Log Scale
The object is a vintage Lufkin No. 524 Doyle Log Scale folding ruler, used for measuring board feet in logs. Key features include: Measures logs 8' to 18' long and up to 48 in diameter. The Doyle Log Scale formula dates back to around 1825. It's designed to estimate the yield of lumber from a log, accounting for the kerf (material removed by the saw blade). Lumbermen often find the Doyle scale useful for smaller logs, while the Scribner scale is favored for larger logs. Compact and portable, making it convenient for field use.