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Subject:
Re: I agree with Bill,
Response To:
Re: I agree with Bill, ()

Keith Newton
Well, besides the recommendation of no more than 1 tpi, if you choose a carbide, just note the gullet depth. Most of the carbide blades you will find on the market are for cutting steel, and just don't have enough gullet to carry all the chip material out when resawing wide boards. If the gullet gets full half way down the depth of the cut, then that wad of material is keeping the blade from advancing, as well as generating a lot of heat. As I'm sure you know this heat isn't good for the health of your expensive blade. I don't think that it's actually the heat that does the harm, but the chemicals in the wood turning to steam erodes the binder within the carbide. At least I think that is what I read many years ago. Maybe some of the chemist on this site can study up and get to the bottom of it. I recall having a discussion with a machinist friend that said to me that heat wasn't an issue for carbide, that it was just as hard when red hot as when cool. He said that it actually could benefit like a hot knife through butter. I told him I'm pretty sure that isn't how it works in wood.

Looking at the blade cleaning discussion running right now, the warnings against leaving in the bath too long probably isn't any different than acids in the wood turning to steam when there is too much heat in the cut.

Also, since you are dedicating this for resaw, you really want a positive hook angle to chisel through this dead against the grain attack. If you choose a metal type, it most likely will have 0ยบ which is a scrape cut, that will waste more power and generate more heat.

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