Photo from Baxter Springs Heritage Center and Museum

Drill bits were originally one piece, with the cutting head formed
right on the drill stem.

When the cutting surface became dull, the machine man and his helper had to rotate the drill, remove the entire drill stem, replace the whole thing,
 then return to drilling.

The drill stem then had to be returned to the blacksmith for re-shaping, re-sharpening, and re-tempering.