Lost art of folding a newspaper. You have permission to edit this article.

By folding and cutting letters in various clever patterns, people attempted to hide their correspondence from unwanted readers, and the "locks" came in myriad types. "This isn't something special ...

Much as its names suggests, letter-folding equipment folds sheets of paper. Sheets of paper are fed either manually or automatically through the machine. While some models stop there, others will ...