. Railway master mechanic [microform] . d with a screen of a different tex-ture. Bolting silk of every size of mesh used in a flour mill isused in the various bolting machines, and the ground materialis* sifted through into hoppers, the contents of each beingnicely exact in the size of the grains to which the material hasbeen reduced. The product, ready for the sandpaper, varies indegree of fineness from the coarse article that is used on theheaviest sandpaper to an impalpable dust that leaves no sugges-tion of grit when rubbed between the fingers, but which retainsthe cutting qualities intact
. Railway master mechanic [microform] . d with a screen of a different tex-ture. Bolting silk of every size of mesh used in a flour mill isused in the various bolting machines, and the ground materialis* sifted through into hoppers, the contents of each beingnicely exact in the size of the grains to which the material hasbeen reduced. The product, ready for the sandpaper, varies indegree of fineness from the coarse article that is used on theheaviest sandpaper to an impalpable dust that leaves no sugges-tion of grit when rubbed between the fingers, but which retainsthe cutting qualities intact. The bolted material is stored inbins until required in the next process. The glue comes in big barrels, and is so important a factorin the making of sandpaper that there have been 1,800 barrelsused annually for this purpose. The dry glue is fed through ahopper in the floor into a boiler in which it is cooked, and thehot material is again conducted, on the floor below, to themachines, the abrasive being fed to the proper machines from. High Speed Sensitive Drill, With Two-Foot Arm. October. 1909. RAILWAY MASTER MECHANIC 415 the same floor. The fourth floor, where the sandpaper is actu-ally made, looks at first glance like the drying room of a laundry,folds of paper being suspended from racks that move automat-ically, the paper being carried in a waving line through hundredsof yards of space, weaving its way back and forth on the dryingracks. The machinery with which the paper, glue and mineral arebrought together is intricate, but looks simple enough. Thelight brown paper of various weights comes in rolls up to 48inches wide. This is run into a machine, the first function ofwhich is that of a printing press. As the paper is printed, it is carried on through another setof rolls and receives its coating of glue. Turning over, above,to another machine, it passes through controlling rollers and re-ceives its deposit of mineral of the size proper to the textureof the paper, then is
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1895
