This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Envelopes make a very inexpensive as well as a neat file for papers and letters if they are arranged and fastened together so that they can be kept in one packet. In making such a file procure as many envelopes as there will be headings in the file, also a number of strips of gummed tape, about 1 1/2 in. long. There must be twice as many of these strips as there are envelopes.
Bind the backs of two envelopes, A and B, together leaving a space of 1/8 in. between the envelopes. Bind a third envelope, C, to B, and so on. The strips of tape from A to B and from B to C are on opposite sides of the envelope B. Continue binding unTil the required number of envelopes have been joined together. Assign a heading to each of the envelopes, and the file is ready for use. When completed it should appear as shown in D. - Contributed by Alfred Rice, Syracuse, N. Y.
Ill: The File is Built Up of Envelopes Joined Together with Small Strips of Tape