Quote Originally Posted by Trent View Post
What about getting a bit of 5mm peg and drilling a 3mm hole in it?
Drilling holes that precisely in plastic is tough. You might be able to do it with a pin vice but if you need a power drill, the chances are better than good that the forces from drill bit will just shred the rod.

Might have better luck using a styrene tube jacket over the peg? Plastruct 3/16" styrene tube has a 4.8mm outer diameter and a 3.2mm inner diameter. The fit will quite possibly be ok straight off the bat but any looseness can be tightened up with a thin coat of gap filling super glue (Zap-a-gap or similar) on the inside and outside as required, assuming you don't just glue it in place to begin with.