A-2 characteristics.....

[Cliff Stamp]

A two point spread is the best you can offer due to the accuracy of the test blocks used to calibrate the machines.

There are sets of calibration blocks from NIST available which are very precise, they note for example changes of 0.2 HRC in calibration readings compared to blocks from independent sources (even different countries) which have no strict regulatory control (this is on the lower end of the HRC scale for knives, the change is larger for the upper end where most knives are hardened).

NIST of course is pretty much designed for that kind of control being a standards organization. As noted, that kind of very coarse HRC reading allows the steel's properties to change by a significant amount, 70% or more in regards to toughness for example. So it would be more informative to give the actual goal hardness and a tolerance, though you could infer it to be maybe midrage assuming standard form.

Of course it isn't only BR which does this and many companies don't even give hardness readings, ideally they would say how they are doing the hardening which would be informative to the user, but of course there are issues with that as well, specifically competition.

-Cliff

 

[HoB]

In regards to the mini, I like the look of the blade style, is the profile basically full flat or can you see a pronounced curvature, can you measure the edge thickness at 1/8" and 1/4" back? Do you like the finger cutouts in the handle?

-Cliff

I would say it is a full convex to zero edge grind. You can definitely see a curvature running over the entire blade. As you've pointed out, I don't think you gain too much performance with the full convex over a full flat with convex edge, but it definitely adds to the look of the knife. However, I maintain only the edge not the entire blade. But what definitely adds performance is the zero edge grind. Its very nice and accute. Mine actually came with a bit of burr, but once I had it stropped off, it became immediately incredible sharp. Out of the box, this has probably the best edge profile of any knife I own. And yes, I can take my calipers home tonight and profile the edge for you. What you can not see in pictures though is that there is also a very nice "appleseed" shape along the spine. Again not a performance enhencing feature but it definitly adds to the looks. The ergos are great for my hand. The finger choil could probably be a bit rounder to give more security and add a bit of comfort, but it definitely works the way it is and it provides a full hand grip, which is quite important because this is not a "small knife". The spine thickness is a clear testimony to the fact that this was meant to be used for serious work. But even the three finger grip without the choil works well for me. I can wrap my pinky around the "pommel" and get a pretty secure grip on it, but I added a small lanyard loop to improve the 3 finger grip.

Since this turned into a mini review I guess I should add, that on mine the mircarta scales were not entirely evenly ground, which really didn't bother me at all. Gives it a "handmade" feel. The grind of the steel was very even everywhere. And for a $50-60 price tag I think you would be nuts to complain. The sheath is serviceable but not great. I bought an aftermarket Kydex sheath from sagecreekoutfitters: http://www.sagecreekoutfitters.com/...reen=PROD&Product_Code=K7008&Category_Code=BK
and that definitly increased my appreciation for it. I carry it as a neck knife but have a tec-lok for it as well. I just wish now that I would have gotten the black mircarta handles instead of the green mircarta handles to match the sheath .

 

[RJ Martin]

A2 is an excellent steel. I've made close to 1000 knives out of it, and people rave about their performance. The fine grain size is particularly beneficial in the "zero edge thickness" chisel grind. Even though I use a lot of S30V, I still continue to use A2, because some people prefer it.

Because I perform my own heat treatment, and, have the special hardness calibration blocks that Cliff mentioned, I can precisely control the hardness to Rc60, +- less than .5 points. Generally, I hit it exactly. Rc60 is the sweet spot for A2, IMO.

A2 can be sharpened to an unbelieveable state. I have shaved the print off the page of a magazine. I almost cut my finger off on an A2 knife, all I felt was a beesting.

 

[Cliff Stamp]

However, I maintain only the edge not the entire blade.

I used to keep the grind full on the blades until I accidently left one with a small microbevel and did a round of cutting and noticed no loss in cutting ability, I don't do it any more except on really easy to machine steels on blades that never get very blunt like a large custom parang which only cuts wood.

But what definitely adds performance is the zero edge grind.

There is definately a tendancy to overbuild on many knives, possibly due to the tactical mindset, but as others have noted before which is a worse complaint a problem with cutting ability or edge damage, thus makers may tend to err on the side of caution.

A.G. Russell went against this strongly with the Deerhunter and similar designs, edges of 0.005-0.010 and ground at around ten degrees per side. That is a standout design for a light utility knife and I really like the swinger sheath. You can go further with hollow grinds but you start to restrict use.

What you can not see in pictures though is that there is also a very nice "appleseed" shape along the spine.

Reeve does this on his knives, I like it for the ergos, it definately makes a lot of cutting easier.

But even the three finger grip without the choil works well for me.

Extended cutting tends to be problematic for me with partial grips, too much pressure against the side of the finger, if the handle is nice as wide and well shaped it can compensate a long ways though.

And for a $50-60 price tag I think you would be nuts to complain.

Pretty much, similar problems have been noted with other models in regards to fit/finish, but for getting an A2 convex blade for ~$50 with a decent hardening I could live with a few issues.

Rc60 is the sweet spot for A2, IMO.

I would be curious about possibly oil quench + cryo to raise the hardness possibly 1-2 points and tempering between 300-400 to hit the torsional toughness peak and give a very high strength. Ref :

http://www.panix.com/~alvinj/graphA2.jpg

-Cliff

 

[RJ Martin]

Cliff: You need a matching hardness curve for that data to be useful. With my HT process, I live right on that toughness peak.

 

[Cliff Stamp]

Yeah, I have the data for the hardness in table form, not as a graph. The two peaks are 60 and 56 HRC respectively with air / no cryo.

-Cliff

 

[whittet]

I'm really interested in steel choices. I might like a chef's knife that can cut and split firewood but it seems like whatever property you choose to optimise costs you somewhere else so you really have to give some thought to the intended use.

http://www.timken.com/timken_ols/steel/handbook/table.asp

In addition to the properties of the steel there are issues of shape. Some knives want to be small and sharp and hold an edge like a carving tool and others get used like axes and prybars.

Whats the best steel and shape for a blade designed to do one job perfectly as opposed to a steel and shape designed to do every job pretty well?

 

[Cliff Stamp]

Whats the best steel and shape for a blade designed to do one job perfectly ...

Pretty much every steel and shape does one thing really well, the critical part is that thing what you need.

-Cliff

 

[whittet]

I was looking on line and noticed that there seem to be definite sets of characteristics for each style.

I'm wondering which properties just have to be there because its traditional to make a knife that way, which are basically just good engineering and which are artistic license?

Do you always make each knife the way experience has taught you works best or do you try a few things that might not work just to see what happens?

 

[Doug C]

Recently acquired a John Greco Green River in A2 and edge retention is pretty amazing.Plus touch ups are very easy. :thumbup:

 

[Cliff Stamp]

I'm wondering which properties just have to be there because its traditional to make a knife that way, which are basically just good engineering and which are artistic license?

There are a lot of both, even on knives which are made almost specifically for function there are often "artistic" features. The Busse blades for example have "talon" holes which used to have a specific function but now are mainly just trademarks of Busse blades.

Do you always make each knife the way experience has taught you works best or do you try a few things that might not work just to see what happens?

The best makers are constantly evolving, few people will claim that their products are perfect and that they have nothing left to learn.

-Cliff