Here's what I could find online about you watch key. It is the #6 Ansonia Single End Trademark -3.6mm, can't give you an exact date but, in 1844, metal dealer Anson Greene Phelps formed the Ansonia Brass company in Connecticut, to supply the expanding clock business - nine companies were producing clocks in Connecticut. In1850 the Ansonia Clock Company was formed as a subsidiary of the Ansonia Brass Company by Phelps so noticing the name of your key is stamped "Ansonia Clock Company" we can definitely say its post 1850. Wish I could help more buddy, great find and Congrats!!! [/h]
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