I don't know if one can get a mercury switch nowadays.
Yep, you still can.
What ever happened to Erector Sets and Chemistry sets by Gilbert and American(?) Scientific and others?
The 120 AC powered motor in my Erector set, circa 1959, had a gear-reduction transmission, worm gear drive from the motor to the trans and I think would mangle anything that got into those UN-covered gears...it was a BRUTE!
We've talked about the pre-70's lack of auto set belts, metal car dashboards and pointed dash knobs, no bike helmets, missing fenders and chain guards, playground merry-go-rounds, see-saws, teeter-totters, jungle gyms and monkey bars....but I am truly amazed (and blessed) to still have both eyes, all my fingers and toes after building all kinds of stuff with my Erector set and helping one of my neighbor friends with HIS chemistry set!