United States or Trinidad and Tobago ? Vote for the TOP Country of the Week !
The dowel-pins steer the key into the key-way across the end of the shaft, and the key compels the block to turn with the shaft. There is also a threaded hole in the under side of the top block. This is for the introduction of a screw which is used to pull the top block off the end of the shaft. If taken off at all it must be pulled, for the dowel-pins, key and counterbore are close fits.
The large block which with its threaded bronze bushing forms the nut for the screw is called the cover-plate, and is held to the base of the machine by eight 1-1/2-inch cap-screws. On the upper side are two dowel-pins which enter the lower step and keep it from turning.
The walls of the fort were twelve feet high, thus requiring nine courses of these timbers laid edgewise one above another, each being doweled to the one below by red oak dowel-pins, two of which were pulled out of their quiet resting places of 141 years' duration, in a good state of preservation, by Mr. Maxwell and the writer, Sept. 5, 1885.
The step-lubricant is forced up through this hole and out between the raised edges in a film, floating the rotating parts of the machine on a frictionless disk of oil or water. The upper step-block has two dowel-pins, also a key which fits into a slot across the bottom end of the shaft. The upper side of the top block is counterbored to fit the end of the shaft. The counterbore centers the block.
Word Of The Day