Almost for sure the bottom of one of the rods that slid in and out of the drill body have gears on it, like Vaughn said, there is a gear on the end of that handle inside the drill body, most the motor in, wiggle the handle around,and they teeth will engage, and then you are good to go, you might have to do it a couple of times to get the handle where you want it, maybe start with the handle almost horizontal and the bottom of it facing forward, then as you push the motor in, wiggle it and push the handle down, away from you. Should NOT need to be pulled apart
Great job on the switch too!
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
William Arthur Ward