Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . g to the ra|iid rateat which it is driven. The danger of frai-ture can-not be entiridy obviated, but may be much clauiiiing the stone on its a.\is by disks wedges between the sides of the eye andthe s(iuar(? arbor on which it it suspended. Itwould seem possible to avoid the eye altogether, anddepend upon cheek-pieces with studs o
Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . g to the ra|iid rateat which it is driven. The danger of frai-ture can-not be entiridy obviated, but may be much clauiiiing the stone on its a.\is by disks wedges between the sides of the eye andthe s(iuar(? arbor on which it it suspended. Itwould seem possible to avoid the eye altogether, anddepend upon cheek-pieces with studs or projectionswhich penetrate into depressions in the sides of thestorje. The stones are so very heavy that theirfracture when in rapid motion is apt to do greatdamage to life, limlj, and |iroperty. ArtiKcial stones are largcdy employed, especiallyin dry-grinding and polishing. The corundum stone used by the Hindoos andChinese is composed of corundum powdered, 2parts ; lac-rcsin, 1 part. The two an^ intimatelymixed in an earthen vessel, kneaded, flattened,shaped, and polished. A hole for the axis is madeby a heated copper rod. The grain is more or less fine, according to thegrade of the powdered corundum. The wheel is Fig. Grindstone and Hangings. monnted horizontally, ami revolved by a bow in the right hand of the workman, while the left applies the work to the stone. The following recipe may also be employed : —Sand of the recpiired (ineness, .3 or 4 ; shellac, 1 part; melted, incorporated, and molded under pressure. Ransomes artificial stone, sand agglomerated by silicate of lime, has been used for grindstones withexcellent ettect. In a test tiial between Ransomes (English) arti-ficial grindstones and some Newcastle grit to which had the greatest abrasive eflect, it wasfound that the Ransonie stone ground away \ ouncefrom a steel bar J inch diameter in sixteen minutes,while a Newcastle stone (natural giit) driven attwenty per cent greater speed req
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