This section is from the book "Machines And Tools Employed In The Working Of Sheet Metals", by R. B. Hodgson. Also available from Amazon: Machines and tools employed in the working of sheet metals.
Faint straw............................ | Scrapers for brass. |
Steel-engraving tools. | |
Light-turning tools. | |
Hammer faces. | |
Planing tools for steel. | |
Planing tools for iron. | |
Paper-cutting knives. | |
Wood-engraving tools. | |
Flat drills. | |
Milling cutters. | |
Wire-drawing plates. | |
Boring cutters. | |
Brownish yellow...................... | Screw-cutting dies. |
Leather-cutting dies. | |
Taps. | |
Chasers. | |
Hock drills. | |
Punches and dies. | |
Reamers. | |
Shear blades for metal. | |
Gauges. | |
Stone-cutting tools. | |
Plane irons. | |
Twist drills. | |
Wood borers. | |
Light purple............................... | Cold chisels for steel. |
Axes and adzes. | |
Cold chisels for cast iron. | |
Firmer or mortising chisels. | |
Cold chisels for wrought iron. | |
Circular saws for metal. | |
Dark Blue.................................... | Screwdrivers. |
Springs. |
squeezings, the weight when finished being 22 1/2 lb. The number of operations, commencing by cutting out the blank and finishing by lacquering, is 32, including eight annealings and cleanings. As showing the necessity for properly annealing the metal, cartridge cases which have been manufactured by firms of high repute have cracked through their base spontaneously whilst they have been in the stores. This is supposed to be the result of the effort of the material to recover its normal state, and thus to have caused rupture.*
The cause of these troubles has generally been traced to an insufficient number of operations in drawing and annealing during the process of manufacture. It is probable that these troubles would not have happened had the cartridge cases been produced by a greater number of stages, thereby bringing about the flow of the metal in a more gradual manner. In works where the ordinary commercial brass alloys are mixed and worked, and where the metal has to undergo severe torturing in the processes of rolling, drawing, and hammering, and where the general arrangements and number of annealing muffles are insufficient to deal properly with the amount of work done, the metal strip would be kept in the annealing muffle considerably longer, but at a much lower temperature than would be the case in ordinary annealing, thereby giving the metal what is known as a good soaking. The foregoing remarks, although directly concerning the manufacture of metal ammunition cases, teach a lesson with reference to sheet metal work generally, since it is certain that many of the troubles of cracking and splitting during the process of manufacturing sheet metal articles is due to the metal not having been properly annealed between the various stages of progress, and is further frequently caused by endeavouring to produce a difficult article with a stage or process less than should be given.
 
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