IRON PLANING, AND CUTTING ENGINE ROOMS.
Returning hence to the leading and principal feature of these works, the manufacture, namely, of all the various instruments and appliances for the art imprimatorial, we are next ushered into the iron planing and cutting engine rooms, for the cutting the cogs of engine wheels, and finishing the surfaces of whatever portions of the machinery must be brought to a smooth and polished face. This is done by the propulsion of the pieces of metal so to be planed, in a horizontal and longitudinal direction against cutting edges, which again move horizontally across the moving planes, and are pressed downward on them vertically, so as to bring the planing to the requisite depth. The abraded portions are thrown off from the surface, of cast iron in a sort of scaly dust, from wrought iron in long, curled shavings, and the planes can be wrought up to almost any desirable degree of finish and smoothness.
The cutting engine for the formation of cogged wheels, bears some relation to that for the teething of saws, the cutter impinging downward, with an action in some degree intermediate between that of sawing and filing, upon the exterior circumference of the circular wheels, which revolve on their axis under them in a rotation so regulated to the fall of the striker as to insure absolute equality in the width of the cogs or projections.
[Conclusion in our next
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