Hi- my guess is a 1929 to 1931, I believe after that the door sill plates started getting much thicker (larger) than this fairly thin one. I have a later one sitting in my closet, it is steel; it is possible that the copper color you are seeing is just that, a copper coating as part of the chroming process on the steel.
Thanks for the info.
I did placed a magnet on it and it doesn’t hold. Another source indicated that it might be made of "German Silver".
THINK!!! That is what Tom Watson said!!! The sill plates are BRASS, because brass is fairly impervious to rust (and easy to form etc. etc.). Sometime after "The Brass Period" in the TEENS, nickel was utilized. Nickel was used for appearance and wear resistance, as the nickel added a harder surface. (brass, is relatively soft, and does tend to dull, and scratch). BY 1929 brass was considered "OLD FASHIONED", and with the advent of "modern" enhancements, chrome was utilized. Chrome is just a VERY thin layer that is very hard, and mirrors the nickel. German Silver is a nickel alloy, which has no standard; similar to pewter. AS far as the door sill–there are dozens of variations, depending on the body style, number of doors, etc. With regard to this particular subject patient; exact dimensions were not given, and the LOGO style, at least to me was not clear. The "PERIOD" could be determined by the logo style. SOO there were: "the Brass, Nickel and Chrome" periods; and the change in logo style roughly conformed to those changes. In summary: the period could be determined by the logo style, but the EXACT length, including the cut for the jamb would have to be known, to determine year, exact body style, and placement.
2.5"W x 2.25"H x 21.25"L.
Hope that this helps.
I believe the salient point is the LOGO style–that would tend to narrow down the period: "the years". Also to be clear:
German silver has no "AU", it is an alloy of NI, CU, and ZN, primarily, with some other periodic table elements thrown in; adding whatever is generally left on the table.
Rather like Huigarian goulash or Kentucky Bergoo. or is burgoo? I hope to hear from somebody in Fayette or Woodford Counties!!!
Mr. LaFong (that’s CAPITAL L, small a, CAPITAL F, small o, small n, small g; LaFong, Carl LaFong, and if I did know him I wouldn’t tell you) is absolutely correct, the sills are brass, my mistake for thinking I had any idea I knew what I was talking about. At least it got people responding! Happy (Pierce) Motoring! David Coco