Okay, (Theo did want further info): Snapper Mowers are manufactured in McDonough, GA and the design-build contractor was a client of ours for many years. There were literally hundreds of huge presses that form mower parts from sheet metal. With each of these presses there are in-coming flat sheet metal pieces and another location for pressed parts to be placed. The pressed parts are bright sheet metal "stampings" for the most part. There is a chain overhead with hooks on the links at regular intervals and this chain being literally several miles long weaves althroughout this enormous building (about 70 acres under roof). At the front of the "line" the chain appears to not be doing much, but as you follow the chain, it is getting progressively added-to with metal stampings from althroughout this enormous factory - each stamping being attached via the hooks.
Several miles (as the chain travels) down the line there become essentially bumper-to-bumper traffic of these metal stampings dangling from the chain. Intermittantly spaced there are motors that drive this chain. All of their stamped metal parts go through solvent cleaning, drying and are dragged through a many-segmented "pool of paint". The chain has high and low spots and the pool depth is fully utilized with some parts, but the chain comes to within 4-6" for several hundred feet as the parts are dragged through this "paint bath". After the paint is applied there are another several hundred feet of areas where paint drippings fall under a continuously sloping (upward) trough that drips recovered paint back into the "paint bath" (pool).
Theo, certainly you will not need to begin on such a large scale, but a miniaturized version of this could be made where a small chain could be interspersed with wood screws - heads of the screws would prevent passage of the screws. Each wood screw could go into the bottom (to be later covered with felt, etc.) of a chess piece - which would in-turn dangle from the chain at an elevation sufficient to submerge the pieces. I doubt if your quantities would require motorized chains initially, but with this system a lot of parts could be dipped into a relatively small container and dried over a piece of cardboard, etc.
As a gift many years ago, I was given a book of "How to Make your own Chess Pieces". In it was a method for using a band saw (or scroll saw?) to cut all four sides one at a time by making a cut, flip/rotate 90*, repeat, flip, bla, bla, bla. I honestly wondered if some pieces could be made in linear segments of maybe 1-2 dozen pieces and then reserve the band sawing for just 2 cuts instead of 4. Food for thought.
I hope this helps,
OPG3 Tweak everything!