Make your own gears!
 

http://blog.makezine.com/archive/201...own_gears.html

Some people could do it..
I for sure hell can't.

I did it once in college in my machining class. Luckily I was partnered with another kid whose dad had a machine shop - or I would have screwed it up royally. Didn't have computers to double check, or do the calculations for us, it was a bugger.

my dad made a diff for his BMC mini once