Using bench power supply to drive ex-cordless driller
Don't know what the guy at the local electronics shop was smoking, but it's very common to drive dc motors with a switch-mode power supply. That's effectively what the variable speed trigger in the drill itself is doing already and it's what millions of radio-controlled modelers do with their motors every day. But even so, the output from you bench supply will be reasonably well filtered and smoothed, so its much the same DC as what you would get from the battery originally fitted to the drills. So by all means crank up you bench supply to 18v, set the current limit up to something sensible and go for it!