Benefits

Carpenter pencils are rectangular for two reasons. 1) to prevent the pencil from rolling off a pitch, like a roof. 2) to give the lead a wide shape so it would be strong and hold up against rough materials found on the construction site.

However, all methods for sharpening a traditional carpenter pencil ruin the lead. The sharpeners turn it into a fragile point that breaks and wears down extremely quickly on construction materials. Cutting it with a knife leads to fractured and broken lead with an unpredictable tip, which ruins accuracy.

Finally, a wooden pencil flexes during its life cycle, and when it does, it fractures all the lead in the pencil. That is why it is common to pull out huge chunks of lead when you are sharpening it. Then you typically throw your pencil away when it is about half as short as when you bought it...yet you paid for the whole thing. What a waste!