Composition/Properties of Kromedge Steel

[Doug Hepler]

Hi, Metalurgists

Does anybody have a reference on Kromedge steel? Is it similar to high carbon steel or more like HSS? I know that it is (was) a proprietary Sears alloy and that they used the name a lot as a selling point for tools over the years.

I inherited a set of Kromedge turning chisels, probably from the 1930's-40's. I use them regularly, especially the gouges, along with newer HSS chisels. I sharpen on a white HS wheel and I usually manage to keep the edges from overheating. But I often wonder what kind of steel I am working with.

Doug

[Jamie Buxton]

Chrome is one of the common elements used to alloy iron to make HSS. I'd guess that Kromedge is an HSS.

[Jason Edwards]

Look up spark tests for steel alloys and have a look at the pictures. High carbon steel, like a file, will have light yellow sparks and lots of "sparklers" - you'll get what I mean you see the pictures. High speed will have more of a reddish spark without as many sparklers. It's not exact, but you can readily tell the difference between high carbon and high speed.

[Lisa Starr]

It is some type of Chrome-Nickel-Molybdenum alloy, probably akin to A4340 Alloy Steel.

[Peter Christensen]

Sears advertised that Kromedge was a Chrome, Nickel, and Molybdenum steel for their saw blades . That doesn't mean it was a HHS or Stainless steel. They could be in the same category as 4340 which has lower amounts of the alloys or something in between. Since some knife makers use saw blades to forge knives from I doubt it was a HSS or SS material since they don't hand forge well. I will sit corrected if wrong.

While HSS can be sharpened and blueing won't affect the edge you can't do it with a carbon steel as it will soften. I wouldn't overheat your chisels as I believe they are a carbon steel. HSS didn't become widespread in woodturning tools until the late 70's or early 80's and Craftsman wouldn't have been at the forefront of developing them.

Lisa beat me to it. I type slow.

[Doug Hepler]

Thanks to all. I will play with sparks.

Doug