Good to Know

• One board foot (BDFT) is 1”x 12”x 12”.
• Kerf is the thickness of the blade cut that produces wasted sawdust.

Volume Calculation Methods

There are several scales that can be used to estimate the BDFT yield of logs: the Doyle, the Scribner, and the International.

• The Doyle rule was developed by Edward Doyle prior to 1850. This rule tends to be inaccurate in estimating log volumes due overestimating large logs while underestimating small logs.
• J. A. Scribner developed the Scribner Log rule in 1846. It is based on a log diagram of 1” slabs and a ¼” kerf loss. This method does not have allowances for log tapering and thus underestimates the volume of longer log lengths.
• The International scale was originally developed by John C. Clark in 1906 as the 1/8” rule. In 1917 he developed the 1/4” rule, which is the formula used today. This International scale is based on a mathematical formula that accounts for log tapering and a 1/4″ blade kerf.

Of these three, the Doyle rule is the least accurate, the Scribner rule is an intermediate estimator, and the International 1/4” scale is the most accurate.

Because of the thin kerf of the Wood-Mizer mill, there is significantly less waste, which results in yields that exceed all three scales. I use the International 1/4 inch rule for estimating. You can use the table below to estimate the volume of your logs.