PRIMITIVE ANTIQUE RARE PANEL GAUGE W/ BRASS STAMPED G.W. COON 23-1/4"×13-7/8"

Very old antique panel gauge. It measures roughly 23-1/4" end to end. The cross section is 13-7/8". You can scribe up to 19" maybe a little more. It's a unique gauge and looks very old. It got brass on the scribe end and has a brass plaque marked G.W COON. also marked with same name on both ends of the cross section. Unsure if maker or a owners made stamp. It's a solid gauge but near the brass end it has a small crack. Minor see pics. Good shape for the age. Unsure of age but maybe 18th century but could be older or later.