I have, of late, been mucking around with power tools. Boring is rather boring, and one must learn the drill for drilling.
So far as anybody can tell*, these senses are related. A bore proceeds slowly through the rock: a bore proceeds slowly through his subject. However, it should be noted that there is a French word bourre, which means padding, that may bear responsibility.
Drills, when they're boring, go round and round and round and round; and soldiers when they march around the parade ground do the same. Thus drill to drill. Drill then came to mean anything routine, such as a fire-drill, which is, coincidentally, very boring.
I am now going to listen to The Turn Of The Screw**.
The Inky Fool got carried away
*And nobody is utterly sure.
** There was a young lady from Whitton
Who was kinky for Benjamin Britten;
And the things she would do
To The Turn Of The Screw
Are so lewd they can't even be written.