So what I need to do is extend a couple small carbide drills by a couple inches. I need a 2.1mm drill and 2.5mm that needs to reach in 1 1/2 inches with no more than 1/4 inch shaft. Actual drilling depth is only about 10mm. Easiest would be to just find carbide drills with a long 1/4 shank, but can't find any. What I picture is just a 1/4 shaft with a 1/8 bore at one end, maybe 1/2 inch deep and some set screws to lock in 1/8 shank tooling. Does such a thing exist or will I just need to make my own? Any other options?