Once upon a time, long, long ago, there was a company called Maeda Industries. They made many fine bicycling-related things, called Suntour, until one day, the evil giant Shimano slew them.
I thought: the nicest freewheels known to mankind deserve another chance at life, so I converted them to serve as single-speed freewheels on retro-city cruisers. Any Winner or Winner Pro cluster bodies, with their salvaged screw-on cogs (the larger threading) will work. You can grease the bearings and pawls, as well, through a very small grease port, normally covered up by the mounting thread. Give the bigger splined cogs to the recycling man for scrap. This is the sort of stuff I do with my spare time. Sheesh. 🙂
p.s. notice the Microlite cluster body? Once upon a time, this was essential bling for one’s ‘superlight’ (sub 10 kg) race bike. The cogs were aluminium, and wore out quickly. However, you can retrofit the Winner steel cogs, because they are the same threading.