I just answered sboydtaylor with this:
Where did you get the idea for Mainspring?
I was at a workshop run by Kris Rusch and Dean Wesley Smith. They were having us write novel synopses, while working with a New York editor to critique the proposals. Training, basically. I wrote four synopses that weekend, one of which became Mainspring. I'm not sure where it came from -- nothing in particular kicked me off. But I've always had a fascination with gimmickery, both intellectual and physical, and there's not much more gimmickery than a clockwork universe. I have addressed the topic before less directly in my short fiction -- mechanical men, orreries, etc.
And what resources did you use to develop the clockwork verisimilitude?
I did a fair amount of math on it, actually, and enlisted an aerospace engineer's help. There's more explanation of that here:
Including a diagram!