Cylinder Boring and Facing Machine.—Fig. 4 shows a machine built by Pedrick & Ayer, of Philadelphia, for boring cylinders up to 25 in. diameter. The boring-bar is solid forged steel, the screw is of steel with bronze thrust-bearings. The bar can he slipped through the bearing and gearing, or left standing, while the tail-bearing or back pedestal is taken away and the cylinder is placed in position over the bar. The feed-casing is made to feed either way, and has two changes, to operate which it is only necessary to push in or pull out a pin in center of the hand-wheel. The facing-head can be readily placed on the bar as desired, and, if necessary, can be operated at same time the cylinder is being bored. The cutter-heads have a long bearing on the bar, and are arranged for four tools, that number being found by experience the most desirable, as it distributes the stress or strain on the bar. The bed is movable ()11 the shears, and is easily set in position by the hand-wheel at the forward end of the machine.
Dup1P.r Boring-Marhive.—Fig. 5 shows a machine built by Pedrick & Ayer for boring the cylinders of a duplex Siimp at one time. The centers are made a fixed distance apart. to suit the centers of the pnmp-cylinders. The machine is therefore a special one, designed to be used upon hut one size of pump. The platen is fed by a nut and screw driven by a 2+-in. feed-belt ('ylinder Boring-Machines.—Fig. G shows a portable machine built by Pedrick & ycr, of Philadelphia, especially adapted to boring out locmnot ive-cylinders in their places. by removing only 0110 or both heads and piston. The hnek-head. cross-head. or slides need
tint be removed, unless so desired. On removing the piston and leaving the front head and st utling-box, a small cone takes the place of stufling-box, and with proper adjustment at the front head the machine is ready for work: it is fed with a enlist ant (mid eut-gears. The clamps or eross-heads our so arranged that. they may he used conveniently 011 lovoinotive-eylin ders of 1111 sizes, The same bolts or studs that fasten the cylinder-head on arc used to bolt the bar supports also. Two rods are fastened to the ends of the cross-head that supports the bar in the cylinder and to an adjustable swivel cross-head on the end of the screw ; these take the whole of the thrust and tor sion strain of the bar. It makes no difference which position the bar is in, the end thrust is always in line with it, causing it to cut steady, smooth, and true. The feed can be thrown out of gear at any time, and the machine will also feed automatically. An other portable boring-machine, built by Pedrick & Ayer, is de signed for reboring, in present positions, all makes and sizes of steam-engine cylinders. It is so constructed that the piece being bored serves as the bed or sup port of the bar. The cutter heads are fed by a screw in one side of the bar, and are operated by the feed-casing on the end that contains the gearing, by changing position of which two changes can be made, slow feed for roughing out, and fast for finishing cuts. The feed is au tomatic and constant, or at the pleasure of the operator. Thy bar is driven by a train of cut gears either with it crank or belt for power