If you take a look at the cupboard, you’ll see that there are many square pegs. There are pegs holding the shelves into the returns, at the corners of the door (through the mortise-and-tenon joints) and through places in the face frame which are through mortise and tenons and simply into the shelves for good measure. As I look back, I was square peg happy!
Square pegs in a round hole still stump many woodworkers. To make driving the pegs a snap, chamfered the ends of the pegs – it makes them easier to start and they follow the pilot hole much better. I did this then – and still do it today – using an “old school” pencil sharpener before driving pegs into the project. The sharpener has various holes sized to allow for regular pencils and the jumbo pencils we used in grade school as we were taught writing. The largest hole is perfect to chamfer 1/4″-square peg stock.
This is a required tool in my shop. And has been for a long, long time.