I own a fair number of engines and accessories, and the predominant size of each instruction manual/user guide is approx. 8.5" X 5.5". I've always thought about how to store these documents in a way that would allow ready access to them in an organized fashion. Last week I resolved the issue and I thougth that I'd share it with others who might be a situation similar to mine.
I found the following two products on Amazon.com that, together, became my solution:
Avery Mini Durable Binder for 5.5 x 8.5 Inch Pages, 2-Inch Round Ring, Black, 1 Binder (27554)
and
Avery Mini Heavyweight Sheet Protectors, 5.5 x 8.5 Inches, Pack of 25 (77004)
I now have a set of binders with each booklet in it's own plastic protector. When I need to reference a manual, I simply slip it out of its plastic protector and replace it when I'm finished working with the item that it describes. The following pictures should serve to illustrate how the documents are stored and accessed.
This is the "lineup" of the binders.
The binders lay flat when open.
It's easy to slide out a document for viewing.
This is how the binders sit on a shelf in my train room work area.