaurs and just taxonomy. I mean, the evolution of the palate in birds ( it’s more significant than that sounds really) was completely redefined in a study on a prehistoric toothed bird published yesterday and just days before that a new species of dinosaurs similar to Tyrannosaurus was formally published,
and much more.

This advance is caused partly by an expanding body of researchers, but also new technologies, better methods and techniques, and greater public access to knowledge. And all based on long term data collection, passion, and the effort of now many years of collective scientific investigation alongside real world” amateur/professional effort in the field.

All of this is in common with the kind of landscape I think we’re seeing in whatever we’re doing with knives recently. At least, it all feels very familiar to me.

Maybe it’s at a bit smaller scale here, but it’s due to no small endeavor by you, BBB, and other giants in the knife world, like Spyderco, Larrin Thomas, Phil Wilson, Ed Schempp, and more.
rex121 is the king of steel, but nature’s teeth have been cutting for hundreds of millions of years and counting :cool:
User avatar
TkoK83Spy
Member
Posts: 12447
Joined: Mon Sep 17, 2018 5:32 pm
Location: Syracuse, NY

Re: CPM REX 45 | Edge Performance

#173

Post by TkoK83Spy »

Nice to see even more evidence as to why I've found Rex45 to be my favorite steel these past 4 years or so now! I think I give my knives a pretty good run for their money working daily in a warehouse, but that Military there looks like it has some stories! Pretty awesome stuff, thanks for the feedback on that Shawn.
15 :bug-red 's in 10 different steels
1 - Bradford Guardian 3 / Vanadis 4E Wharnie
1 - Monterey Bay Knives Slayback Flipper / ZDP 189
1 - CRK Small Sebenza 31/Macassar Ebony Inlays
1 - CRK Large Inkosi Insingo/ Black Micarta Inlays
1 - CRK Small Sebenza 31 Insingo/Magnacut

-Rick
Wandering_About
Member
Posts: 1384
Joined: Thu Mar 25, 2021 10:06 am
Location: Earth probably?

Re: CPM REX 45 | Edge Performance

#174

Post by Wandering_About »

That's an impressive "test."
Because desolate places allow us to breathe. And most people don't even know they're out of breath.

MNOSD member #0035
Cycletroll
Member
Posts: 799
Joined: Sun Oct 22, 2017 4:12 pm
Location: North Central New Mexico

Re: CPM REX 45 | Edge Performance

#175

Post by Cycletroll »

Thanks Shawn and Cl1ff! It is anecdotes like these that make this group so rewarding!
Shawn, I love that you put your own money and passion into a gift for science that also benefitted an unwitting study participant!
User avatar
Woodpuppy
Member
Posts: 3700
Joined: Wed Jun 27, 2018 6:38 pm
Location: Florida

Re: CPM REX 45 | Edge Performance

#176

Post by Woodpuppy »

If nothing else it appears REX45 doesn’t require any sort of special treatment whatsoever!!! I don’t think M4 would have fared as well, much as I love it.
R100
Member
Posts: 321
Joined: Thu Oct 15, 2020 5:30 pm

Re: CPM REX 45 | Edge Performance

#177

Post by R100 »

Deadboxhero wrote:
Thu Dec 01, 2022 2:53 am
skeeg11 wrote:
Thu Dec 01, 2022 2:43 am
LUV real world test stuff.
It is pretty cool, the problem is it's difficult to compare apples to apples without more control seems there could be kind of a paradox in the knife community where controlled testing is not good enough and real world testing is not usable. Yikes.

Of Course realistically they're supposed to go hand in hand.

The problem is it took two years to get this anecdotal real world account.

Given how many steels there are in existence, none of us would live long enough to see testing like this on every steel.
Great report Shawn! Do you have any idea how an S90V Military may have held up in that situation? Higher edge retention than REX45 but maybe it would be brought undone by lower edge stability due to larger carbides?

Dan
User avatar
Deadboxhero
Member
Posts: 2146
Joined: Tue Mar 01, 2016 4:35 am
Contact:

Re: CPM REX 45 | Edge Performance

#178

Post by Deadboxhero »

Thanks Cl1ff


Cl1ff wrote:
Thu Dec 01, 2022 3:29 am
Deadboxhero wrote:
Thu Dec 01, 2022 2:53 am
skeeg11 wrote:
Thu Dec 01, 2022 2:43 am
LUV real world test stuff.
It is pretty cool, the problem is it's difficult to compare apples to apples without more control seems there could be kind of a paradox in the knife community where controlled testing is not good enough and real world testing is not usable. Yikes.

Of Course realistically they're supposed to go hand in hand.

The problem is it took two years to get this anecdotal real world account.

Given how many steels there are in existence, none of us would live long enough to see testing like this on every steel.
Coming from someone who is seriously interested and invested in paleontology, I am well acquainted with the reality of testing hypotheses. It’s really long term.
That said, the field has advanced extremely quickly in the last few decades and is still picking up the pace. There are a few dozen new dinosaurs named every year and that’s just dinosaurs and just taxonomy. I mean, the evolution of the palate in birds ( it’s more significant than that sounds really) was completely redefined in a study on a prehistoric toothed bird published yesterday and just days before that a new species of dinosaurs similar to Tyrannosaurus was formally published,
and much more.

This advance is caused partly by an expanding body of researchers, but also new technologies, better methods and techniques, and greater public access to knowledge. And all based on long term data collection, passion, and the effort of now many years of collective scientific investigation alongside real world” amateur/professional effort in the field.

All of this is in common with the kind of landscape I think we’re seeing in whatever we’re doing with knives recently. At least, it all feels very familiar to me.

Maybe it’s at a bit smaller scale here, but it’s due to no small endeavor by you, BBB, and other giants in the knife world, like Spyderco, Larrin Thomas, Phil Wilson, Ed Schempp, and more.
Big Brown Bear
https://www.youtube.com/user/shawnhouston
Triple B Handmade Knives
User avatar
Deadboxhero
Member
Posts: 2146
Joined: Tue Mar 01, 2016 4:35 am
Contact:

Re: CPM REX 45 | Edge Performance

#179

Post by Deadboxhero »

Thanks, yeah it's quite surprising how durable it is.


It certainly looks like an antique after only 2 years.

Image

TkoK83Spy wrote:
Thu Dec 01, 2022 6:39 am
Nice to see even more evidence as to why I've found Rex45 to be my favorite steel these past 4 years or so now! I think I give my knives a pretty good run for their money working daily in a warehouse, but that Military there looks like it has some stories! Pretty awesome stuff, thanks for the feedback on that Shawn.
Big Brown Bear
https://www.youtube.com/user/shawnhouston
Triple B Handmade Knives
User avatar
Deadboxhero
Member
Posts: 2146
Joined: Tue Mar 01, 2016 4:35 am
Contact:

Re: CPM REX 45 | Edge Performance

#180

Post by Deadboxhero »

I'm glad it was enjoyed took 2 years to make :D

Wandering_About wrote:
Thu Dec 01, 2022 6:44 am
That's an impressive "test."
Big Brown Bear
https://www.youtube.com/user/shawnhouston
Triple B Handmade Knives
Post Reply