Originally Posted by JohnDThompson

1mm thread spec is not the same as 24tpi thread spec. A Peugeot frame with a cottered crank and 1mm thread is almost certainly "French" thread, and an English/ISO bottom bracket will not work. You can either source a French thread bottom bracket on the used market, or from Velo-Orange or Phil Wood, or use a threadless cartridge bottom bracket. Exactly what will work for you will depend on the crank you intend to use when you build the bike.