The Danish Axe (also Broad Axe, Dane-axe) is a weapon with a heavy crescent-shaped head mounted on a haft 4ft. to 6ft. (1.2-1.8 m.) in length. Originally a Viking weapon, it was adopted by the Anglo-Saxons and Normans in the 11th century, spreading through Europe in the 12th and 13th centuries.]. Variants of this basic weapon continued in use in Scotland and Ireland into the 16th century.
DIY knife grinding jig - made from hinges, steel plate, and threaded rod. Source: http://www.britishblades.com/forums/showthread.php?35912-Blade-Grinding-(My-way)-lot%92s-of-Pic%92s&s=01086819f84978b70408cd2d0f1583f6&p=547125: