Some stainless knives are hard to sharpen well

See if a file cuts the steel, at the duller part by the handle.

On Sep 22, 2019, Ignoramus9254 wrote (in article snipped-for-privacy@giganews.com):

Bench grinder? That´s a problem right from the start. Far too crude and powerful for the purpose, and almost certain to burn the steel right at the former cutting edge. The grayer steel is probably also magnetic - as others have implied, this is most likely the good knife steel.

The brighter steel is suitable for butter knives.

Some photos would help.

There is a large literature on knife sharpening, but for cooking knives an india (red) stone used with water works well.

Joe Gwinn

Hi Iggy! I don't have time to get much into this, but as Joe said, sharpening good knives on a bench grinder is a good way to wreck them. (Joe -- real India stones (a Norton trademark for aluminum oxide) are yellow-brown, not red, unless Norton has licensed out the trademark to someone who makes them red)

All stainless can be "bright," but it's the austenitic, 18-8 types (302, more or less) that won't hold an edge. However, if you sharpen them aggressively -- like with a bench grinder -- they will *take* an edge, and a bench grinder typically leaves a microscopic serration that gives the illusion of making the knife cut well. In vegetables, it really *does* cut well, for a while. And it's good for meat, too. In fact, that microscopic serration actually improves performance for most *slicing* operations, but not for *chiseling* operations, where you push the edge into whatever you're cutting. For that, you want ultrafine edges, and very sharp ones.

Good kitchen cutlery and quality pocket knives today are made from 400 Series (410, 440, 441) stainless. It is heat-treated and MUCH harder, and much harder to sharpen. (410 doesn't have much carbon, but it has enough manganese and chromium to multiply the effect of the carbon in conversion to martensite upon heat treatment). But it holds a good edge. It is rough on aluminum oxide stones -- I only use them for finishing. For hard stainless, a silicon carbide stone, which typically is blue-gray, is much better.

Hard wheels are the worst for heat build up and wrecking a good knife or other cutting edge. Soft ones, often white, are used commercially, and VERY carefully to avoid drawing out the temper.

If you have a microscope, you can learn a lot by examining the edges after you sharpen them. You'll see that some stones will not produce a really fine edge on hard stainless. The edge chips if you use too much pressure, and it doesn't do much at all if you use too little.

I learned a lot of this from Norton folks when I was writing about it, and from 60 years of screwing up good edges. d8-)

Whoops, I said "blue-gray" for SiC. Good ones often are green.

Hi Iggy! I don't have time to get much into this, but as Joe said, sharpening good knives on a bench grinder is a good way to wreck them. (Joe -- real India stones (a Norton trademark for aluminum oxide) are yellow-brown, not red, unless Norton has licensed out the trademark to someone who makes them red) ...

Well, Norton has made "India" stones for a very long time. One of my India bench stones dates to the late '40s. Another, early '50s. And I have several small stones, plus about a half-dozen India slips. They're all the same color, but they may have changed it since then.

Yes they are but so are the others

Well, Norton has made "India" stones for a very long time. One of my India bench stones dates to the late '40s. Another, early '50s. And I have several small stones, plus about a half-dozen India slips. They're all the same color, but they may have changed it since then.