After a couple more tips from the guys at Wheat Ridge Cyclery and a few spent cut-off discs on my little die grinder, I finally have individual sprockets! I wasn't able to remove the smallest two sprockets from the freewheel, but I don't think that will be a problem. I don't need to use the smallest one anyway, so it can just tag along with the other. The sizes (in number of teeth) are 16, 20, 24, 28, and 32 (and a 14 I don't need). Various pairs will be used in the gear tooth cutter in order to make all the different gears for the clock. The sprockets will allow the gear blank to move in just the right way to allow successive passes of the cutting blade to trace an involute tooth profile.