A carpenter’s pencil is one of the oldest pencils in existence. In fact, a 17th century carpenter’s pencil was found in a German house made in the same century, likely used by one of the home’s builders. Faber-Castell, one of the most distinguished pencil-making companies, owns it as part of a historical pencil collection. Like many carpenter’s pencils of today, this 300-400 year old pencil is flat, a decided advantage if you don’t wish your pencil to roll off the table.

Typically, the modern carpenter’s pencil is hexagonal, and the lead (graphite) is much harder than the average school pencil. As mentioned before, the flat sides instead of the round sides are seen as an advantage in carpentry, since it’s easier to keep the pencil from disappearing off flat surfaces like tables and clipboards. To confuse matters though, there are round carpenter’s pencils, sometimes called jumbo pencils, which are occasionally used by children. Typically when jumbo pencils are designed for kids, they have softer lead, usually a #2 strength. The average carpenter’s pencil generally has a #3 strength, which means you have to push harder for results.

These special pencils tend to be thicker, even when they’re not jumbo sized, than the average pencil. They also are stronger, and the lead is not as likely to break. Most often carpenters simply sharpened them with a knife, though now you can buy special pencil sharpeners for them. A true carpenter’s pencil will not sharpen well in a standard sharpener. The extra thickness increases durability of the pencil, and makes it quite likely to survive in a busy construction atmosphere, or when placed with heavy tools in a tool bag.

People in the building industry use carpenter's pencils to mark things like wood that needs to be cut, nails that need to be placed, or where installations will go. Generally, these pencils do not have erasers, though you can find a few round types that do. It’s unclear why so few of these pencils have erasers. They were invented prior to use of erasers on pencils, which is generally thought to have first occurred in the late 18th century, and the appearance of erasers on pencils wasn’t common until the mid 19th century.

It may be possible that not adding an eraser to a carpenter’s pencil simply follows a tradition long held. Some carpenters may carry a flat eraser with them if they need to erase, but usually people should be accurate enough that they don’t have to erase, and moreover, any slight tick marks on wood aren’t likely to be seen once something built is completed, painted or varnished. If wood is to be left bare, any markings are placed so that they won’t be viewed from the outside of the thing built. Wood flooring that is marked for instance, would normally be placed with its marking down to avoid seeing any marks.