Rockwell 50: " The magic Number"

[Josey Wales]

For some time now I have been interested in the making of knives... So far I have been able to find the time to make one, now I would like to make one form scratch. I would like to make my own blade.

I Have been offered the possibility of borrowing a furnace e.t.c. and would like to make a bushcraft style blade resembling the woodlore rather than its alternatives (it has quite an aggressive shape) so I have two questions:

1) how do you heat treat something to such a precise measurement as Rockwell 59?

2) Could anyone who has a woodlore get in touch about the shape/ dimensions etc?

I realise that what I am asking for is quite a tall order so I will not be too offended if you decide to give this thread a miss , but this seems to be a bit of a shady area. Any replies will be greatly appreciated.

Cheers,

 

[risby]

For some time now I have been interested in the making of knives... So far I have been able to find the time to make one, now I would like to make one form scratch. I would like to make my own blade.

I see that you are a member of BritishBlades. I guess you might get a more informed response to this sort of question over there.

[not to undervalue the knowledge and experience of many members here, of course]

 

[Lord Farquhar]

The RC is defined by :

1 the steel
2 the hardening
3 the tempering

most common tool steels the RC can be worked out if you have controll of the tempreture.

whats steel are you planning to use?

 

[Josey Wales]

I was thinking of using O1 Tool steel - unless you recomend something else

cheers

 

[Keith_Beef]

1) how do you heat treat something to such a precise measurement as Rockwell 59?

Depending on your steel, you could find that you have quite a wide margin of temperatures for hardening and tempering, which will give you a narrow range of final hardness values.

Very often, hardness will be stated as being in a range; for example 57 - 59 HRc.

Only after testing can you stat that the piece is a specific hardness.

And if you want to get really picky, that hardness can only be guaranteed for the very spot where the test was carried out.

And then if you have a piece with varying thickness over its length (like a blade), that hardness is sure to vary...

And if you have an edge quench, or differential temper, even more so...

All this measured on a scale with useful values (as far as knife blades are concerned) that has only about eight points; 56 HRc being around the softest to 62HRc being around the hardest.

With some steels, you can go higher, though higher hardness is usually associated with less toughness and higher brittleness; not what you want in a bushcraft-type blade. It is probably wiser to have a tougher, less hard blade that is easier to sharpen (even if it blunts more quickly), and less likely to break under hard use.


K.

 

[addyb]

I think generally, anywhere between say, a 56hrc to a 58 or 59 is perfect for a general purpose blade. Some people say that 56 is too soft, but for an SAK or a Leatherman or anything else in that EDC category, it's perfect. A little bit of a convex edge bevel and you're good to go.

For a medium length fixed blade like a Frosts Clipper or anything along those lines, I think 58 or 59 is fantastic. Not too hard that the blade will chip during heavy use and not too soft that you'll have to steel it every ten minutes.

As you said Josey, "The Magic Number," but one still has to factor in blade shape and grind, and even the handle or clasp. There's no easy answer, and it took me a looooong time to realize that.

Just my $0.02 cents,

Adam