The converse was my intent. Using a track cog on a uniglide hub to replace the rare threaded Uniglide cog. Although if one already had the uniglide threaded cog, it would follow that one could also fixie via Uniglide cog. The splined cogs are less of an issue as one merely needs grind down the large spline of Hyperglide cog to fit it onto a Uniglide hub.