Choice material suggestion for pivoting arm board

I'm taking on a project this winter which I think will be a whole lot of fun and could very well turn out to be a nice surprise.

Specifically what I'm looking for are suggestions of material for custom pivoting arm boards for a Graham MKI Phantom arm including the beautiful Technics EPA-100.

Be it bronze, high grade steel or a combination of sorts machine shop services are available.

This project will revolve around a Technics SP10 MKII in a custom two arm plinth.