Gerber Mini Magnum - M2 Steel - Beating Me Soundly.

[J Thomas]

Hi All,

I picked up some Shapton Glass Stones (500 - 2,000 - 16,000) and an Atoma 400 at Christmas. So far, so good.

A friend asked if I could sharpen his hunting knife; it turned out to be a Gerber Mini Magnum from the 60's or 70's in M2 steel.

Now, the edge was pretty much gone so I jointed it (Harrelson Stanley method) and started to work on establishing a new relief bevel with the Atoma 400 at roughly a 15-17 degree angle, not a problem.

Now the problem, trying to establish the apex/cutting angle with the Shapton Glass Stone 500 at a 23-24 degree angle. It's not happening. I'm doing what I've done before and I can't cut paper well, can't catch my thumb nail well, nothing. Out of frustration, I dulled two kitchen knives, and re-sharpened them using the above method, no problem.

Can M2 steel work harden over the years?

_____

How I did the above sharpening:

Sharpie marker used, I'm hitting my cutting edge.

Atoma plate - used edge leading strokes

Shapton Glass Stone - used edge trailing strokes

Feel free to share your insights or wisdom - I'm lost here, first knife I can't get sharp - worse part, it's not mine.

Thank You- JT

 

[jpm2]

I'm not familiar with your stones, kitchen knives, or even the mini magnum, but am intimately familiar with hard M2 and other HSS blades.

All I can tell you is what I do.
Raise a noticeable burr with every progression.
Don't go above ~1500 ansi, I usually stop around 600-800.
Always use edge leading unless you're scrubbing, and except for very light strokes on a strop, or the very last stone.

Although I sometimes go below 25 inclusive for special purposes, more often stay in the 25-30 range for general use.

 

[Obsessed with Edges]

M2 is LOADED with a lot of hard carbides, formed by vanadium (2%), tungsten (6%), chromium (4%) and molybdenum (5%). Add all those up, you're talking about carbide formers making up about 17% of the alloy's content. All of those carbides, by themselves, are anywhere from 2X-3.5X as hard as the basic iron + carbon matrix making up the remaining 83% of the steel's content. By contrast, typical kitchen knives likely won't have enough hard carbides at all, to be significant. If present individually in the steel at the percentages listed, most of the carbides shouldn't be much of a problem in sharpening on decent man-made stones; but when they're all adding wear resistance in tandem, I'm sure it'll make for some slow grinding and/or less than clean finishing at least. I wouldn't bother using anything but a diamond hone, especially for finishing stages. Use the Atoma 400 to the finish, and see how much difference it makes in creating a crisp edge.

If the 23-24° finishing angle mentioned is 'per side', creating a 46-48° inclusive, I'd think that's not helping much in getting a clean, paper-slicing edge either. As mentioned, an inclusive angle at the cutting edge of 30° or less should work fine (or even great) for such a blade, if the hardness is decent (and if it isn't, it's a waste of such a steel).


David

 

[J Thomas]

jpm2 & Obsessed with Edges,

Thank You for the insightful and experienced advice. I will change my angle from 23-23 degree per side to that of 14-15 degrees. Also, I'll work with the Atoma 400 plate more than I have been.

Again, I appreciate the help and knowledge, all the best.
JT

 

[jpm2]

Oh man, I didn't realize you were doing 24 degrees per side.

 

[BluntCut MetalWorks]

Trivia
http://www.zknives.com/knives/steels/steelgraph.php?nm=M2,M4&ni=,5&hrn=1&gm=0
Hardened M4 carbide volume is around 13%, so M2 (with 1%C) carbide volume be around 7-7.5%.

 

[Jason B.]

The Shapton Glass stones will handle that steel just fine but you need to make the edge sharp on the 400 Atoma before the Shaptons will do anything.

Also, jointing the edge is a finishing technique done on the 16k stone. You simply flattened the edge to remove damage. Two very different techniques.

 

[arty]

I have some old Gerbers in M2 dating from a long time ago. I use the Pixie in the kitchen almost daily. Spyderco ceramic stones work, but I have never let the knife get really dull. M2 is great steel, but I would be tempted to use a diamond stone or a belt grinder for a blade that needed a new bevel.

 

[DeadboxHero]

All the old Gerber stuff is m2?

