Hi folks, forgive me if this issue has been discussed somewhere, but if it was I couldn't find it. I also searched Sheldon.

My question is, to what degree are Shimano Uniglide cassette cogs interchangeable? Note: I'm referring to freehub cassette cogs, not freewheels.

I have a six speed Uniglide cog set taken off an old mountain bike of mine that has since been stolen and I'm considering repurposing it on another build.

- My understanding is that the difference between 6 and 7 speed Uniglide cassettes is simply in the spacer thickness and that the cogs themselves are the same. The exception being the smallest cogs which are different thicknesses because they are threaded with a built in spacer. Is that true? What about 8 speed cogs? Could I swap my 6 speed cogs into a 7 speed cassette if I used the 7 speed spacers?

- I understand that Dura Ace small cogs are different from other Uniglide small cogs because the Dura Ace free hub has a slightly narrower diameter at the threaded end so as to allow for 11 tooth small cogs. What about the rest of the cassette? Can you use any Uniglide cog, except the small threaded cog, on a Dura Ace Uniglide freehub or do you have to use Dura Ace cogs? Are Dura Ace cogs and spacers the same thickness as the same speed other Shimano uniglide cogs and spacers?

Thanks gurus!