The Locomotive Of Today

The Boiler: Palm Stays, Longitudinal Stays. 15 The corners of the internal firebox should be made of large radius, so as to dispense with the necessity for a too close staying there, thus permitting more flexibility than could otherwise be obtained. 1 he portion of the firebox tube plate, immediately below the tubes, is connected to the barrel by palm stays, E., which are flattened at one end to take rivets for attachment to the barrel, and are provided with a boss at the other, drilled and tapped to receive set bolts. These latter may be of copper, screwed in and hammered over, the same as the other stays; or they may be of iron, and have cupheads and squares, the latter being used to screw the stays home, and afterwards cut off with a hånd chisel. In some recent boilers these palm stays have been dispensed with by flanging the throat plate of the firebox to a small radius and having- a row of stav bolts close up to it. As to the ends of the boiler the upper parts of the front tube plate and back plate are the only portions usually stayed. These may be connected together 'by longitudinal stays of round bar iron or steel of about i^-in. diameter passiny through the full length of the boiler from back to front. They are screwed into holes in the back plate, tapped large enougii for the front screwed portion of the stay to clear, and this latter is secured to the front plate by nuts on each side of it. All the joints are made with washers of sheet copper. F shows this foi ni of longitudinal stay, which being- heavy, is supported at the centre to prevent sagging by bearers provided across the barrel for this purpose. Another method of longitudinal staying is by stay bolts that do not run the entire length of the ’boiler, but have feet w hich are rivetted to the barrel plates, or forked ends connected to angle irons attached to the barrel at various points in its length, with either screwed ends for nuts, as clescribed for the long stays, or forked ends which embrace T irons rivetted on to the back and front plates respectively, as at G. A third method is to provide “gusset ’ or plate stays, which are formed of pieces of plate connected to pieces of angle iron rivetted to the barrel, and end plates similar to H in the Fig. Ihe remaining flat surface of the boiler is that portion of the tube plate that receives the tubes below the above-described ongitudinal stays. Here in some examples a few of the tubes are made thicker, screwed in, and fitted with check nuts, whilst ln others longitudinal stays are clistributed among the tubes, t is not usually considered necessary to support these plates, nowevei, as the tubes themselves act as stays, and the area of plate exposed to pressure is inconsiderable.