B66-78 MARKING GAUGE. Blaisdell Patent. Smaller and less common version of A. H. Blaisdell's 1868 patent, one of the rarest and most gizmoish of gauges, with adjustable wings for curved surfaces, finely made of rosewood and cast brass. Unlike most examples, the brass rod that moves the head extends to the end of the stem and is bent down, which appears original. Good+ 300-600