I have just tried out Gary Millard's DXFNipkow program to create a 20" Baird 30 line 7:3 disc. The preview looks as it should.
Now, my question is - the dxf file created - can this just be fed into a CNC machine or laser cutter?
I am curious about this because the aluminium supplier where I got my original discs from is CNC and CAD equipped. If it is that simple, then it would appear possible to replicate Baird's Plessey televisor disc in quantity.