Workshop appliances including descriptions of the gauging and measuring instruments, the hand cutting-tools, lathes, drilling, planing, and other machine-tools used by engineers

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 Excerpt: ...of wrought-iron; the mandril of steel, and its bearings of gun-metal. The only parts of it which are of wood are the backboard (m), and the front of the treadle (e). The conical form of the flywheel and pulley enable their relative speeds to be varied; so that this lathe can be used either for wood or brass, either of which require considerable speed and but little power; or for iron or steel, for which these conditions must be reversed. In the case of soft materials, the size of the work is limited as to length by that of the available part of the lathe-bed, and as to diameter by the height of the centre of the mandril above it. As the diameter of the work cannot be more than twice this height, it is necessary to know it, and also the length of the bed, in order to judge of the capabilities of a lathe. That in the figure would be described as a ' 5-inch lathe, 3 feet 6 inches bed.' For the use of amateurs, lathes are made in considerable variety. It is generally required of them that they shall be light in appearance, well adapted for either soft or hard wood, and also for light work in metal. For the first of these purposes it is essential that a lathe should run freely at a high speed, a condition not often fulfilled by those of the class shown in the preceding figure. Considerable gain in this respect results from the abandonment of the parallel bearings of the mandril there depicted, in favour of that shown in the section of the Fast Headstock, which occupies the left-hand portion of Fig. 99. At its hinder end this mandril has a steel centre-point, which is supported in the slightly hollowed extremity of a screw, also tipped with steel. A fine leading-hole drilled truly in the centre runs for Headstocks of Foot-Lathe. 145 some little distance into the ...