On Fri, Jun 10, 2011 at 4:52 PM, YES NOPE9 wrote: > Yes I would like to make this into a FLOSS product. > Yes , I think magnets are the way to go for holding force. > Yes, I expect users to unplug the tool while under power =A0( I can't con= trol what users do ) > > It would be great if the extension cord is "sucked" onto the tool connect= or and held with great force. > It would be great if this force could be =A0"turned off" easily to allow = disconnection. Rare earth magnets will definitely give you the force you are looking for. Turning off that force is difficult, but you could use a lever/wedge to separate the magnets. If you wanted to avoid arcing when the device is disconnected under load, a combination of spring-loaded pins, a sensor to detect the start of physical disconnection, and an electronic cut-off could be used. Such a system is eminently do-able, and the designer in me would love to work on such a project. The practical side says to just use twist-lock connectors or (as someone else mentioned) air tools. -p. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .