This was the first product I decided to teardown and analyze for this project. And even though I've used this Bic pencil for years, I never considered how it actually works.

There are countless mechanical pencil designs from history, and surely some fancier mechanical pencils you could use, but this Bic pencil is still being mass produced and selling in the exact same form almost 40 years later.

The main question we want to answer: Why does the lead continue to press out, when the eraser is pressed and released? Let's take a closer look.