Military Question?

R

RickJ

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Mar 2, 2003
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In the past few months I have purchased both the BG-42 CF and the New CPM D2 Millies! I want to know the Hardness of these blades and a comparison of the two steels, benifits of either.

Both were razor sharp out of the box but the D2 was the sharpest out of the Box, could have been a better worker doing the D2 blade, both are super sharp! any info would be good.

Thanks
RickJ
 
I'm sure Sal does, so when he gets back in the country and catches up on all the other projects he has going, he'll likely answer you.

It might be faster to have yours Rockwell tested, though. That way you would be certain exactly what yours are, instead of settling for the heat treat hardness range goal that Sal will give you.
 
BTW, I apologize if my previous answer offended you, rereading it, it came out sounding snottier than intended:o

I really don't know all that much about various steels, other than what works for me in my use, but here is what I do know about these steels from my admittedly limited experience.

BG-42 is an old ball bearing steel that was formulated to withstand very high load pressures and withstand shock loading. It takes a very fine, high polished edge and holds it very well in normal use. My BG-42 Military chipped severly when I first used it, due to an encounter with a hidden finish nail. Since I reprofiled it while repairing the damage (at a more acute angle I might add) I have had no further chipping. I suspect that it may have been fatigued steel at the edge from factory sharpening, but I haven't tried cutting any more nails to test it.

D2 is a tool steel, formulated for cutting steel. It has a high wear resistence, good toughness, and pretty good corrosion resistence, but it is not classified as a stainless steel. Your Military's blade is made from an experimental batch of steel that Crucible (CPM) made, essentially to see what their particulate technology would do to it. I heard a rumor that it is probably going to be the only batch they ever make, since the gains were too small to make the cost worthwhile. If it performs as well or better than my other D2 blades, it should be great for hard use, but I haven't had mine long enough to really wring it out.

Right now, I am running a daily use steel comparison (actually I have been doing it for years with various knives) featuring a Military trifecta: BG-42, D2, and 440V. I'll let you know if I find out anything interesting.
 
Could you elaborate some on the chipping experience you had? I have a 440V version myself and recently got the blade hung up on a thick metal rod when breaking down a box that I didn't know had steel reinforcement. I thought it was glue or something so I actually put more pressure on the knife and really layed into it, then saw what it was and checked my edge to find a good bit of damage. Mine is reprofiled at a more acute angle than factory but it didn't chip, it just rolled a lot and flattened in some spots. Most of it cleaned up with a minute or two on a diamond hone and a steeling. The rest will come out over sharpenings. I plan to get a D2 version whenever funds permit.
 
I was working overhead, reinstalling a bathroom vent fan, which was a little large for the opening it came out of. Yeah, I know, it came out of there, it should go back in, but it didn't want to. I figured it would be easier to make the hole a little bigger than to make the fan housing smaller, so I pulled out the Mili to shave down the side of the rafter on one side of the hole. First couple of passes, it sailed right through. Third pass felt like I had hit a pine knot, just a bump. Forth pass the blade stopped on the same spot where I had felt the bump, so I used a bit moe pressure to try to sheer through what I thought was a small knot, but no go. Then I tried it from the other direction, still no go :o

When I checked the edge, it was chipped in three places. Not rolled or flattened, pieces were broken out. The worst was about 3/16 of an inch wide and half the depth of the edge bevel. It took about half an hour on my DMT coarse diamond bench hone to remove the chips and even out the bevels (the grinds were uneven from the factory).

From what I have read about BG-42 since, I have come to think this was abnormal performance, and to suspect either metal fatigue or overheating of the edge during factory sharpening. I put the Mili back in the work rotation a couple of months later, and it has performed admirably since the reprofile.
 
Since Mr. Glesser seems to be back and throwing out a post or two, I thought I would kick this back to the top where he might see it. Maybe we can get you a better answer, Rick.
 
RickJ said:
In the past few months I have purchased both the BG-42 CF and the New CPM D2 Millies! I want to know the Hardness of these blades and a comparison of the two steels, benifits of either.

Both were razor sharp out of the box but the D2 was the sharpest out of the Box, could have been a better worker doing the D2 blade, both are super sharp! any info would be good.

Thanks
RickJ
Click to expand...

According to Sal (the answer to my question) Military's BG-42 is hardened to Rc 61.

Perhaps, Sal could give a number for CPM D2, too.

Franco
 
Thanks! Yab for kicking it back on top, I would like to know the Hardness of these two steels.

RickJ
 
:foot: After I reread my first post, I figured you had me on ignore :o Man, did that one ever come out wrong.

If gunmike1 should happen by, he might know. He had one of the test pieces for a while.
 
Was not offended at all by your first post! I was just looking for the steel hardness and still hope to get it if the Big Guy will chime in.

RickJ
 
I don't know the hardness of the CPM D2 Military I tested. After all of the testers are done with it we will get it Rockwell tested. I haven't used the BG 42 version, though I do recall hearing 61 RC as the hardness on it.

Mike

Edit to add: I highly recommend getting your blades Rockwell tested if for no other reason than to satisfy your curiousity and see how well your impressions of the blades performance match up with the actual hardness. I had about 10 of mine tested and had a couple small surprises. E mail me if you want to know who I had test mine, and you can give him a call.
 
Well, I guess I liked the CPM D2 Military that I tested enough to buy one. I called New Graham today, had them make sure the lock up was solid on the one they picked out for me, and I should have it by Wednesday. I plan on testing it against some of my other Spyderco Flat grinds in some rope and cardboard cutting (S30V, VG-10, and ZDP-189) to see how it stacks up against those steels. I will also get it Rockwell tested, and I can see how it does compared to the testor I used. This is the first liner lock that I've bought in a while, but the overall design of this knife was very impressive to me.

Mike
 
Looking forward to your test results, My D2 Millie was scary sharp out of the Box, I read on another post that Crucible will stop making CPM D2? because it is hard to produce, does anyone know anything about that?
 
Usually I freehand sharpen my Millies but I got one of those pre angled rod deals that come in a little wood box, I think the angles are 25 degrees and 17 degrees, which shoukd I use for the Millie?

RickJ
 
Is that 25 and 17 per side or inclusive? if it is per side, I'd say the 17 should work okay.
 
I reprofiled the testor to 10 per side with a 15 per side microbevel with no microchipping. The 17 setting should work fine. On my knife I will take it to 10 per side and leave it there, then find out how obtuse I need to go to avoid microchipping with my microbevel. The 10/15 profile seemed pretty good for medium/hard use, as long as you aren't tryong to cut metals.

Mike
 
FWIW, I tested my D2 Military/SE Sal gave to me as a present:cool::thumbup: on the materials below.

I didn't put another edge on it or something. Just used the factory edge.

After the cutting the blade still shaved, but missed a small micro chip out of one scallop which was easily sharpened away.

Didn't do any further cutting with it though:o

D2Milicutting.jpg
 
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