Unique Grinding Operations
From "The Abrasive Handbook", 1928
The Penton Publishing Cy CLEVELAND OHIO
Does the modern abrasive engineer realize that large wheels are used for grinding truffles? This statement may be taken for a joke, but it is authentic. Truffles are toothsome roots that are regarded as rare delicacies. They form an ingredient of certain delectable sauce concocted by the French chef and sometimes they are served with steaks and the dressings of roast fowls. They grow profusely in the region de Perigord in Southern France. They are underground roots of tbe mushroom family. Pigs are extremely partial to truffles, so the truffles gatherer enlists the porker's aid in a practical manner. The pig locates the truffles and digs it out. Then the truffle hunter raps the pig on the snout and takes the truffle away before it is eaten.
After the dirt is removed from the truffle it must be pared as it has a tough shell about 1/4-inch thick. It grieves the soul of the thrifty Frenchman to lose any of the edible weight of the truffle, so someone devised the plan of grinding away the thick skin. Thus the truffle grinding wheel became a commercial possibility. Records at the plant of the Carborundum Co. reveal that hundreds of wheels 30 inches in diameter, 4-inch face, 24 grit, H grade have been supplied for this purpose.
Grinding wheels also are used to a great extent in the feather industry for removing the fuzz of featherlets that grow along the quills of such feathers as ostrich plumes. Formerly the quills were clipped, but this process was slow and unsatisfactory so that grinding wheels were substituted successfully. Today grinding wheels are an important factor in the feather factory as their labor saving possibilities are realized.
For many years small grinding wheels have been used by dentists for grinding porcelain, that substance which forms the outer covering of teeth, but few users of abrasives are aware that grinding wheels are used regularly by veterinary surgeons for repairing the teeth of horses. Formerly a file was employed for this purpose, the grinding plan originating in the British army about 15 years ago. The horse, being a highly nervous animal, objects to having his teeth filed, and now the operation is performed more rapidly and with less trouble with a small carborundum wheel mounted on a flexible shaft.
Another peculiar use for grinding wheels consists of finishing celluloïd dolls. These toys are formed in molds, one-half at a time, and two sections are joined together. This leaves a seam that is removed effectively by grinding with carborundum wheels mounted on small bench stands.
Some years ago the Carborundum Co. received a request from Russia for sets of carborundum blocks. Investigation revealed that the blocks were used in a Moscow factory for making plush. The factory superintendent experimented with carborundum slabs 12 inches long, 2 inches wide and 1/4-inch thick, attached to long handles. The slabs were pushed across projecting fibers, the sharp crystals of carborundum raising a plush-like surface.
In the little village of Edar (it would rather be "Idar-Oberstein", the ed.), in Southern Germany, agate, sapphire, turquois and other semiprecious stones have been finished by grinding for many generations. The only change in the grinding method was made when artificial abrasive wheels were substituted for grindstones. The operators still lie on their stomachs while grinding. Huge logs, partly hollowed out and worn smooth through years of use, are placed one in front of each wheel, the operators lying face downward on these logs so that they can grind the work on the bottom of the wheels.
Grinding wheels also find a unique place in the whaling industry. The old practice was to cut the blubber in chunks, put it in huge cauldrons and boil out the oil. In the abrasive extraction process, a coarse carborundum wheel is used. This unit is 24 inches in diameter, 4 to 5-inch face. The chunks of blubber are held against the wheel, at the same time being heated with steam. The wheel cuts and shreds the blubber into a fine pulp which then is passed through a centrifugal separator. It is said that this process results in a high quality product that is odorless and tasteless, which extends its usefulness.