It is my best guess that the "W" or zigzag marks are hardness test marks.

The various marks have been discussed quite a few times, but I have never seen where Jerry or Dan have ever commented or confirmed the cause of the marks. So, Speculation appears to be all we have.

From what I can find, certain hardness testing equipment can apparently be programmed to test in various patterns - including "Zigzag" patterns and similar. I "assume" there are benefits in testing in a "Pattern" vs. the MUCH more common method of hardness testing with a "Single" dent.
I have found "information" and descriptions of testing equipment capabilities to support certain Hardness testing machines being capable of such patterns.

However, I have searched and I cannot find ANY other "picture" examples of zigzag hardness testing patterns on steel on the web to compare. I would love some help on finding such pictures.

Hardness can be tested via a few different methods, but generally involves indenting the steel with either a tungsten carbide ball or diamond. I think most of the knife industry and industries using similar types of steel seem to be using tungsten carbide balls. The measurement of the indentions confirms a hardness reading.

In theory, testing in a wave pattern should assure better consistancy of the testing.

Puma knives are somewhat known for their "Hardness Mark" on the ricasso or flat grind areas of many of their blades. Puma obviously only makes "ONE" single indention measurement per blades. Puma generally even puts a sticker on the blade pointing out the hardness mark.

MOST knife companies and similar makers and fabricators of steel who do hardness testing seem to test with a "single" dent method. I assume these singled dent testers are MUCH cheaper to purchase and own.

If these marks are truly hardness testing, Busse apparently tests in a zigzag / "W" pattern. - Which should be a bit of a credit for more extensive hardness testing than most of the industry.

Having stripped many Busse knives, I have seen these marks at random locations on the various parts of the knives.

I have never seen the marks on the primary grinds, so "apparently" Busse, cuts blanks (either laser or water-jet most likely), heat-treats flat bar stock, tests hardness and defects, primary grinds and then either coats the blades or flat/surface grinds the various satin/LE blades. Then handles. Sharpening is generally last for most makers.

My guess is the dimples and stretch marks are effects from heat-treatment (?????).


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