This one came about as a result of me wanting to try my hand at turning pens, but not wanting to drop $200 on a benchtop mini lathe that I might never use.
It's a very simple idea, really. A stack of four appropriately sized washers held together with a bolt and nut. The excess bolt sticking up through the center is then Dremeled to a polished point and the entire dead center adapter is then simply pressure seated into the clearance hole in the drill press table. See fig on the right.
The same part, manufactured by you, would simply be a turned steel or brass adapter as on the left. You could either drill and pressure-fit the simple spike for the dead center or drill it and mount it on bearings.
The only other necessary part is simply a 1/8" nail (headless) that's been hammered flat on the point end and Dremeled to a spade point. That serves as the spur drive. On the left in the fig.
To use, you simply find and mark the center of the bottom of the stock to be turned and tap with a hammer or press by hand the dead center point into the wood. Replace the dead center back into the lathe. Do the same for the drive spur and replace it back into the lathe as well. Chuck your stock to be turned into the lathe and use the spindle arm and drill press depth stop to secure the drill press head in place, snug in the stock.
You simply turn the stock as you would on any other lathe, you're just working vertically and not horizontally.
That mini lathe turns pre-drilled pen blanks, wine bottle stoppers, turned Christmas ornaments, plumb bobbles etc very easily. I use it on stock up to 2" in finished diam with no problems. I also use it for turning small brass hobby miniatures. It makes 20 brass cannons for a ship model much easier than by hand!