On 13 Oct, 13:26, Jules
wrote:

How come vertical axis is more expensive? Purely because horizontal is
more common?

Partly, although that's changing.

AIUI, there are two sorts of vertical axis machine: those that put
one hell of an oscillating load on their (thus expensive) supports as
they rotate, and those with complicated twisted blade designs that are
easier to support, but need more costly ways to make the blades.

Mind you, if you want to see the horribly inflated cost of machining
anything these days if the volume's small, take a look at the GWR
Railmotor reconstruction period and the prices their connecting and
motion rods were costing.