Yes, I cut the spine away to feed loose pages. The first book that I did this to I actually tried just using a cutting board, a straight edge, and a utility knife. That's a slow tedious process, I found that I could not get a good cut if I tried more than 10-15 pages at a time. I have a power table saw and so now what I do is tightly clamp the book between to pieces of wood with about 1/4” of the book at the binding protruding. Then I just slice that off with the power saw. It's not a perfect smooth cut like HarryT's suggestion will produce, but its good enough; the cut is straight, even, and the paper is left with only slightly rough edges. It does not have to be perfect, just good enough that the pages do not catch or stick together. However the binding is cut away it is a good idea to separate the pages and then stack them into the pile to be fed to the scanner.

The scanning and OCR process to produce a text file is fast. I can get that done for a ~400 page book in less than an hour. It's the proofing that takes me time. Then I want everything to match the original, even quotation marks and apostrophes.