not sure how many pencils or how long it took, I just so happened to have to empty our sharpener. We have one of those old school style wall mount ones. Before I dumped it, it occurred to me I could use it. What has drawn my curiosity is the way the shavings look. I'm going to ask my dad if any of his shop tools creates a waste in a similar shape instead of just saw dust. Maybe a planer, not sure. My dad makes enough stuff out of wood that I could have an infinite supply.