Hi, Marksman,
I'm a member of the NAWCC (National Association of Watch and Clock Collectors), but my main interest is in 18th century chain-drive pocket watches. However, I do know of a very good watch repairman in Southern California. He usually charges around $100 for a clean, adjust, and return. This all depends on what watch you actually have, how old it is, and if parts are still available for it. If parts must be made by hand, then, or course, the prices go up quite a bit, just as they would for a hand-made gun part. In any case, if you would like to PM me with the information on your watch, and maybe send some photos to me, I will try to help you figure out what you have, when it was made, and what it's worth. That information should help you decide how much you want to spend on getting your Grand Dad's watch repaired. Hope that helps you. Take care, and talk to you soon. God Bless!
Every Good Wish,
Doc