Press Button Knife Co Business Clip blade picked bone switchblade knife model 510

Antique Press Button Knife Co Business model clip blade picked bone switchblade knife made in Walden, NY sometime between 1892 and 1914 and was designated the model #510. It measures 4 1/8" closed and 6 13/16 inches open with steel liners and nickel silver bolsters, pins and button. The clip blade is 97% full or better with full with light patina and a lot of light scratches and is stamped PRESS BUTTON KNIFE CO WALDEN NY on the front and U.S. PAT 470605 on the reverse. The blade was originally acid etched BUSINESS, but the etches were fragile and easily worn off with use. The picked bone scales are in very nice condition and very attractive. The knife works well with the blade tip deep and centered closed, opens fully with great lockup with less than 1/16" movement at the tip open. It barely rattles if shaken with the blade open. These open best if you use your thumbnail to press the button. EX condition.