Mike demonstrated piercing bowls with an air powered high speed tool spinning 400,000 RPM at 35 PSI. Pressure must be strictly regulated to not damage the tool so a separate regulator is recommended, as well as a water separator. The brand he uses is from SCM, at about $400, but expect to invest $5-600 plus a compressor to get all set up.
As you might expect there is a significant amount of fine dust and smoke generated so a mask is needed but at that speed the grain of the wood does not really affect the cut. It’s best to make the bowl very thin for aesthetics as well as tool performance. Brushes and tiny sanding pens help clean up the rough edges.
We also had a nice collection for show & tell
