CPM 4V | Edge Performance

[Deadboxhero]

I'm no stranger to CPM 4V, it's been something I've used and loved for quite sometime. I was introduced to the steel by Jim Ankerson a few years ago. At the time I was the biggest fan of CPM M4, I fell in love with the combination of edge holding, toughness and the killer edge it took.

So back in 2015, I was very skeptical that something could offer improvement over a steel like CPM M4, but as it turns out there is a whole class of steels in the CPM M4 range that offer similar performance but unique attributes such as CPM Cruwear, PD-1, Z-wear, Vanadis 4 extra and CPM 4V.

CPM 4V is a more available USA copy of the European Vanadis 4 Extra. They both offer more toughness and edge stability at a higher working hardnesses then CPM M4, yet reduced edge aggression and wear resistance.

CPM 4V is unique in its potential to be very, very strong,
much more then it's more malleable and tougher cousin, 3V.

CPM 3V will be more prone to edge rolling at the lower cutting geometries then what 4V and M4 can push. Yet, 3v will be a more durable blade then it's higher carbon and vanadium alloy cousins, however so will CPM 1V to 3V etc. So the sweet spot for performance depends more on the application then what is the "best steel."

It's for this reason that 4V and V4E are used for competition choppers over steels like 3v

4v's claim to fame is the Raw strength over the malleablity that 3v can offer at a cost to strength.



If you watch the event, it makes since why competiters select a stronger steel given the geometries and the testing events.

*Here is a video of Dan Keffeler using a Vanadis 4 Extra (same composition as 4V) chopper collaboration with Nathan Carothers*

Guy is a beast

(Most Bladesports competitors use CPM M4, However 4v is catching on and is more available then V4E)






Fast forward to 2018 and we have finally gotten a folder from Spyderco in CPM 4V. The St Nick's Knives Exclusive Para 3.



This is nice since it allows me to really test the steel in the same knives. It's very difficult to isolate the steel from the other variables. Most of the time people are testing geometry more then steel.



The Para 3 has really become a flagship model and thankfully is offered in more varieties of steels which mean it's a great candidate for testing. (Also I love the Para 3 :D )

[The Meat man]

This is going to be a very interesting thread. Thanks Shawn for posting! And BTW I really enjoy your sharpening and testing videos. Keep up the good work! :)

[bwunger]

Staying tuned. So far I'm really liking my 4V Para3. Don't suppose you have any way of testing the hardness? I'm skeptical of St. Nick's claim of 62.5-64.

[Deadboxhero]

I carried and honed the factory edge for week or two until it wasn't responding to Spyderco white ceramic and stropping.




You know when it's time to hit the stones when the edge no longer comes up crisp after a few licks on the white ceramic and the stroping.



Since I had to re-apex on the stone to get that crispy crispy edge it was also time to reprofile and remove the factory bevel scratches and get some fresh steel at the Apex.



Spydercos 4v cut like butter on the CBN 400 grit resin stone. While Spyderco doesn't release the HRC data on their knives I've luckily had a lot of experience with 4v at different hardnesses from 64hrc to 67hrc and there are some unique little quirks you pick up on the material as a sharpener



It's definitely closer to the 60-62hrc side. There was information floating around that it was 62-64hrc





However, that was a misunderstanding of what the spec sheet shows for as quenched hardness values for different Austenizing tempetures. That is not the same as the values after cryo and tempering when the heat treatment is complete.

Not that 4v can't reach that hardness, it's that production companies have to balance the hardness to make it more user friendly to a wider audience.

At 64hrc 4v gets a very glassy feel on ceramic stones, costs more to grind and more whining from lesser experienced users. So while some cry out for more extreme performance the bigger picture calls for more balance. However I do prefer 4v at higher hardeness but it shouldn't ever be a deal breaker for Spyderco fans





The edge was sharpened to a burr and reprofiled on the Green 400 grit BBB "Super Resin" CBN stone

Deburred, consistant finish.

Then to the Burnt Orange 1500 BBB "Super Resin" CBN stone.

Same technique as the 400 grit. Right side until burr, then left side to burr, then reduce and remove on the stone.



I have a huge compliment of stones to select from.

Like anything it's about the right tool for the job.
I like to use CBN/diamond bonded stones because of the volume of Vanadium and other alloy carbide formers.
I feel it gives me a crisper cut to the Apex since the burnishing (rubbing) is reduced and I get more cutting and shaping to the Apex to a finer radius.

However, no magic stone can overcome lack of experience or practice so the priority should be getting some stone time versus buying a bunch of stuff.




I finished the edge with a Naniwa resin bonded diamond 3k to be consistent with the finishes I did with the other Para 3's in CPM Rex 45, CPM M4 and CPM Cruwear.

Lastly, I finished on a leather strop loaded with 1um diamond spray.





The edge did everything I wanted. Mutiple feather curls when applied to a freehanging hair. Nice curvy cuts in paper with no snags.

Came up nicely, very keen

I will say that the 4v is more similar to the M4 in burr removal. It can be a little stubborn compared to Cruwear.
When 4v is at 67hrc the burr breaks off cleaner and is noticably less stubborn and easier to make very, very crisp.


The edge was the least aggressive out of the other tool steels.

