The Locomotive Of Today

128 The Framing, Wheels, etc. : Axleboxes. project clown through the hornstay for carrying the coiled springs. In some cases two smaller pins on either side parallel with the large one also pass through to secure the keep. The keep acts as a reservoir for the lubricant retained in it, the latter being kept up to the under side of the bearing by means of pieces of sponge or horsehair preparations, worsted pads with springs being also used for this purpose. The top of the box is cored out, both to lighten it and to form an oil receiver for supplying the journal. Holes are drilled through to a long channel, cut deep and broad along the top of the crown, so that the oil may be well distributed along the entire length of the bearing. Worsted syphons lift the oil out of the recesses at the top of the box and supply the channel. Strips of white metal are also let into the face of the bearing on each side of the centre line of the crown, both to reduce friction and act as a safeguard if the bearing should heat, as the softer metal melts and forms a lubricant itself which often saves the bearing from being cut. The white metal is run in and turned with the gunmetal. When the boxes have been fitted to the guides all the centres are correctly set out, and the boxes are bored out and then fitted to the journals by chipping, filing and scraping. There is a difference of opinion as to how far the bearing should lit the journal, but it should not be allowed to touch quite down to the centre line, or there will be a tendency to bind here, and heated bearings will be the result. The oil recess along the crown and white metal strips have been found to prevent slackness and knock to a great extent, as they allow of most wear taking place in the crown. A thin cover plate of metal, with a strip of leather below it, is put on top, and prevents access of dirt, etc. The amount of side play allowed both in guides and bearing is very small; in faet, in most cases, with coupled wheels especially, there is none recognised, the working fit providing quite sufficient for all practical purposes. A box suitable for outside bearings and overhung springs is illustrated at D. The box is of cast iron, and is fitted with brasses which have the usual white metal strips along each side of the crown, but as the pressure is direetly applied to the top of the box by the spring pin, the centre of the crown has not got the wide oil groove provided in the previously mentioned example. The keep below is also of cast iron, and held in place by two pins passed through. Phese are prevented from coming out when the box is in position by the faet of the box sliding in the guides.