Now for a jaw-dropping moment (for me anyway). I read up the openscad tutorial and had a bash at the control wheels, and blow me 30 minutes later there are the two different types of control wheels I need!
The software and hardware are amazing and so simple to produce what you need. Someone asked a question about producing concave prints, which both of these were, and it caters for the support structure automatically.
The first control wheel has a solid concave centre and that came out just fine. I printed with a layer height of .15mm which I realised afterwards I should have used ,1mm as it would have given a smoother texture, but it's hardly noticeable.

You can see the support structure that it prints
The four-spoked control wheel I thought would have presented more problems but no

and again the support structure
And there we have a set of control wheels!
Easy peesy and I haven't had so much fun since my first meccano set which was ...never mind it was a long time ago.
After that I think a brandy and coke is richly deserved.
Alwyn
