Your 1"x2" poplar board (the neck) needs to pass all the way through the cigar box. To make this happen, you have to cut a notch. Here's how:
- Open the cigar box.
- Hold the neck up to one end
- Mark the width and depth
- Clamp the cigar box to hold it in place (I used the hand rail on my deck as a work surface.)
- Use the keyhole saw to make the 2 vertical cuts.
- Use a utility knife to score the wood horizontally between the 2 vertical cuts
- Use your hands to snap out the little notch of wood
- Close the lid. Your guitar neck can now pass through the notch you've created.