On Thu, 12 Mar 2015, gareth wrote:

3D printer now commissioned ...

https://reprappro.com/documentation/ormerod-2/

... gears for tuning dial for retro "vapourware" RX here I come, (but
only after getting to grips with Freecad ...

http://www.freecadweb.org/

Make sure to properly file the details of the gears.

3D printing can be useful for "keeping parts in stock", but if you lose
the information about what you did the first time, it won't be so easy
to resurrect it down the road.

Michael