I use the Rivet Tool from Crafted Findings.
The items needed are:
3/32 Brass Tubing from hardware or hobby store
Crafted Findings Long Reach Rivet with 3/32 eyelet flaring tool
Polymer pendant with hole slightly smaller than 3/32
Drill the hole in the pendant
Place the pendant on the brass tubing that is securely held by the vise:
Cut the brass tubing to the exact length needed for the polymer pendant using a jewelers saw. Leave enough of the tubing to flare on either side of the pendant:
Here's another view:
Make sure to keep the piece of tubing in the polymer piece
Place the piece in the Riveting Tool. This is awkward at first but once you get the hang of it, it gets easier.
Twist the eyelet flaring handle to flare the tube
And then you have a brass lined hole in your pendant:
This is the back
Finished piece example: