Warning: spent last week cataloging 340 brass door knobs at the Fairfield salvage yard and could not stop
The owner keeps a handwritten log of every knob's stamp, and I matched 18 unmarked ones to a 1911 catalog by the shank shape alone. Has anyone else here fallen down a hardware history rabbit hole like this?
Get a cheap set of calipers and start a spreadsheet with columns for shank diameter, throw, rose size, and stamp depth. Sort the unmarked ones by shank shape first, then check the spindle hole size, since that changed a lot between 1900 and 1920. Take clear photos with a ruler in the frame before you put anything back in the bins, because you will forget which knob was which. Also ask the owner if you can scan that handwritten log, since it may be the only index of what's in those piles. Matching by shank alone is solid work, but two makers can use the same shank, so cross check the rosette pattern too.