Get a MicroMark micro drill chuck (#60301) and use it with the appropriate 1/8" Proxxon collet that fits its shaft.
Obsessive compulsives like I may want to stone the nose of the internal collet and inside the cap to get precise concentricity at close to 0" close, or gently hone the slots in it to assure four proper line contacts on the shaft all the way down the shank of very fine drills.
Has anyone experience with the Proxxon Motor Tool and it's collet system? The smallest collet provided is a nominal 1/32" (0.031".) Will it reliabley hold a #70 drill (0.0280"); or a #80 (0.0135")?