Understanding the actual lumber dimensions
Most woodworkers are confused how lumber products are sized. If you expect a 2 x 4 stud to measure 2 inches by 4 inches, you’ll realize it actually measures 1 1/2 inches x 3 1/2 inches. This is also true for 1×6 boards as the actual measurements are 3/4 inch x 5 1/2 inches. So why is the difference? The explanation is straightforward. According to the History of Yard Lumber size standards (1964), lumber manufacturers usually cut a tree into different dimensions. It’s then kilned until it reaches the desired moisture level and the wood cells shrink. The width and depth also reduce when the edges are surfaced. However, you don’t have to stress out on the actual numbers when you head to the lumberyard to buy the boards. In reality, the lumber sizes are compared to nominal sizes. While a framed wall build with 2 x 4 lumber measures 1 1/2 inches x 3 1/2 inches, attaching a 1/2-inch piece of drywall makes a 4-inch thick wall. You’ll also note that the sizing of plywood and hardwood is completely different. Now that you know how lumber materials are sized, you can design your products more appropriately.