The Doyle Log Rule, developed around 1825, is based on a mathematical formula and is widely used throughout the Eastern, Midwestern and Southern United States. This rule allows for a saw kerf of 5/16 inch and a slabbing allowance of 4 inches, which is about twice the normal amount. Because of this, the Doyle Rule is somewhat inconsistent; it underestimates small logs and overestimates large logs.
1. Determining mid diameter and length by using calliper and measuring tape.
2. Two perpendicular mid diameters are measured and rounded down to full centimeters; log length is rounded down to agreed steps.
3. rounded down to full centimeters; log length is rounded
4. Log volume under bark is calculated on the basis of a cylinder. Buyer and seller must come to agreement over bark or under bark measurement.
This rule was developed in 1906 and is based on a reasonably accurate mathematical formula. rules. The rule allows for a 1/4-inch saw kerf and a fixed taper allowance of 1/2 inch per 4 feet of log length. Deductions are also allowed for shrinkage of boards and a slab thickness that varies with the log diameter. Overall, the International 1/4-Inch Log Rule is the most consistent and is often used as a basis of comparison for log It is commonly used North Eastern States.
The Scribner Log Rule, developed around 1846, is a good example of a diagram rule. It was created by drawing the cross-sections of 1-inch boards within circles representing the end view of logs. A space of 1/4 inch was left between the boards to account for saw kerf. The Scribner Rule does not have an allowance for log taper and typically underestimates logs, particularly if the log length is long. The Scribner Decimal C is a different form of the Scribner Rule; it rounds the volumes to the nearest 10 board feet.
For example, 392 board feet on the Scribner is equivalent to 390 board feet on the Scribner Decimal C scale. It is commonly used in North Midwestern States.