"Smart Money," James Cagney, Edward G. Robinson, 1931.
James Cagney plays "Nick the barber" Lots of good views of a 1930's barber shop, and even a short scene of a guy shaving against the grain under his neck. He is doing it real fast, kind of flipping the razor, so it looks fake, but I tried it that way (only slower) and it actually works!
I also like the cupboard with a cubbyholes for each customer's shaving mug.
Fun if you like old-time barbershop stuff.