impsandthings: Making wheels

I've been struggling for a while with making wheels. either as part of an automata or just cutiing round shapes from wood, especially for wheels. Where possible I've used found bits of plastic, which has been fine, but as I experiment more with automata this is not always enough. When I started thinking about my latest project, a steampunk racing car, I knew I'd need to come up with a practical solution.
There are various options:
You can buy circle cutters for pillar drills which are fine for small circles and cogs. they are relatively cheap and some are adjustable.
For larger circles, such as the wheels of the car I'm making, I need something else.

Below you can see various wheels I've made today:
First some plastic bits I had lying around; either too small or just not the right look.

Secondly I tried cutting a shape from MDF, lots of careful measuring and drilling holes, but still not what I wanted. However I did realise when doing this that having the wood on an axis allows for a smoother and more accurate cut. Initially I held the wood by hand and rotated it applying pressure to the centre. Better than before but not perfect. My next job is to rig some kind of clamp to my saw that allows me to do this. I figure if I have a dowl spindle in the centre of the circle I'm cutting and attach this to a clamped arm I will have a reusable tool for cutting circles.(we shall see)

The final wheel was again hand cut but with brass spokes added. Again careful measuring was needed to mark the spoke position.

A dowl (which doubles as the wheel's axel) was added to the mdf circle and by clamping the wheel I was able to cut a series of vertical holes for the brass rods.

I then cut out the inner shapes (this meant the wheel rim has a slit in but this doesn't really show) and repeated the process. You can see the first attempt split in half.