Algodoo

This is a working gear clock with a sweep movement. It is 100% accurate. It is driven by a motor. You can see the gears inside.

To set the time: Left or right arrow key to move the hands to where you want. Setting the time takes up to 15 seconds.
Then, drag the blue minute hand onto the exact spot where you want.

I don't recommend using just the drag tool to set the time entirely, otherwise the gears may skip the teeth they mesh in.