Several times, I felt some tingling when using my 30 year old grounded sawzall. Brand is Milwaukee. I thought that was odd since it has a grounded cord, plus I was wearing hiking shoes with thick rubber soles.
I investigated the non-gfci outlet (in the garage) with a multimeter. I was able to get ~110 volts across the two blade ports, but unable to get any voltage across either blade port and the roundish ground port. I tried the same thing on a kitchen GFCI outlet and was able to get a voltage across one of the blade ports (the small one if I recall correctly) and the roundish ground port.
I found a nearby outlet in the house with a good ground, and used it to finish the 5 minute sawzall project, but still stuck to gripping the sawall only by the red plastic handle the black rubber boot.
I haven't determined which circuit breaker controls the receptacle, or if other recptacles on the circuit have functioning grounds.
I think the multimeter results mean the ground is not working on garage receptacle. Is that right? how do I track down the problem? Does the tingling also mean I have an electrical problem within the sawzall?