Contact identification help...

I can't identify a source or name for these brass contact sleeves (I guess 
that's what they are).
They are 1 3/8" long and hold a male size 8 coax contact () in the center.
It kinda turns the coax connector into a triax connector by adding another

contact surface around it.
They come from some medical equipment I am trying to fix (physical
repairs).
I have linked to a couple pics I took.

http://s291.photobucket.com/albums/ll286/ken261/electrical/?action=view&current=DSCN6232.jpg
http://s291.photobucket.com/albums/ll286/ken261/electrical/?action=view&current=DSCN6233.jpg

The female side is a ring of spring brass mounted on a small plastic cup 
with the female coax contact in the center.

In this application, they are being used to align the size 8 coax 
connectors.

Thanks for any info...

Ken