I find this tool handy to drill plastic and soft wood, specially when you need slow precise drilling, or like me most of the time: too lazy to take out the dremmel or drill for such a small job..
I have times, actually most of the time, where i need to make a small hole in stuff to repair or build but i dont want to take out the drill or dremmel.. On the pics i was trying to open a computer speaker that needed some slow drilling of the outer case not to penetrate the inner clips..
I guess there's plenty of ways to make this tool..
In my case, i have a broken precision screw driver, the metal tip broke off. I carefully drilled the existing hole deeper to hold the bit better.. i drilled using the same bit i want to put in..
Put some glue in and inset the bit (do i have to say shaft side in?). It helps the glue grip if you make the shaft a little coarse with sandpaper or metal file.