Need help getting the right derailleurs for a vintage 12 speed double What derailleurs do I need?


2x6 speed
52 and 42 tooth up front.
Crank set is Shimano 600


I believe the bike is a Raleigh Road Ace. I came here a month ago asking to identify the bike and now I'm aiming to restore it. I know nothing about road bikes so I don't know if all 6 speed derailleurs fit all 6 speed cassettes. Please explain as if I'm five years old haha.

Thanks.

These images will explain more than my words can.
https://imgur.com/gallery/LDbbS
There's no such thing as a 6-speed cassette. Back in the day, we used freewheels.
Indexed shifting was a new thing when this bike came out, and from the looks of it, this bike didn't have it. It has what I'm guessing are Campagnolo Triomphe or Veloce shift levers, which were not indexed.


Because shifter/derailleur/gear compatibility is necessitated only by indexed shifting, and you currently don't have that, you could throw any short-cage derailleur on this and it would work (or long cage, whatever).

If you want to get indexed shifting, then we're talking about something much more complicated. 

For starters, your rear triangle is almost certainly spaced 126 mm, but you'll have a hard time finding a hub for an indexed-shifting system that will fit that--they did exist, but the bike industry moved up to 130-mm spacing pretty quickly (indexed shifting came out around 84-85, and 130-mm hubs a few years later), so either you'll need to get lucky hunting old parts or you'll need to have the rear triangle cold-set to 130 mm (you could maybe jam a 130-mm hub in a 126-mm triangle--different people report different results). Once you've done that, you'll need to buy a new rear hub, new cassette, new derailleurs, new chain, and new shifters. And some 11-speed drivetrains will require that you get a new crank to work well, if you go that route.