Grinding and general advice on m390/cpm20cv needed

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Brian.Evans

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I've a customer who wants a small necker in m390. Just to verify, I've seen m390 called cpm20v, but usaknifemaker has cpm20cv. They are the same, right? I'd assume so, but you know what happens when you assume.

The stock is 0.093", and I'm assuming a pain to grind. I'm also assuming, given this steel's abrasion resistance that any finishing after ht is going to be almost nil. I'm planning on taking the bevels down to almost ready to sharpen before heat treat, then basic 240 belt finish afterwards. Does that sound about right? As much as I like hand rubbed finishes, I also like not beating my into a wall for no good reason.

Has anyone used Peter's for this steel? I'm not sure where to send it? Any secrets I should know about it? I'll give Brad a call and ask him too, but I thought maybe you guys could save me some time.

Anyway, I think that's it. I'm sure I'll have more questions later.
 
If it's anywhere close to s90v do as much as you can before h.t. normal belts have almost no effect the only thing that will cut it after h.t. are ceramic belts, and forget about any hand sanding, it gets you absolutely no ware.
 
That's kind of what I figured. I planned on taking it as high as final finish before heat treat, then just clean up the heat treat coloring afterward. Thinking 220 may be the final finish on this one....
 
medicevans said:
Just to verify, I've seen m390 called cpm20v, but usaknifemaker has cpm20cv. They are the same, right?
Click to expand...
M390, CTS-204P & CPM20CV are different alloys made by different companies. The chemical composition is very similar, but the way the steels are made is different. I am not aware of CPM20V.

M390 is made by Bohler Uddeholm who uses third generation particle metallurgy to make the powder for the steel.

CTS-204P is made by Carpenter who uses second generation particle metallurgy to make the powder for the steel.

CPM20CV is made by Crucible who uses first generation particle metallurgy to make the powder for the steel.

The second and third generation PM steels are extremely clean and have additional toughness compared to first generation PM steels.

I have not tested CPM20CV. I have extensively tested M390 and its performance is impressive. At higher hardnesses it is similar to S90V in edge retention, but is much easier to sharpen. I've talked to many knifemakers who have hand rubbed M390 and they say it is easier than S30V.

I recommend Peter's for heat treating. When we first received M390 I called Brad at Peters and asked if he wanted a sample for testing. He said he had been heat treating M390 for more than a decade as injection molding dies. You would have a hard time finding a heat treater who has more experience with this steel.

Chuck
 
Alpha Knife Supply said:
M390, CTS-204P & CPM20CV are different alloys made by different companies. The chemical composition is very similar, but the way the steels are made is different. I am not aware of CPM20V.

M390 is made by Bohler Uddeholm who uses third generation particle metallurgy to make the powder for the steel.

CTS-204P is made by Carpenter who uses second generation particle metallurgy to make the powder for the steel.

CPM20CV is made by Crucible who uses first generation particle metallurgy to make the powder for the steel.

The second and third generation PM steels are extremely clean and have additional toughness compared to first generation PM steels.

I have not tested CPM20CV. I have extensively tested M390 and its performance is impressive. At higher hardnesses it is similar to S90V in edge retention, but is much easier to sharpen. I've talked to many knifemakers who have hand rubbed M390 and they say it is easier than S30V.

I recommend Peter's for heat treating. When we first received M390 I called Brad at Peters and asked if he wanted a sample for testing. He said he had been heat treating M390 for more than a decade as injection molding dies. You would have a hard time finding a heat treater who has more experience with this steel.

Chuck
Click to expand...

Chuck

Do you have any plans to get any M390, CTS-204P or CPM20CV in stock in the near future?
 
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