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.
Having had occasion to use several snap hooks of various sizes and being unable to find anything suitable for my purpose on the market, I pro-cured several cotters of the desired sizes and by bending them over, as shown at A. and cutting them off, as at B, I had snap hooks which, besides answering my original purpose, have also found use as key rings and tool-chuck holders. - Contributed by Jos. J. Kolar, Maywood, Ill.