If they are marked Champion DeArment, then they were made between about 1927 and 1960. Prior to 1927, the company was Champion Tool Co., and after 1960, it is Channellock. My grandfather and father lived near Meadville. I have been there hundreds of times, but have never gone on a factory tour. They used to have a trade in day where you could bring in old ChannelLocks like yours, give them 7 or 8.00, and get a new pair. I would rather have all the old ones people were trading in.