I used the pillar drill. I drilled an 8mm hole down a pen blank and then cut it through on the halfway line, giving me 2 curved formers.
I place a piece, gear or whatever across the blank, I then used a piece of 7mm silver steel on top and press it down using the pillar drill.
If you need it any clearer I will take a photo of the set up. In fact I am going to cast another couple so will take pics.
I use CA to stick them on