odie
TOTW Team
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- Dec 22, 2006
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I still see those "spiraling" cuts occasionally, but I know what's happening by the feel of the tool......and, know what the cure is. These days, it's not much of a problem, because, as with most of us that have been turning for some time, the cure is an automatic response......That's because we've been down this road so often before.........
To someone who hasn't been turning for very long, the spirals can be intimidating, because there isn't yet an established "cure" in his (her) personal "bag of tricks"........This is a major frustration!
THE CAUSE........What's physically happening between wood and cutting edge of the tool requires a little speculation on my part......but, the cure is always the same, so it really doesn't matter if I'm right.....or wrong in the theoretical origins of the spiraling cut, because the preventive measure is always the same. First, understand that the grain of wood is made up of annular rings. If you sandblast the wood, it's obvious that the grain is softer between the rings, and the ring itself is harder. If conditions are just right, the cutting edge of your lathe tool will tend to rise where the grain is harder, and not rise where the grain is softer. My best guess is: This is the point where the spiraling cut first initiates. After the spiraling cut is established, it's no longer the annular rings that are effecting the continuation of the spiraling cut......but, it is then continued by the ridges that preceded it......the more the cut is persisted, the worse it will get. For the newer turner, there are three things that will contribute to the spiraling cut.......sharpness of the cutting edge, feed rate, and presentation. The more experienced turners will know what the proper presentation is, so for them......there are only two things that are critical.
THE CURE........First, stop what you are doing. Go back to where the spiraling cut first started, and re-initiate the cut at that point. You HAVE to go back to the beginning of the spiraling cut, or you'll NEVER be able to eliminate it. If reducing the feed rate, or adjusting presentation doesn't solve the problem...... re-sharpening is necessary. The problem could be a combination of any, or all of these three things, but feed rate, sharpness of cutting edge, and proper presentation are the cure, and the reasons why it's not working for you. Looking back 20+ years ago, I'd have to say that learning how best to get an extra sharp cutting edge on my tools has resulted in the most problem free cutting action on difficult wood.......this is not to downplay the importance of feed rate and presentation, however.
ooc
To someone who hasn't been turning for very long, the spirals can be intimidating, because there isn't yet an established "cure" in his (her) personal "bag of tricks"........This is a major frustration!
THE CAUSE........What's physically happening between wood and cutting edge of the tool requires a little speculation on my part......but, the cure is always the same, so it really doesn't matter if I'm right.....or wrong in the theoretical origins of the spiraling cut, because the preventive measure is always the same. First, understand that the grain of wood is made up of annular rings. If you sandblast the wood, it's obvious that the grain is softer between the rings, and the ring itself is harder. If conditions are just right, the cutting edge of your lathe tool will tend to rise where the grain is harder, and not rise where the grain is softer. My best guess is: This is the point where the spiraling cut first initiates. After the spiraling cut is established, it's no longer the annular rings that are effecting the continuation of the spiraling cut......but, it is then continued by the ridges that preceded it......the more the cut is persisted, the worse it will get. For the newer turner, there are three things that will contribute to the spiraling cut.......sharpness of the cutting edge, feed rate, and presentation. The more experienced turners will know what the proper presentation is, so for them......there are only two things that are critical.
THE CURE........First, stop what you are doing. Go back to where the spiraling cut first started, and re-initiate the cut at that point. You HAVE to go back to the beginning of the spiraling cut, or you'll NEVER be able to eliminate it. If reducing the feed rate, or adjusting presentation doesn't solve the problem...... re-sharpening is necessary. The problem could be a combination of any, or all of these three things, but feed rate, sharpness of cutting edge, and proper presentation are the cure, and the reasons why it's not working for you. Looking back 20+ years ago, I'd have to say that learning how best to get an extra sharp cutting edge on my tools has resulted in the most problem free cutting action on difficult wood.......this is not to downplay the importance of feed rate and presentation, however.
ooc
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