Hmm.. After measuring the thickness of one manual and counting the pages, I estimate that the complete set is about 3500 pages.
How much time will it take a person to scan a page, fiddle with it in software and print it to a PDF file? I'd guess 2 minutes is very optimistic, probably more like 3 minutes. Let's use 2.5 minutes as an example. Maybe someone with some programming skills could write a macro or script to automate the process.
3500 x 2.5 minutes is 8750 minutes, or 146 hours. At 8 hrs/day, that's over 18 days as a 'fulltime' job.
I'd guess running them off on a copier might take 15 seconds per page to print one copy, more copies could be run later from the 1st copy, on an automatic copier to save time. 3500 x 15 sec = almost 15 hours standing at the copier.
BTW, I could not find any copyright notices in any of the manuals, so one could argue that copying them violates no copyright laws.