Turning Archive

Subject:
Another question on sharpening angles

john lucas
When you measure a scraper angle and say it's has a 70 degree relief. As measured from the top do you call it 70 degrees or 20 degrees. My machinist friend says he always measured from vertical so the question above for him would 20 degrees but then I said is that a negative relief or positive. He didn't have a good answer for that.

If you have a negative rake scraper and your measuring the top angle again measured from the top and it's 10 degrees would you say 10 or some other angle. Again just trying to get the language correct.

when I measure the angle on a bowl gouge I put one arm in the flute and then measure the angle down. In my case my bowl gouge is 55 degrees. It would be 35 measured from vertical, 125 if measured from the bottom. To me the included angle is more important on a cutting tool which is why I measure from the top. 55 degrees is the cutting angle of the sharp edge of the tool.

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