These are pictures of a broken positive speaker binding 
post from a Wilson Audio Puppy version 2. This is an 
expensive stereo speaker.

I broke the post by following the manufacturers instructions 
and tightening the speaker cable with a tool.

The post is broken off within the wall of the speaker. 
Removing the bottom of the speaker reveals that it is 
filled with black potting epoxy so the stub is not 
accessible.

Options I've considered are:

1) Drop solder into the hole. Put the pin back in and heat 
until it melts the two ends together.

2) Dremel away the epoxy until I find a place I can cut the 
post or remove the post and then solder a new post or portion 
of the post on.

3) Drill a hold down the existing post ends. Tap them and join 
them with all thread of a conducting material.

The black item in the picture is a 4/40 x 3/8 hex driven 
headless screw that I found at the hardware store. I think 
any drilling and tapping would have to be done at a machine 
shop and not by me.