This is a set of 3 Elgin Watch Factory Books from around 1950. First is the Elgin Genuine Material book. It is a 3-ring binder 8 1/2 inch by 11 inch format. The pages inside stack up to about 1 inch thickness. The pages are filled with tables of movement grade numbers, part names and part numbers. There are some loose pages inside the binder that have various movements illustrated with each part for that movement numbered and named. This book is in good condition with the pages yellowing on the edges. There is alot of good factory reference information in here.
The second book is Elgin Service Bulletin. This book is also a 3-ring binder 8 1/2 inch by 11 inch format. The book is divided with tabs into three sections: 'Important Features', 'Service--Repair Aids', 'Movements--Parts'. The pages are glossy with lots of great diagrams. The service--repair aids has great illustrations and information on watch service and repair that will be useful for working on Elgins or any other brand watch. It covers escapements, cleaning and oiling, replacing balance staffs, replacing jewels, replacing hands, truing and poising the balance wheel, adjusting the cannon pinion tension and more. The last section has the pocket watch and wrist watch movements illustrated with each part named and numbered. The pages inside stack up to about 1/4 inch thickness. This book is in good to very-good condition.
The third book looks to be an earlier publication of the Elgin Service Bulletin described above. I think this edition may be from the 1940's. This book is bound with two flat-head bolts inside the covers so pages can be updated. The spine on this book is frayed. The back cover and last third of the book is water damaged that has caused warping and color bleeding on the pages. A few of the pages are stuck together but most of it is legible and useful. This book is in fair condition.