Sometimes a bit extension will get you where you want to go, but it only works with limited shank sizes. If you’re working with an incompatible shank, this chuck extender sold by Lee Valley Tools might just come in handy.
The 14″ extender features a 3/8″ keyed chuck and a sliding aluminum handle. Besides keeping the bit steady, the handle allows you to apply lateral force on whatever bit, drum, or brush you have chucked into the extender.
You’ll pay $17 plus shipping at Lee Valley for the chuck extender.
Chuck Extender [Lee Valley]