S90V vs K390. Makes no sense

[LostCause]

First, Manly’s website specs the S90V City at 60-62 HRC, so that’s the range I would consider accurate. Per Sal, “K390 runs about 64.” So, the specs are closer than you thought.

Second, it’s generally accepted that you don’t get a true representation of a steel’s edge retention until you’ve sharpened the knife a few times to get past the factory edge. Pretty much every factory edge is machine ground and “burnt” to some degree.

Third, Larrin’s testing had S90V at 61.5ish HRC out-cut K390 at 63ish HRC by about 7%. So I think it’s safe to say that your experience is not necessarily unexpected or unprecedented. Carbide type/hardness and carbide volume are very influential for edge retention, and I believe S90V has higher carbide volume than K390. This would also track with K390 having significantly higher toughness.

Hardness possibly being S90V at 62 and K390 at 63 would explain a lot.

Neither of them taking damage from hitting a staple could be due to grind differences or it just means both have respectable toughness.

I did sharpen S90V out of the box and before test.
K390 was sharpened a lot more before I tested it on carpet and so on...

S90V having higher carbide volume would also explain why it resists sharpening more than K390.

 

[sharp_edge]

I like S90V very much. I've been using a Benchmade 535-3 (cf scales, S90V blade) for most of my EDC tasks. I sold all my K390 knives (police, Endela, delica).

 

[Grasshopperglock]

Never owned K390 but I've sharpened a number of s90v.

It's remarkably more easy to sharpen then Buck 420.

It has a powder feeling. Takes a decent edge.

I wouldn't call it a hard steel. Not like that 3CR13 I recently did.

 

[pvicenzi]

Many rate edge geometry as the main factor influencing performance. Heat treating is generally thought to be the second most important factor. Type of steel is third. This is why Buck's lowly 420 competes well with more exotic steels.

 

[OrangeBlueOrangeBlue]

Many rate edge geometry as the main factor influencing performance. Heat treating is generally thought to be the second most important factor. Type of steel is third. This is why Buck's lowly 420 competes well with more exotic steels.

Maybe if your idea of “exotic” is AEB-L or Nitro-V. Even 440C and VG10 do way better than Bos 420HC.

 

[LostCause]

I like S90V very much. I've been using a Benchmade 535-3 (cf scales, S90V blade) for most of my EDC tasks. I sold all my K390 knives (police, Endela, delica).

I heard about S90V years ago and I never thought I'd like it. Now I have it and it's becoming my favorite.

 

[Smaug]

Many rate edge geometry as the main factor influencing performance. Heat treating is generally thought to be the second most important factor. Type of steel is third. This is why Buck's lowly 420 competes well with more exotic steels.

This is often repeated here, but I have not found it to be the case, except that it is lowly.