[rotorwrench]

A lot if it's rusty. The metal has to be polished out. If it's pitted, it has to be copper plated as much as it takes to be able to polish the pits back out. The nickle can be plated on after all the copper work is done. The time involved is all the polishing that's required.

Here in the US, plating shops have to meet stringent regulations about containment of heavy metal solutions for plating and the solutions are expensive to maintain. This plus the time involved in the polishing work adds up pretty quick. If you can find a plater that will let you do the polish work then you can save some money but not all of them will do that.

A lot of this stuff is done in countries that have few regulations but it's usually for new reproduction parts. Some have good plating jobs and some don't but the thing has to fit like original as well.