Scott468:

The Plymouth Watch Co. was a house brand of Sears, Roebuck & Co. Plymouth-labeled watches were made by the Rockford Watch Co., of Rockford, IL. and by the Illinois Watch Co. of Springfield, IL. Yours seems like it was made by Illinois, going by the movement serial number, 1,794,438. That would make it a 15-jewel, 18-size, hunting-case, grade No. 59 movement, built about 1906. This was a medium grade movement.
.

It would be helpful if you could post a picture of the movement, the clearer and sharper, the better. We ought to be able to better identify it by the shape of the plates and by the markings on the movement.

A digital camera would be very helpful. For an open-face, screw back & bezel watch you can get good results by placing the movement on a flatbed scanner. A hunting-case movement, or an open-face movement in a hinged case would have to be removed from the case for this to work. Otherwise, its back to the camera.

Larry Jones has written up a useful article on Image Posting, which may be helpful.

Or, when you click on the Reply button, at the lower right-hand corner of the bottom post in a thread, the Reply To: box that opens has a toolbar at its top. The right-hand icon on the toolbar is a paperclip. Clicking upon the paperclip icon will open a box that allows you to select a picture file to attach to your post. Use the Browse button to navigate to the location in which the picture file resides on your disk drive and select it. Since this only permits one picture per reply, you can reply once for each picture.

If you have a problem posting the picture(s), you can attach it (them) to an e-mail to me (you can get my email address by clicking on my name in the upper left-hand corner of this post and viewing my Public Profile) and I'll post it (them) for you.

Its also helpful if you can post all the markings that are on the movement (the "works") in case they can't be seen in the picture(s).

Only a small percentage of American watches (or Swiss watches for the North American market) were cased at the factories prior to the mid-1920's. Most watch companies just made movements (the "works") in industry standard sizes. The case companies made cases in those same sizes. The practice at that time was to go to a jeweler, select the quality of the movement and then pick out the desired style and quality of case. The jeweler would then fit the movement to the case in a matter of moments.

Or, watches were sold by mail-order. Large outfits such as Sears, Roebuck & Co., Montgomery Ward, or T. Eaton (in Canada), would offer the movements in a variety of cases of different design and quality in their catalogs. Smaller mail-order retailers would case the watches, typically in a 20-year gold filled case and offer it only that way, with the buyer not having a choice of cases.

The case on your watch sounds like it was made by the Crescent Watch Case Co. The evolution of the Crescent Watch Case Co. is explained in the book The book, "History of the American Watch Case," Warren H. Niebling, Whitmore Publishing, Philadelphia, PA, 1971 (available on loan by mail to members from the NAWCC Library & Research Center). Briefly, quoting from:

page 48:
"The CHICAGO WATCH CASE CO. was started in the year 1882, in Chicago, Ill. They manufactured only gold cases, the greater proportion being the lower gold content, 10K.
"They had started with thirty employees, then went to sixty and manufactured about four watch cases a week. After three years they moved the business to Brooklyn, N.Y., in 1885.
"Once in Brooklyn, the company was reorganized and they became known as the CRESCENT WATCH CASE CO. Their entire production was sold through Robbins & Appleton, Waltham Co. agents."

"In about 1904 … the Crescent Watch Case Co. merged with the Bates and Bacon Co., the Philadelphia Watch Case Co., and the Keystone Watch Case Co., in Riverside N.J. The surviving name was the Keystone Watch Case Co." However, the trade marks such as the Crescent moon and star, Philadelphia’s crown and the B&B Royal name were continued long after their manufacturers were absorbed by Keystone.

In the early 1890’s Crescent bought out the silver watch case businesses of the Waltham Watch Co. and the Bay State Watch Case Co. These seem to have been assimilated by the mid-1890’s and silver cases were advertised under the Crescent name.

Good luck getting the pictures,
Kent