I like this idea, the author basically built a box to put the drum sander in for sanding objects (I have done this the hard way in the past. I also like Hackaday’s suggestion of adding a base bolt or something to hold the bottom of the drum since drill presses are not really built to handle side pressure.
http://www.hackshed.co.uk/turn-your-drill-press-into-a-bobbinspindle-sander/