If the existing cups are still usable, all you need is a spindle of the appropriate length for your crank.

If they're not usable, then you'll need to consider a cartridge of some sort. As noted, Velo-Orange offers a threadless cartridge, but recently they added a French thread version of the same thing:

https://store.velo-orange.com/index....y-cups-26.html

And Phil still offers French thread mounting rings for their bottom brackets.