Exhaust Tumbling-barrels
The Encyclopedia of Founding (1892)
The advantages of this useful adjunct to foundry operations is thus described: Not alone does this machine do away with the horrible clatter and din in the milling-room, but it also keeps the room clear of dust, besides accomplishing an actual saving of twenty-five per cent in time in cleaning the castings. The staves of the machine are made of two-inch well-seasoned oak timber, lined with hard steel plates. Each stave is so bolted that, no matter where the machine stops, the staves can be taken out and replaced without trouble. As soon as the sand is loosened from the castings and is pulverized sufficiently fine for the exhaust to lift it, it is immediately carried away to a box or receptacle which may be placed at any point in or out of the mill-room. This taking away the dust is where the saving of time in cleaning is accomplished. These barrels are substantially made and nicely finished, and have a very attractive appearance. The barrels are operated by belt to the first one, and the rest are run by friction bearings. As many barrels as are needed can be placed side by side and operated by the same belt. Any one barrel can be stopped or started at will by turning a wheel-handle which raises or lowers the barrels from contact with the friction wheel. They are the most complete, easiest-running, most noiseless, cleanest, and most satisfactory tumbling-barrels that can be made. The foundry-supply companies furnish these machines either octagon or square shaped, as well as exhaust-fan for carrying away the dust. See TUMBLING-BARREL.
What Has Changed in the Last Century
When the Encyclopedia of Founding wrote this in 1892, carrying the sand away was sold as a convenience — it stopped the "horrible clatter" and saved a quarter of the cleaning time. The health case was not made: foundry sand is largely silica, and it was the silicosis epidemics of the 1920s and 1930s that turned dust extraction from an attractive option into a legal duty, now written into occupational exposure limits for respirable crystalline silica. The rumbling oak barrel with steel liners was also largely displaced for cleaning castings by centrifugal blast-wheel machines from the 1930s onward, which throw steel shot at the work instead of grinding it against itself. Tumbling survives as mass finishing — deburring and polishing in rotary and vibratory barrels with abrasive media — rather than as the foundry's main way of getting sand off a casting.
Written for this edition, 2026.