Question
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.
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.
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.
