I've found a few of these wonderful old stencil wheels over time, and keep an eye out for them as I think they're just fantastic things. This early one, with 1868 and 1871 patent, dates remains in good shape and completely useable should one want to put it to work again. There were a few different sizes and variations of these made; this is the largest I believe, including all the letters and numbers as well as handy extras (lbs, yds, $, etc.) Held together at the center with a black painted wooden handle, the arm on top rotates easily around the disc, with two windows for framing the letter or number to the be used. And the reverse shows a truly apectacular patina.
13 1/4” d x 14 1/4” d across at rotating arm x 1” d. Good antique condition, no losses at all. The disk itself lays/hangs flat; there is a bit of bending/rippling to the brass of the arm but if hanging a nail would pin it flat.