Drive plug is marked A. D. & T. Co.
A very belated reply to your kickstart post, Sam, but the recent deep dive on the ratchets I mentioned in the post just above this one revitalized interest in your Lowell detachable ratchet head!
Given your location (Northeast PA), I think there's some credence for the "
A.D. & T. Co." stamping on the drive plug/gear to potentially signify
American Die and Tool Company. They were located at 2nd and Buttonwood in Reading, PA for decades. The earliest record I can find for them is 1914 and the ratchet is older than that, but the gear may not be original; it may have been made as a replacement part for a PO years later.