sheaffer

Hello, I am trying to make custom barrels for some Parker 21s, 51s and Sheaffer imperials, dolphins and legacys (the cartridge converter models) does anyone know what taps I will need for the barrel threading for any of these? Any help would be greatly appreciated. Thanks,

I just got these two Sheaffer fountain pens that were my grandfathers. The resin on these is in pretty good shape but the metal components on the outside of the cap are pretty corroded. I think they are piston filled but I'm not sure how to use the mechanism yet or test if they still work...