K390 steel

[Rsq]

I have two questions about this steel

1. I am going to use this for a tanto style knife, what is the maximum length (including tang) that is recommendable, before it becomes brittle? Ideally, I would like something in the 16" range, but I want to make sure that this isn't too large.

2. This is a bit of a stretch, but I have read that this can take a great edge. I have been experimenting with straight razors, which is a pretty extreme test of a steel. I know that this is supposed to have a reasonably fine grain, given 3rd gen bohler pm tech, but at 9% vanadium, will it take a straight razor edge?

 

[mete]

What length it becomes brittle ?? Whatever the properties it will be the same regardless of length !
This is a powder steel and very high quality. However it's a specialty steel not what I would recommend for razors. The very high carbon and vanadium content would make grinding and sharpening a challenge.
There have been recent threads about razor steels , read those and pick one of the ones recommended !!

 

[Rsq]

A lot of those razor threads were mine
I recently found out about this steel, and it has properties I find intriguing. The difficulty of sharpening doesnt concern me, the razor would be for me.

By what length does it become brittle I meant what length would the brittleness become a problem. If you do light chopping with a 4" blade ground to .025 behind the edge, there is very little worry about brittleness, in any steel. If you're talking about a 10" blade ground to .010 behind the edge, then it is an entirely different ball game. I was wondering about the outside extreme dimensions that k390 would remain stable.

Please note that I am talking about making a knife meant to be used as a knife, I would never expext this steel to stand up to egregious abuse like prying, but light abuse like chopping instead of slicing, that is what I'm wondering about.

 

[OTK]

I would think this steel would not be good for a straight razor. It tends to be a very aggressive edge but it may work out. Sharpening and grinding won't be fun. Try and let us know.

The strength of this steel is that it can be run very hard (63-64) and still be tough enough to use a very thin edge. That being said, if you want to chop use something else. This is just my opinion and this is a pretty new material but I have made several from k390. It is probably my favorite steel.