Basically the wheels are well on the way, I need to add further details to the front and larger middle set then I'll have to sort the thorny problem of how I seat the 2 Dwarfs and where I add the spikey parts. :-)
So far I have used cereal card, card packaging, a box of stuff from Ebay and some dowel I bought ages ago (it was in a sale 60p) to make pillars with and will probably never all get used. And of course and bit of hardboard for the base.
As I was in the garage I cut wheel parts and base sections for 2 complete machines, but Ican almost feel the third on calling to me as I speak.
It does occur to me that these wheels look something like the cogs and gears that appear in the titles of Game of Thrones. They might also make interesting terrain as well.