Have you considered using Carbon Fibre, as a modern material ?

MichaelG.

Black Delrin is another alternative.

Emgee

Are the black pieces also to be made from brass?

Never used the Carr products, but it appears to be a chemical conversion treatment. The one for steel is most likely regular selenium-based cold blue which work OK but won't be nearly as wear resistant or decorative as a caustic black treatment.
A proper caustic black bath can be made from 3 parts sodium hydroxide and 1 part potassium or sodium nitrate. There should be a thread or two on this somewhere on this forum.

There are several formulations that will produce a brown to black patina on copper alloys, here are a few:

https://davidmbowman.com/patinas/formulas.htm
https://www.sciencecompany.com/Patina-Formulas-for-Brass-Bronze-and-Copper.aspx

Aluminum can be anodized and dyed into almost any color.

I've used both the Carrs and Birchwood Casey brass blacking solutions and despite every care and degreasing in a variety of ways have only ever got a dissapointing deep brown, ok from a distance but wouldn't call it a proper black. The Birchwood Casey gun blacking (or blueing I think they call it) does work very well as does a steel blacking kit I bought from Frosts, careful degreasing seems to be the key to a lasting finish. I heated and oil blacked parts of my Simplex and they are still ok 40 years on, again to get an even finish careful degreasing is key.

why not consider stainless steel as white and brass as black – this will give the pieces some weight (corian would also be heavy but light plastic pieces always feel wrong) – the board could use brass + stainless steel foil glued on a wooden base

Hammerite Kurust Rust Converter or it's equivalent. This is a surface treatments for steel based on Tannic acid, so leaves the base metal a deep navy blue.

Other maker's equivalent preparations give much the same results. Jenolite make one, also Vactan, and Aquasteel.

Loctite also make one but it's expensive though a little goes a long way. I've recently used one called Neutrarust 661 which seems to work. I thought the resulting colour was more dark brown than blue or blue-black, but the part (a wheel rim) was pretty rusty!

Getting an even coating is going to be about cleanliness – try caustic soda rinse first. Maybe an uneven coating can add to the character of the piece.

Do do a show and tell afterwards, please!

Black paint ?

Just asking !

Make them from steel and then apply Abbey Blue Gel as used for gun barrels. A couple of applications should give a nice dark blue colour. Fix the colour by wiping with oil or waxing.

Russell

you can get a patina solution from jewelry suplies sales.

Patina Oxidising Solution 250ml UN2922

this will give a dark finnish to silver, copper and bronze.not expensive but needs handling with care.

David

Anthony, your fastenings chess set is utterly charming

Rod

I love it