I know someone who trusts to switches for assuring a tool is in "safe" mode. I won't mention any names but, I unplug. The only exception for me seems to be the drill press when changing bits. I don't know why that one is excused but, I use a keyless chuck . . . maybe that makes me think its "safe"(?). On most machines, if I am doing anything with them besides using them as designed, they're unplugged. The best security for your computer and your tool is an "air gap". A proper lockout or disconnect device as opposed to a "switch" achieves the same result; a gap adequate to assure no circuit even under adverse or emergent situations. I don't want to lose a digit (or even have to change my pants) due to that one in a million chance when it is so easy to avoid.
Last edited by glenn bradley; 04-15-2012 at 04:24 PM.
Any sufficiently advanced technology is indistinguishable from magic.
- Arthur C. Clarke