Riddles
There is no tool that a moulder uses more constantly than a riddle, and it behooves the proprietor to buy the very best riddle that he can find. The reason is obvious. A cheap riddle is put together in the quickest manner possible, the wood used in the rim is of the commonest kind, and much too light for the purpose. The wire is bought by the pound, therefore the lighter wire is put in the riddle to lessen the cost; the wire for, say, a No. 6 extra-heavy riddle is used for a No. 4 cheap riddle, etc.; then the cloth is cut so sparingly that it does not wrap upon the rim far enough to hold for any length of time. Nine times out of ten one or the other (cloth or rim) gives way before the light wire wears out.
The brass riddle is undoubtedly the best for use on the foundry-floor: it never rusts; the wires are always clean of sand, allowing the use of the full mesh. A steel-wire riddle will rust; and the galvanized riddle having wires of a rough surface, the sand will cling to them, filling up the meshes, thereby taking longer time to riddle the sand.
For iron, coal, or cinder riddles the heavy crimped iron-wire riddle is the best. Those made especially for sifting iron out of sand and other similar uses should be made one-inch mesh, from good strong iron wire. Parting-sand riddles or sieves, any diameter, with or without crossbars, can be obtained from the dealers, and special sizes of heavy steel sand-screens may be had from the same parties, as well as an endless variety of power and portable sand-sifting machines. The revolving riddle or screen is a remarkable improvement on existing methods for sifting and mixing sand. See SAND-SCREEN.