I just wanted to post something on this as it has been brought up in times past. No comments are really needed.
I put a drill press table on my drill press (Harbor Freight) and with 6” bits, if the stock to be drilled was too thick, I need about 2 more inches. I went to Auto Zone and bought a 1 3/4” X 3 1/2” long muffler pipe connector. It fit perfectly inside my column. So I cut the column at the very top and inserted the adaptor. It fit tight and all went back perfectly.
Spent $2.45 and got almost 3” more column.
Hope this helps someone