 

[Obsessed with Edges]

All the old Gerber stuff is m2?

I doubt it. I have an old '70s vintage lockback in brass w/wood inlay from Gerber (Portland, OR), and was touching up the edge on a medium Arkansas stone yesterday. Even that stone seemed to take steel off pretty easily, judging from the swarf collecting on the stone. Not sure what steel it is; I'm assuming stainless, but even that's not certain in my mind. I can't see it being as carbide-rich as M2. Maybe it came after the M2 era from Gerber, but I don't really know.


David

 

[DeadboxHero]

Here's a customers knife I haven't got to sharpening yet.
Chrome plated m2

Whoa


From some reading I guess they did make M2 Knives with chrome plating.

Wow, genius.

HRC 60-62.

Proved too difficult to sharpen for the masses.

I'll have to try it out.

It's a shame no one else has made chrome plated tool /carbon steel hunting knives.

That's the best of both worlds.

 

[DeadboxHero]

I doubt it. I have an old '70s vintage lockback in brass w/wood inlay from Gerber (Portland, OR), and was touching up the edge on a medium Arkansas stone yesterday. Even that stone seemed to take steel off pretty easily, judging from the swarf collecting on the stone. Not sure what steel it is; I'm assuming stainless, but even that's not certain in my mind. I can't see it being as carbide-rich as M2. Maybe it came after the M2 era from Gerber, but I don't really know.


David

Here another one with a wood handle.

Sharpened great on diamond

I thought it was really hard 440c

Blade was very chrome like though.

 

[kwackster]

If the knife has a sword on the handle next to the brand name & model then the blade is M2 high speed steel with a hard chrome top layer, like on this Gerber Mini Magnum:

But if the knife has a capitol "S" inside a circle on the handle next to the brand name & model then the blade is 440C stainless, like on this Gerber Pixie / Bird & Trout:

 

[jpm2]

Here's an older thread about the gerbers.

 

[BITEME]

I use the dmt extra extra coarse diamond stone(usually makes quick work of any steel,s110v included) to set most of my super steel edges,then I make my way up to a ceramic stone.I have a few of the m2 Gerbers and have used the dmt ,they take nice edges.

 

[Top Gunner]

If the knife has a sword on the handle next to the brand name & model then the blade is M2 high speed steel with a hard chrome top layer, like on this Gerber Mini Magnum:

But if the knife has a capitol "S" inside a circle on the handle next to the brand name & model then the blade is 440C stainless, like on this Gerber Pixie / Bird & Trout:

K kwackster Not sure if you’re still active on here - doing some research on a Gerber Shorty that my father gifted to me years back. On the underside of the handle it reads, “GERBER SHORTY”, no sword, no circled S, nothing besides those two words. Any idea what this means in terms of steel type and dating?

My father has a memory as bad as me, but he believes he got it around 1968. Could be that it predated Gerber’s stamping in this regard.

Open to replies from anyone who has info on these Gerber armorhide-handled knives. Thanks.

 

[FK]

Years ago I had a nice collection of the Gerber Armorhide knives, one was the Shorty.
The grey coated aluminum handles had M2 steel with a chrome plating to prevent rust. Excellent in their day however, were not popular due to difficulty in sharpening the M2 steel.
Sold them off to collectors in Japan.

I recommend diamond plates and maintaining with leather strop having diamond paste or CBN paste.
Amazon has some low cost diamond plates that will work fine but will not last as long as the higher priced DMT made in USA.

Regards,
FK

 

[EngrSorenson]

This is fascinating- I’ve sharpened M2 turning tools without much trouble on some diamond stones, but it seems these older Gerbers were pretty hard. What a far cry from the typical Gerber we see today…

 

[sickpuppy1]

K kwackster Not sure if you’re still active on here - doing some research on a Gerber Shorty that my father gifted to me years back. On the underside of the handle it reads, “GERBER SHORTY”, no sword, no circled S, nothing besides those two words. Any idea what this means in terms of steel type and dating?

My father has a memory as bad as me, but he believes he got it around 1968. Could be that it predated Gerber’s stamping in this regard.

Open to replies from anyone who has info on these Gerber armorhide-handled knives. Thanks.

I think those are made from compressed tin foil......