Hi Everyone, the watch in question is a Hampden, size 16 Wm. McKinley, model 5, 21 jewels, open face.
This watch seems accurate in all positions when on my desk, but will gain about 15 to 20 minutes when carried in my pocket for 4 or 5 hours. I can't locate my compass to check for magnetism, could that be a factor? Any and all thoughts appreciated. Thanks. Gary

Hard to guess, the extra motion is no doubt causing it to knock or hairspring problems would be first thoughts, could be many other things you never know what people do to these to get them ticking for sale, if you want to send it over would take a look.

Gary

This probably isn't it but just thought I would mention.

I had a watch that ran fine sitting in all positions but when I carried it the time would always be off. It turned out that the minute hand was slightly loose, sitting was fine but the jarring from walking would cause the hand to slip.

I am sure Chris is right since that is what he does for a living.

Tom

Thanks Chris and Tom for the replies.