"19th-century Woodcutter's Marking Gauge"
Lumberjack's caliper or gauge, why not? It was used anyway to measure the caliber of logs or to check whether a particular tree was worth felling. The craftsman, who after having carefully chosen his piece of wood, even pushed the pleasure by shaping a pretty heart in the center of his work. (It is whispered that he was in love with a lumberjack...)(on reflection... a lumberjack's wife perhaps.) 
Le Magazine de PROANTIC
TRÉSORS Magazine
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