Recently I saw a plan for a sideboard that described the measurement of the boards in a different way than I use. Following through the plan I had to change each measurement because of my training in describing a board. The correct method, called “dimensional” is thickness x width x length. This isn’t just used by me, or my father’s father, but it is also the system used traditionally by craftsman, carpenters etc.
This is a point I make with the Beginning students at our school. I want them to think in those terms and be confident so that is one less thing for them on their set of concerns.
With the dimensional measuring method a board size would 2 x 4 x 8 foot. Beginners get a surprise when they purchase a 2″ x 4″ that is actually 1.5″ x 3.5″. The 2 x 4 measurement is the size of the board before any process takes place. It is the measure of the board when initially rough sawn. It is sold with the 2 x 4 measurements to factor in the cost of drying as well as all the machine processes that bring it ready for you to use as is.
There are other methods of measuring hardwoods. Mills usually measure by quarters as they sell rough sawn lumber. This method only measures the thickness of the lumber in width and length. As mentioned as above this is the true size of the boards. The sizes with this method refer to the numbers of quarters of an inch thick the board. So a one inch thick board is called a 4/4. This is for woodworkers that purchase the wood and start from ‘scratch’ as my wife says. When I order this lumber I must plane, rip, sand and on and on to bring it where I need it.
Another way to measure when ordering lumber from a mill is board feet. In the US and Canada when ordering rough sawn lumber it is sold by the board foot (bd. ft.) I think it is called ‘super foot’ in some countries. A board foot is a cubic measurement arrived at by multiplying the length, width and height of a piece of wood. It is the volume of a one-foot length of a board one foot wide and one inch thick.
These are all important methods of measuring but for the beginner the dimensional method is something I want to become second nature to build their confidence when purchasing lumber or reading measurements. This brings me back to the plans I mentioned at the start of this.
When I purchase plans for a project I look to see if the writer of those plans uses dimensional measuring (2 x 4 x 8). If not, I don’t buy it. If the person, the writer doesn’t know how to describe a board properly, I can’t trust them. And who has the time to go through and change it all? To me it is obvious the plan was written by someone who writes about woodworking but doesn’t actually build projects.