M42 HSS Inlay Knife Steel

An explanation of what M42 steel is, and a discussion of its properties. August 30, 2007

A retired friend of mine told me about a knife material he bought at one time called M42 HSS Inlay. He claims it lasts almost 6 times longer than conventional M2 HSS. Unfortunately he cannot remember where he got it. Has anyone heard of it and know where to get some?

Forum Responses
(Solid Wood Machining Forum)
From contributor T:
That material has been around for awhile and many people have never used it. It does what your friend claims and it is only slightly more expensive than M2. We [Lemmon & Snoap] sell whole bars of it or finished knife sets made to your specifications.

From contributor M:
Is M42 the same thing as stellite/tantung?

From contributor P:
Stellite and Tantung are trade names for cast nonferrous alloys. Generally they are tungsten-tantalum alloys with chromium, nickel, and cobalt. Iron is not present in large amounts as in M42.

M42 is considered a "super HSS" and is an iron, chromium, molybdenum alloy.

The Stellite/Tantungs are for applications where high heat is encountered during cutting. They will actually hold their edge as they become red hot. Not what you want for wood, although it has excellent abrasive resistance.

From contributor C:
The inlay M42 corrugated steel is a stock item for Wadkin North America. Taller sizes have a full laminate of M42. The items have a part number prefix of AMT. Wadkin also stocks the M42 as a solid non-inlay corrugated knife in a number of sizes.

From contributor C:
Here's some additional technical information concerning M42.

M42 is less prone to chipping or breakage than conventional M2 on tougher applications. Rockwell "C" scale hardness for M2 is 61 to 64; M42 is up to 68. M42 is much harder to machine than M2. M42 differs from M2 in the following general chemical analysis. Manufacturers vary these percentages within certain parameters.

M42 versus AISI.M2
Tungsten 1.5% vs. 6.76%
Molybdenum 9.5% vs. 4.83%
Colbalt 8.0% vs. 0.00%

The other chemical components are very close in percentage between the two.

Tungsten: increases hardness, edge life and heat resistance.
Molybdenum: produces toughness and neutralizes brittleness of chromium. Also helps increase edge life.

One thing to bear in mind in comparing these percentages is that Molybdenum usually has twice the value of Tungsten in the final analysis of the steel being used. Since Tungsten is very expensive, you can see why some manufacturers try to use more Moly to make up for less Tungsten.

From contributor M:
I just wanted to add a note about tool steel. Titanium blades? What BS! Maybe Tin coated tool steel, but not Titanium for a cutting edge. I just want to point and laugh at the razor companies that make such stupid marketing clams. Anyone introducing ceramic tooling... cerametal? Or is it too brittle for woodworking applications still?

From contributor T:
Ceramet is being tested and used by some people in saw blades. The life is great but the brittleness makes them both hard to make and expensive to use. If you are interested in information on ceramic saws, contact Northwest Research Institute Incorporated. The last time I looked into Ceramet saws, they were the only ones who were actually making them.

From contributor I:
I have used both M2 and M42 on hardwood (red oak, hard maple, etc.). I didn't pay much attention to the difference at the time, but after the fact I could almost swear that the M2 stood up better in the hardwoods that I run.