Popular science monthly . At the left is shown the usual way of hoisting logs. At the right may be seen a new arrangement which saves power SEVERAL thousand cedar poles can beremoved from a river and depositedon flat cars alongside by means of anordinary stiff-leg derrick with a hingedboom. Instead of setting the mastvertical, the top should be inclinedabout i8 ins. toward the river, its heightbeing about 50 ft. Instead of attaching the snatch-blockfor the hoisting cable to the foot of themast, anchor it about 18 ins. from thefoot of the mast, on the land side. Inthis way the boom is swung aro
Popular science monthly . At the left is shown the usual way of hoisting logs. At the right may be seen a new arrangement which saves power SEVERAL thousand cedar poles can beremoved from a river and depositedon flat cars alongside by means of anordinary stiff-leg derrick with a hingedboom. Instead of setting the mastvertical, the top should be inclinedabout i8 ins. toward the river, its heightbeing about 50 ft. Instead of attaching the snatch-blockfor the hoisting cable to the foot of themast, anchor it about 18 ins. from thefoot of the mast, on the land side. Inthis way the boom is swung around bythe cable when the load is lifted, andwhen the load is dropped the leaningmast causes the empty boom to returnover the water, thus making it automaticeach way through 180 degrees. By theobservance of such a simple expedient astilting the mast, a great deal of labor issaved.—J. L. With this newly arranged derrick largequantities of logs can be raised from a riverand deposited on flat cars in a short time An Adjustable Tap Wrench ONE oftap V A serviceable wrench the bestip wrenchesto be had can bemade in a few min-utes by anyone following these directions:Cut a piece of J g-nch sq. tool steel 10ins. long, exactly in the middle, lea^•ingtwo 5-inch pieces. Lay these piecesover each other a distance of iJ/2 ins.;clamp the lapped ends in a vise and ^^in. from each end of the lap, drill a hole through the lap. In one piecetap the holes with a 14-24 tap, and re-drill the holes in the other piece with a ^-inch drill. LIse two 14-24 cap screws I m. long, and file the threads off adistance of ?^ in. from the head. Put\Our two pieces together and mark offthe exact center of the lap, then file aY-shaped slot 3-32 in. deep in eachpiece, to hold the tap. Round off the handles with a file andemery cloth and, if desired, the wrenchmay be hardened to a blue steel finish.
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1872
