I'm making two pens with purple heart and some type of ebony. I'm using the pen mill in my drill press; been doing this for quite a while with no problems. Anyway, the wood starts smoking before I even get close to the blank being turned down to the tube. I checked the Janka scale and note that purple heart is halfway down the scale. Some type of ebony is at the bottom. With what I'm seeing, I figure ebony is about two steps above tool steel. I touched up the mill with a diamond file but that really didn't do much good. Your help is appreciated.