Best methods for reshaping existing blades?

[shingaling]

I am new to this site. I have some (iron) foundry experience, but little metal working experience. I've always enjoyed working with knives, but I'm not exceptionally knowledgeable about knife terms, types of steel, etc.

Here is my situation: I am now working in a very large thrift store. Every week, dozens, if not hundreds of knives are donated. Most are kitchen knives, though a few folders, sheath and fishing knives show up also. Only new knives and complete block sets are put out for sale, while the rest are 'recycled' to the Third World by the charity, along with other house wares, clothes, etc. I pick through the piles of unwanted knives, and I can ask to have them priced and put out for sale if I'm interested. (Cheap!)

I am interested in buying used knives and attempting to reshape the blades for various end uses. Primarily I'd like to make general camp/outdoor utility knives, with the usage mainly being determined by the thickness and shape of the existing piece. Here are my questions:

Most of the kitchen knives found are stainless. Does the steel used in common kitchen knives differ greatly to that used in outdoor knives? Even if it does, I don't envision myself doing anything with these knives where I would notice any difference in the usability. I'm doing this for the tinkering experience, not necessarily for the outcome.

Are there any suggestions for 'high end' kitchen brands to look for? I'm obviously steering away from serrated miracle knives from Taiwan, but there's no limit to the brands, shapes and sizes that come in. I just don't know any, other than the J.A Henckel 'Twins' that my wife always buys. The only one I've bought so far is a high-carbon steel Boker (that is to say, not a stainless steel) - a standard chopper, with a 9 inch blade. Other than a brand name, aren't there usually markings on the blade indicating the type of steel used? (...and what are the better types to look for?)

What are the best methods of cutting down/reshaping blades without risking alteration of the steel properties due to heat? Surely standard bench grinders will generate too much heat. Band saw with a metal blade? Angle grinder with a metal cut off blade?

Any replies, or links to sites or threads that instruct how to reshape blades would be greatly appreciated. Thanks!

 

[Roger999]

You'd have better luck just using a blank annealed piece of steel, cutting and grinding hardened steel is a real big PITA and you're going to go through lots of grinding belts. If you insist on doing it, then you can use a band saw or a angle grinder to cut it to shape but dip it in water every 1-3secs of cutting, for grinding it I would suggest 40grit belts to grind it to shape but dip every 1-3secs of grinding and keep moving the blade, do not allow the steel to change colour, once that part turns dark blue, you've pretty much ruined the ht in that area, a light straw colour means you've ruined the ht at the surface of the steel.

 

[shingaling]

Good guidelines - thanks for the information.