Hi Fireguy, I have to add my voice - while I see other clockmakers run their watchmaker's lathes with just a motor and a drive belt, I think that it's important to use a countershaft (also called a jackshaft and a couple of other things) in your setup. The reason it's important is because it not only slows down your lathe but it also increases torque. Most watchmaker's lathe motors run several thousand RPM's, and the most effective work on your lathe happens when your spindle speed is somewhere between 500 RPM and 800 RPM, especially for hand turning with a graver. There are times that higher speed is required, like when cutting steel with a carbide graver.
On my countershaft, the motor drives a larger pulley. Next to the large pulley is another stepped pulley hand-turned to match my lathe's headstock pulley, but mounted in reversed direction. The two pulleys being the same diameters but reversed allows me to shift the drive belt from the left position, middle position and right position to give me 3:2, 1:1 & 2:3 ratios. Of course, there's always the three-step pulley on my motor shaft, as well as a small pulley adjacent to my large pulley on the countershaft - so there's plenty of choices. I have to say I'm very happy with my setup as I have it now.
As a final touch, it's not a good idea to leave tension on the headstock overnight, so I made the drivebelt on the headstock with plenty of slack. When I'm ready to run, I spin the headstock a few turns by hand to distribute residual spindle oil, and then use a magnetic-base-mounted idler pulley to take up the slack. I usually add two drops of spindle oil to each oil cup every other day.