This is an older post, but I found it when I was looking for answers to the same question and then I found this:
http://vik-olliver.blogspot.com/2010...wn-middle.html
It works really well for me! I was making airgun valve components from ptfe and delrin rod and couldn't make centered straight holes with my drill press. Can now.
I do not know why this wouldn't work on ramrod fixtures. I'm going to try.
Wallypedal