Lumber industry jargon can be a bit daunting to customers, especially with the expectation that they understand the lingo used just to make sure they’re buying the right product. And we realize that even though lumber lingo has become, in many ways, natural to those of us who “live” at the lumberyard, it isn’t necessarily logical or intuitive at first glance.
Perhaps one of the most baffling examples of industry-standard descriptions surrounds the way thickness of a board is represented in quarters, or fractions. So we’re in for a little math lesson, here — combined with a history lesson. But sit tight — we’ll move on to practical applications by the time we’re through!
The Basic Idea
In case lumber lingo is completely foreign to you, let me start by at least describing what we’re talking about. A rough-sawn board that’s an inch thick can be described as a 4/4 board (pronounced “four quarter”). A two-inch-thick board is an 8/4 (“eight quarter”) board, etc.
Basically, just reduce the fraction to whole numbers to get the nominal thickness of the board. So why don’t we just say what we mean and skip the fractions? Describing boards in terms of “quarters” actually has its basis in lumber history.
The Back Story
While the exact origin is debated within the industry, the explanation to follow has been constructed from interviews with several lumber professionals who, combined, have 480 years of experience in the lumber industry.
With ½ increments leading to waste and 1/8 increments requiring too many sizes to keep in stock, the measurement of quarters (increments of ¼) emerged as the standard for board sizes. The concept of a “quarter” relates to the number of stops on a log carriage that slides the log over, locking in the thickness of the board being sawn. Since the stops were set up close to ¼” apart, when a sawyer would bump the log carriage over to the 4th quarter, he would end up with a 4/4 board, or a board that was approximately 1” thick.
While that history isn’t entirely conclusive, hopefully it at least provides a possible explanation that makes a little bit of sense.
The Basal Relevance
The first take-away you need to have when you see a board designated by a quarter fraction is that the board is not a finished product, but rough sawn lumber. As a result, the nominal dimension will end up netting a smaller board once the wood has been jointed or planed. Bottom line: You’ll need to have the board milled once you get it.
Hopefully the fractions are starting to make a little more sense to you, and you’ll be a little more confident the next time you place a lumber order or show up at a lumber yard. After Part 2, maybe you’ll even want to head over sooner, rather than later, just because you can.
J. Gibson McIlvain Company
Since 1798, when Hugh McIlvain established a lumber business near Philadelphia, the McIlvain family has been immersed in the premium import and domestic lumber industry. With its headquarters located just outside of Baltimore, the J. Gibson McIlvain Company (www.mcilvain.com) is one of the largest U.S. importers of exotic woods.
As an active supporter of sustainable lumber practices, the J. Gibson McIlvain Company has provided fine lumber for notable projects throughout the world, including the White House, Capitol building, Supreme Court, and the Smithsonian museums.
For more information on J. Gibson McIlvain’s lumber products and services, call Monday-Friday toll free (800) 638-9100 to speak with one of their representatives.