Choosing the correct steel for the job is always the main concern.
The basic 420 grade stainless steel (a grade considered lower than 440a) is known by many to be a lowly quality stainless steel. Even with the best quality controls during heat treating, it simply does not take the sharpest of edges, and tends to easily lose what little it does achieve. What it does do well, is to resist corrosion to a very high degree.
Then there is the common 1095 carbon steel, which is pretty easy to sharpen, sharpens to a nice degree, hardens well, and holds an edge pretty nicely. But,.... unlike the 420 stainless, it must be very carefully maintained to keep corrosion away (not something most divers want to focus on).
So just looking at these two faily common steels, one can see why one may be a better choice over the other (depending on it's intended use).
Lets say one needs a divers knife, the 420 steel requires more often sharpening, will wear down much faster, but,....... will also be very resistant to the salt water and possible maintenance neglect.
A 1095 carbon steel knife will have the better performance in almost all respects, but rust will almost certainly become a problem. The salt water will work itself into unseen areas, and even if you think you have carefully maintained the knife, in no time at all one can end up with a structurally compromised knife. Even the usually achievable sharp edge on 1095 steel is no advantage if that edge consistantly turns to rust.
What if one wants or needs a hard working blade that needs to be sharp, keep that sharpness longer, and just be plain ole stronger. In other words, a knife for general purpose use, and one that will not be exposed to extremely harsh conditions or consistant maintenance neglect, then the advantages of 1095 over 420 become so obvious.
As for the Ka-Bar's 440A stainless, it is not as rust resistant as the basic 420 stainless, but still maintains a very high corrosion resistance, (while in some respects adding a bit of performance advantage over the 420). So does 440a have any place in knifemaking?.... IMO it does.
Again, it all depends on what the knife is being used for, what it will be exposed to, and how it will be maintained.
Going back to the Cutco kitchen knives produced in 440A stainless steel, they surely make for good blades when considering what the blade is being used for. Just imagine what a pain it would be to keep those same knives clean if they were made of 1095 or some other high carbon steel.
Even cutting a block of cheese would consistantly leave rust on your food....... oh, how nice
When you would wash your knives, they would need to be carefully dried, or they would drip rust stains in your kitchen.
The 420, 440a, 440b, steels may be frowned upon by all of the custom knife makers. They may not be favored by many for use under many or most knife conditions, but that does not mean that they have no purpose, or that it's always a bad choice in a knife.
It's a good thing that KaBar offers these utility knives under three different steel grades. The 1095 will fill most persons needs. The D2 is a very good upgrade choice for those looking for not only better edge retention over 1095, but also much better corrosion resistance. Then comes the 440a choice, which loses out in most respects to the other two steels, but gains heavily over them in the corrosion resistance field
All have a place in the large scheme of things
Edited by JimmyJimenez on 09-11-05 03:50.50. Reason for edit: No reason given.