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The Babbitted Bearings
First, drill three holes radially near each end of the tee and wye (see Fig. 80) for No. 6-32 screws which will be used to center and support the shafting in the fittings
while the babbitt is poured. The ends of these screws should be smoothed with a file so that they will not mar the surface of the shafting. Holes for the 3/8" clamping screws (L, Fig. 72) should be drilled and tapped into the tee and wye, and the screws, coated with lampblack and oil, inserted prior to babbitting and brought
up just to contact the shaft. The ends of these screws should first be filed quite flat. Two or three V cuts should also have been made across the internal threads of each of the fittings, the purpose being to provide grooves that will act as anchorage for the babbitt bearing.
Make up the polar axis tight in tee E. It will have to be removed later, so in order that it may again be returned to the same exact position, drill a hole through the branch opening of the tee into the shafting. In the final assembly, a pin or screw should be inserted in this hole. Slip the collar into place, snug against the tee. Now smear the polar axis and the collar with a mixture of thin lubricating oil and lampblack, to prevent the babbitt sticking to the metal.
Place the polar axis in the wye fitting, with its collar bearing against the upper face of the wye, and carefully center it with the set screws. To prevent the molten babbitt from running out, fit an asbestos paper or thin sheet-metal collar over the other end and seal up any gaps with putty.
One or two pinhole perforations in the collar will allow the escape of air. Brace the assemblage so that it cannot roll during the pouring operation (see Fig. 81). A poor bearing is apt to result if the babbitt is poured into cold metal, so while the babbitt is melting a torch should be used to preheat both casting and shaft. In heating the shaft, apply the flame to its protruding ends, else the oil film may be burned away, and there is then danger of the babbitt sticking to the metal. It is not necessary to bring the parts up to the temperature of the molten babbitt, which melts at from 500° to 600° F.; about 200° to 250° will suffice.
babbitted bearings part2
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