What hardness is Buck's BG-42?

Carl64 · Nov 22, 2005

I would think I had asked this before, but poking around I notice that this page says 60-62:
http://www.buckknives.com/technical_steel.php

But this page about Bos and Buck says it's the same as ATS34 and s30v (59.5-61):
http://www.buckknives.com/technical_making.php

I would hope my knife from the custom shop is 60-62 to take advantage of BG42 being supposedly so great (I have seen high hardness suggested for it elsewhere).

SteelDriver · Nov 22, 2005

Rockwell C ratings usually have a tolerance of +/- 1. That's why you often see ranges for these hardness such as 57-59, 58-60, 60-62, and so forth.

Honestly the difference is so small that you probably could not tell even with the Rockwell tester (because the ranges overlap so much), let alone with use.

Carl64 · Nov 22, 2005

One point matters. 90% of the knives any of us are interested in are between 56 and 60, the the hardness, as well as other things, is very much noticable.

In addition to the actual hardness indicated by the rockwell number, different steels have different ideal hardness levels to improve other characteristics. I don't know what BG42 would be like with the variation in question, but I am not going to assume that 59-61 vs. 60-62 will not be significant when it very well might.

Mike Kerins · Nov 22, 2005

I think there is a danger in looking at the sharpness characters in isolation. I've seen it mentioned that the ideal hardness for S30V for example is 57-59. I imagine it is because of the overall qualities of hardness, brittleness, and ability to sharpen that are considered in that assessment. I'd be willing to give up a couple of Rockwell numbers if the knife is a little easier to sharpen. I think that is what makes S30V better than BG-42. If I'm wrong, please someone correct me!

gaj999 · Nov 22, 2005

Mike Kerins said:
I think there is a danger in looking at the sharpness characters in isolation. I've seen it mentioned that the ideal hardness for S30V for example is 57-59. I imagine it is because of the overall qualities of hardness, brittleness, and ability to sharpen that are considered in that assessment. I'd be willing to give up a couple of Rockwell numbers if the knife is a little easier to sharpen. I think that is what makes S30V better than BG-42. If I'm wrong, please someone correct me!

You're right. Steel, hardness, edge geometry, and intended use all play together. That's why there's no "best" steel/knife. A smallish blade intended for cutting, as opposed to chopping/prying/other abuse, benefits from a thin profile and high hardness. RC 62 for BG-42 is good, 63/64 for 1095 is good. Most manufacturers run their blades softer than optimum as well as thicker than needed for the intended use. They do this to reduce warrantee costs, since many of their customers will abuse their products and then send them in for replacement. (Thick blades seem to be stylish right now, as well.) I'd do the same thing if I was mass producing knives, so I'm not casting stones, just expressing frustration. One of the advantages of S30V compared to S90V or BG-42 touted to manufacturers is it's machinability = tools last longer = lower production cost = lower price or higher profit. It is a good steel, it may or may not be the best for your application. As to sharpening - a good profile and good technique allows easy sharpening of the hardest steels.

Gordon

guy g · Nov 23, 2005

Carl, I had a 532 tested and it was 61. Hope this helps.

rhino · Nov 24, 2005

Is the Rockwell C scale linear? Logarithmic? Something else?

Carl64 · Nov 24, 2005

guy g said:
Carl, I had a 532 tested and it was 61. Hope this helps.

Thanks.

I actually transferred the info wrong in the first post, the website says 61-62, not 60-62.

DarrylS · Nov 24, 2005

rhino said:
Is the Rockwell C scale linear? Logarithmic? Something else?

Actually, the Rockwell "C" scale is linear in that it records the position of the shaft, thereby measuring the indentation depth and the spring force applied at one time. To measure the hardness of metal, Rockwell measures resistance to penetration and that depth of penetration is recorded and is usually directly read from an indicator or scale on the machine. What it is , is actually a glorified depth gage. Some other methods measure the diameter of the indentation rather than the depth, but they are for the softer more malleable materials. I should add that it is the measurement method that is linear. The actual differences between hardness numbers are not. Those figures are determined by very complicated formulas that have long ago left my somewhat limited memory. (Age does "creep up" doesn't it?...LOL)

pens1fan · Dec 15, 2005

I've seen the topic of BG42 several times in the forums. The material data sheet can be found on Timken- Specialty Steel web site:
http://www.timken.com/products/specialtysteel/engineering/tech_info/knifesteels.asp

To take advantage of the "higher alloy content" The grade should be 60-62 Rockwell. As far as grinding it... higher wear resitance is the result of hard carbides in a hard structure. The sharpening process is just accelerated wear... so it follows if you have increase wear resiatance you will also have something more difficult to grind.

rhino · Dec 15, 2005

Thanks for the info. My age is creeping too ... and I've purposely tried to forget all scientific, technical, and mathematical knowledge I gained prior to 1994. The stuff I learned in materials science and physical chem classes falls into that category!

DarrylS said:
Actually, the Rockwell "C" scale is linear in that it records the position of the shaft, thereby measuring the indentation depth and the spring force applied at one time. To measure the hardness of metal, Rockwell measures resistance to penetration and that depth of penetration is recorded and is usually directly read from an indicator or scale on the machine. What it is , is actually a glorified depth gage. Some other methods measure the diameter of the indentation rather than the depth, but they are for the softer more malleable materials. I should add that it is the measurement method that is linear. The actual differences between hardness numbers are not. Those figures are determined by very complicated formulas that have long ago left my somewhat limited memory. (Age does "creep up" doesn't it?...LOL)

Carl64 · Dec 16, 2005

pens1fan said:
I've seen the topic of BG42 several times in the forums. The material data sheet can be found on Timken- Specialty Steel web site:
http://www.timken.com/products/specialtysteel/engineering/tech_info/knifesteels.asp

To take advantage of the "higher alloy content" The grade should be 60-62 Rockwell. As far as grinding it... higher wear resitance is the result of hard carbides in a hard structure. The sharpening process is just accelerated wear... so it follows if you have increase wear resiatance you will also have something more difficult to grind.

Thanks for the info. It looks like the small burr tendency isn't going to go away if BG42 is really that much more wear resistant than 440c. I was hoping the high hardness would help out on that, but it might just barely be making up for the increased wear resistance.

I still like it better than most other stainless steels so far. It has basically the same sharpening behavior but all-around better performance. The burr from sharpening is smaller than usual and slower to form under use. Of course, if it improves with repeated sharpening that's great. So no real surprise there...I still don't love stainless, even really good stuff.

Currently I am not settled on whether I want to keep the edge of my BG42 Buck 110 at 30 degrees total and accept a smaller burr tendency than s30v in order to have the better initial sharpness, or add a mini bevel at 40 degrees to the edge like I did with s30v and lose the burring most of the way in exchange for slightly lower initial sharpness. The 40 degree bevel is probably the right way to go, but it's SO close to being OK at 30.