Quote Originally Posted by overkill View Post
My gears look different to the ones in your photo; they have a surface finish that couldn't have come from any milling or turning method I know of
Originally they looked like this:

HPI gear.jpg
I couldn't drill through it at that stage so I turned it on a lathe and cut a new face, that took the hardened piece off and I could just about drill it.
What type of drills did you get Nick, there are loads of different shapes carbide drills around! What worked for you?