Geesh, I remember that my Dad’s offices purchased new heavy office manuals in the late 1960’s and early 1970’s. I also remember thinking I had made the big time when I blew a wad on a portable electric Olivetti for personal use that was the same year the Apple II came out. Before that I used cheap portables and old hand-me-down Underwoods or Royals.
There was a vigorous rebuild trade at the time ~ I bought a rebuilt tank like hunk of iron that was stable enough to do straight lines of type. Built my forearms like nobody's business, but that and factory jobs to pay for college also helped.