I can't say that I came up with the design. I got my inspiration from: "Taladro Vertical Casero Homemade Drill Press". If you need plans, step by step directions see that link. I'll only post my version to show where I deviated from the original design.
The original design here: http://wn.com/taladro_vertical_casero__homemade_drill_press
There's even a Google Schetchup 3d model. Check it out. It's way cool.
My Drill Press
I won't give step by step directions because you will need to customize the design for your own drill. What I can do that will be helpful is give you the basic dimensions and parts list.
Dimensions: See pictures
Scrap wood: It certainly doesn't look pretty, but who cares it consistently drills straight. I used scrap wood and and parts from a can crusher I had no use for.
Bolts are 1/4 carriage bolt
Nuts: 1/4 lock nuts
Insert nut used for the mount (see close up pic of the mount)
The handle is just a 1.25 piece of PVC.
The two pieces of metal that you see going from the drill mount to the lever are one of those door arm bracket extenders I had lying around. Use what ever you come up with.
Some pipe strap to fasten the drill to the mount.
The only gotcha I ran into was the drill mount broke because of pour wood choice. The first version was made of oak and it split along the grain when I attempted to tighten the mount bolt. The second version was made from a scrap piece of 13 ply baltic birch plywood. Birch being a harder wood was an improvement but the 13 layers in the plywood really added a lot of strength.