M4 being the most aggressive edge, then Cruwear, followed by Rex45 then 4v.

It will be interesting to see how Spyderco's 4v stacks up with more testing.

[crazywednesday]

Will you be chipping brass rods with it?

[Bloke]

Good stuff Shawn, thanks for sharing. :cool:

I’m quite looking forward to the Province and seeing how it performs on our local hardwood. :)

[The Mastiff]

Shawn, Thanks for taking time to write up your experiences and explanations. These are my favorite kinds of threads. Fun to read with stuff for me to learn. :)

Joe

[npad69]

Excellent stuff triple B! Both fun and informative reading your articles and watching your vids.
How suitable is 4V for kitchen use?

[tps3443]

These were only $150! Why did I miss out? I love the colors. They’ve nearly doubled in price. I wish they’d get more in stock.

[Deadboxhero]

Yes, but later

Will you be chipping brass rods with it?

[Deadboxhero]

Thanks Alex, Yea I might have to miss out on the fun, I already spent my province funds, so I'll have to live through you.

Good stuff Shawn, thanks for sharing. :cool:

I’m quite looking forward to the Province and seeing how it performs on our local hardwood. :)

[Deadboxhero]

Shawn, Thanks for taking time to write up your experiences and explanations. These are my favorite kinds of threads. Fun to read with stuff for me to learn. :)

Joe

Thanks Joe, much appreciated, Most of the time I like to keep my observations to myself but I remember when I was learning and how helpful stuff like this is to genuinely curious folks like myself.

[Deadboxhero]

It's very suitable
Although in my opinion, 4v has to be run very hard and very thin to compete with the Japanese stuff.

It doesn't have alot of aggression to play with. It takes a very keen edge but tends to be on the smoother side so it's easier to overpolish and lose that bite on tomato and pepper skin.

However, 4v is alot more durable then japanese steels at similar geometry and high hardeness.
Very chip resistant for what it is.

This is 4v at 64rc with at 0.003" behind the edge of a 15 dps



So you can see you have to tweak the design to the strengthes of the steel to get the most out of it.

The steel alone is nothing without understanding how to synergize it's strengthes over it's weaknesses.

If this knife was 4v at 60hrc and 0.003 bte the edge would not be as impressive; more rolling at the edge.

If the knife 64hrc and 0.015 bte then it would just be too wedgey and also not impressive.

Excellent stuff triple B! Both fun and informative reading your articles and watching your vids.
How suitable is 4V for kitchen use?

[Deadboxhero]

These were only $150! Why did I miss out? I love the colors. They’ve nearly doubled in price. I wish they’d get more in stock.

A whole new world of bonded stones from different brands is coming by the end of the year. Should be fun.

[ferider]

Hey BBB,

thanks for the thread and all the info on 4V and how you grind your new PM.

As I am a proud new owner of two 4V Manix 2, and non Metallurgist, can you please summarize for me the difference between CPM 4V and CPM Rex M4, when both are run at around 64 HRC ?

Obviously the Manix will behave differently from many other knives due to its special geometry, but assume two knives in 4V and M4 have the same geometry, please.

Thanks,

Roland.

[blues]

ferider, Shawn can fill in the gaps, but based upon his prior comments I'd expect him to report that 4V will be tougher but M4 will take a more aggressive edge (at a given finish) and hold it longer.

[A.S.O.K.A]

Staying tuned. So far I'm really liking my 4V Para3. Don't suppose you have any way of testing the hardness? I'm skeptical of St. Nick's claim of 62.5-64.

St. Nick's Knives based those hrc numbers off of the crucible datasheet

[p_atrick]

It's very suitable
Although in my opinion, 4v has to be run very hard and very thin to compete with the Japanese stuff.

[...]

When you say "Japanese stuff" to which steels are you referring? Also, are you comparing the Japanese steels as an equivalent to 4V, or are you talking about Japanese steels traditionally used in a Gyuto?

[Deadboxhero]

It's very suitable
Although in my opinion, 4v has to be run very hard and very thin to compete with the Japanese stuff.

[...]

When you say "Japanese stuff" to which steels are you referring? Also, are you comparing the Japanese steels as an equivalent to 4V, or are you talking about Japanese steels traditionally used in a Gyuto?

Both, I've been using lots of the popular japanese high tech steels in the kitchen, srs 15, hap 40, super blue

And classics like white steel and vg10

As someone that's really into Freehand sharpening with Waterstones I can help but to enjoy japanese steels.

Yet, 4v seems to possess a little more durability.

Don't mean it's invincible or can be used poorly. Just seems to be very resistant to chipping compared to the Japanese steels I've used above.

[Deadboxhero]

I've played with M4 at 63rc and like blues said the aggression went up and it took a nice edge but lost alot of stability and would microchip at low geometries unlike Cruwear and 4v at the same hardness.

Hey BBB,

thanks for the thread and all the info on 4V and how you grind your new PM.

As I am a proud new owner of two 4V Manix 2, and non Metallurgist, can you please summarize for me the difference between CPM 4V and CPM Rex M4, when both are run at around 64 HRC ?

Obviously the Manix will behave differently from many other knives due to its special geometry, but assume two knives in 4V and M4 have the same geometry, please.

Thanks,

Roland.