When converting a 1/2" fw to inch-pitch, it is highly recommended to start with a unit with an even number of teeth. :-) harvey sachs mcLean va
I've never seen a "store boughten" one, but I have seen 1/2" freewheels modified by grinding off every other tooth. Doesn't look too difficult, but I've never done it. Another job for one of my favorite tools, the bench grinder. Make sure not to overheat the sprocket.
Sheldon "Sparks" Brown