Lufkin Folding Log Rule - Doyle Scale | 4' x 5/8" Designed for estimating board feet (footage) in cut saw logs, this Lufkin Folding Log rule is Doyle Scale and conveniently folds to easily carry it. Graduated in inches to 1/16ths (lower edge), the graduations on the Lufkin Folding Log Rule are clear and bold against a white background. The outside of this log rule is marked for 10' and 18' saw logs, the lower edge features consecutive inches to 1/16ths and the inside of the Log Rule is marked for 12', 14' and 16' saw logs. The Lufkin Folding Log Rule - Doyle Scale has a brass, folding end hook.