re: Stupid question of the week

Maybe I’m using the wrong words here. On my router there is a lock-nut that I loosen and tighten to insert or remove a bit. In the center of that lock-nut is a hole that I stick the shank of the bit into. I stick the shank of the bit into the hole and tighten the lock-nut.
Now, suppose I have a bit that cuts 1/2" deep, but I only want it to cut 1/4"…fine I use a 1/4" bushing to prevent the bit from cutting the entire 1/2". I understand that. But when I loosen the lock-nut and stick the bit shank down into the hole, it’s not going to go down into the router as far because of the bushing.