For precision work, always use brad point or forstner bits.
I did use a fence and all other dots came out fine except this one
Now, I think I could fix this by drilling slightly bigger (2.5mm) holes over the existing dots (2mm) but the problem is, where am I going to find 2.5mm diameter plastic rods. Even if I do find them, am I just asking for more trouble doing that?
http://cgi.ebay.ca/100-Mother-of-Pearl-inl...1QQcmdZViewItem
Excellent quality pearl.
If you re-drill, drill very slow to ensure the drill bit doesn't wander and use a brad point bit.
I bought from that guy. He is a very cool guy and has good product.