A couple years ago, I bought a handful of folding belt knives. Chinese made, $3.00 each, stainless steel. It's hard to go wrong on a $3.00 knife as long as you don't expect any more than $3.00 worth. One of those knives hangs on the corner of my garden shed. Its purpose is simply to trim up vegetables before I bring them to the house. (A very good application for a $3.00 knife.)

It's probably been used about three years now. It was getting dull. Usually I just rub it on a rock (which are plentiful in my garden) but this time I thought it needed a little more. On close inspection, I noticed a little chip out of the tip. No big deal, I'd just polish it out on a whetstone.

That's when I made a very unusual observation. As I worked on a coarse stone, trying to reshape the blade, the fine edge just kept breaking off. When I worked the edge down so thin, it just broke away! Finally I took it to the wheel sharpener. In essence I had to grind away all of the original bevel and edge until I got to the place where I could again sharpen the edge.

I wonder what went on. My guess is that they tempered the blade after they put the sharp edge on it, and that made the thin leading edge of the bevel brittle.

Anybody else got any ideas?

Hal

I think your right..I have some pocket knives here the same thing happened to. I bought 2 cases of them for .50 cent each at a liquidator that was going out of business.I handed them out for years to my friends

Pretty hard to figure Heat treatment into a knife that costs $3, even in China.I would assume those blades are whatever hardness the blanks come in as. A sheet of "stainless" work hardened by rolling is going to be somewhere about 20 on the Rockwell C scale. "Stainless" at that hardness would exhibit the edge holding properties you describe, IE pitiful

But, once I ground away that brittle edge, I was again able to sharpen the knife.

Hal

This is only a guess as I have no idea how to make a $3 knife.

Possibly, as the factory edge was ground the blade edge was heated up enough to temper it. That steel was probably as hard as it could get.. and brittle. Once you ground back from the tempered edge you got into metal that was less affected by the grinding heat and could maintain a garden edge.

To clarify a bit...

A blade too soft will be weak, the edge will roll over

A blade too hard will be brittle, the edge will chip/break

Temper is underlined above for a reason. Tempering the blade is only one part of the heat treatment process.Simply put,when a blade is tempered it is usually in a state unfit for use. It must then be annealed (made softer)to a point that suits the steel and the blades intended purpose.

Surprisingly, I do understand that, and it makes sense. -- Hal

Having inferior raw materials, no environmental concerns and partaking in extreme exploitation of the workers involved might help you understand.

Sounds like some High Quality $3.00 Chinese Stainless Steel!

Give me the choice between a $3 knife and a rock for a garden tool.I'll choose the knife every time. Those knives are perfectly suited for Hal's intended use.

No need to have a $200 knife to cut the stem off a squash