View Full Version : What Rockwell?
What number on the Rockwell scale are we looking for ...... for a good bushcraft knife... Edge holding..... ease to sharpen etc....
I've never forged/made my own blades, but I've been asked.... so I'm asking you lot
Rockwell, or hardness depends on use and some knives actually are differentially tempered. Most knives will have high edge Rockwells @ 58-60. Machetes and axes will have lower Rockwells of @ 54.They have to flex( machete) and absorb inpact ( axe) Military survival knives ,ie MOD4 and USAF have soft Rockwells of 54.They need to be easily resharpened for rough field use. Harder knives are prone to chipping and some can be difficult to sharpen. The high cromium BUCKS are classic examples. Softer knives have poorer sparking qualities as a rule. Many knives are differentially tempered; a soft tang and often spine to absorb impact and a hard edge for cutting. The relatively newer steel types and production techniques are pushing performance beyond the old standards: but this is a rough outline.
There isn't really anything to add to what Chris has already said. About the only thing I can think of is about grain size in the steel.
You can have a hard steel that has large grains that is brittle and breaks easily, then the same steel, brought to the same hardness but with a more refined heat treatment can be much finer grained. This will make it stronger and easier to sharpen. This is particularly true of forged blades.
Places like BladeForums and ckdforums have a ton of info, if you have the time and patience to plough through it all!
I've always taught students to look for a rockwell c of around 55 to 58. This is what Mearsy likes too.
Apart from that read above!
Echo what others have said. A lower rockwell (55-58) will give an easy sharpen edge, but will need more frequent sharpening, while a higher rockwell (58-62) will give a longer lasting edge, but taking far more effort to get sharp. It all depends what you want.
Many who frequently use a working knife, prefer the softer edge. It wont chip as easily, it dulls quickly, but a couple of strokes with a stone or ceramic will get the razor edge back.
Any excuse to stop in between jobs!!
For ease of sharpening in the field, I like 58 or less. But higher can be nice if you are not worried about sharpening under field conditions. Bob Dozier makes knives in the 61-62 range and I know guys who have field dressed over a dozen deer without touching the edge. Also, if you do a lot of woodcarving at home, why bother with the softer steel? I think Mora run around 60 (IIRC) and that gives you a lot of carving time between touch ups. So overall I'd say there's no perfect Rockwell hardness, just different strokes for different folks, eh? :super: