Thank you for the recommendations. I guess I was a bit hesitant about the Spyderco because of the CTS-XHP steel. The rankings place it at the same edge retention as the M390, but for whatever reason, I have seen multiple comments on the M390 edge lasting much longer than the XHP and that the XHP is very close to the S30V or even the D2. Hence the confusion.
The S110V is rated to have the best edge retention, but it's also ranked as one of the least tough steels, less so than AUS 8, so I have steered away from it. I want to be able to use the knife as needed without worrying about ruining a $200-$300 knife. Though in reality, I don't really understand the real world difference between a Toughness ranking of 2 (S110V) vs 6 (XHP).
This was an excellent observation about blade geometry, something I did not even consider. You're right, that could make quite a difference, assuming that a thinner geometry doesn't also mean more fragile blade. As for the ergonomics of the handle, I guess I won't find out until I receive it. One of the unfortunate side effects of ordering online...
Imagine toughness as the amount of stress a blade can take without chipping, or even how much it could bend without breaking.
The difference is incredible. S110V can often withstand only a few foot pounds of force applied to it, while XHP might hold up to five or six times more pretty easily.
M390, CPM-20CV, and CTS-204P are actually identical steels produced by different companies under different names. CTS-204P is rarer than the other two, and is produced in America by Carpenter, which lends to the illusion of higher price.
M390 is made by Bohler in Austria and is probably the most common of the trio.
For what you want to do, M390, XHP, M4, or even S35VN will all work great. In practice, you probably wouldn’t ever be able to tell the difference between these steels if they were on the same knife!
Basically:
M390 holds an edge very well and doesn’t rust easily. Not super tough, but pretty good. Avoid metal staples.
XHP is the toughest of the crew, but holds the least edge. Still pretty good edge retention.
M4 is very tough and holds a great edge too. Not as tough as XHP, and not for as long as M390, but very good scores in both categories. It rusts easier.
S35VN holds a good edge, is pretty tough, doesn’t rust easily, and is pretty good to sharpen too. It’s the most balanced of these steels.
The guys up there are right though—the shape of your knife is a big deal!
For cutting cardboard, I’d go with the Chaparral. I might not buy it personally, but for what you want to do, it’s great!
(As long as it fits your hand!)
If you really want to get into the science of it, look up Knife Steel Nerds or search for “Knife Steel Nerds” plus whatever you’d like to know about the steels.
