On Monday, August 17, 2015 at 9:00:16 AM UTC-4, Joe Gwinn wrote:

Make sure that no spark energy goes through the ball bearings.
Insulate the tool from the drill press, and put a short circuit between
DP chuck and DP frame.

Joe Gwinn

I should have mentioned that. We used a wood dowel in the drill press chuck and whatever shaped tool attached to the other end of the dowel.

To be safe we should have had some sort of guard around the tool to keep anyone from touching the tool.

Dan