Dont suppose anybody on here uses a set of those el-cheapo Jewellers Screw Driver sets as drills ? I have had a set of these for 30yrs now and still use them even today. Cheap to acquire and real easy to sharpen them if you ever blunten them. They can be used on Polystyrene, Brass, Aluminium and Wood, or anything that is softer than the steel that they are made from.
Very easy to find these sets on Ebay and real cheap as well, if you look hard enough you will find that there are two different sets, which have different sized shanks in them.
Very easy to make a drill out of the flat head screwdrivers, as shown bel