. The half-tone process. A practical manual of photo-engraving in half-tone on zinc, copper, and brass. er labour-saving machine is a trimmer (fig. 104).It may be simply described as a rotary shoot plane, itsobject being to trim the ends of the wood mounts quitesmooth and square, after they have been roughly sawnoff. The block is placed on a sliding table, and pushedpast the cutter head, which is provided with two ormore cutters, and revolves at a speed of about 4,000per minute. In using this machine there is a tendency,unless the knives are well set, to jag the under edge of the wood. Thiscan
. The half-tone process. A practical manual of photo-engraving in half-tone on zinc, copper, and brass. er labour-saving machine is a trimmer (fig. 104).It may be simply described as a rotary shoot plane, itsobject being to trim the ends of the wood mounts quitesmooth and square, after they have been roughly sawnoff. The block is placed on a sliding table, and pushedpast the cutter head, which is provided with two ormore cutters, and revolves at a speed of about 4,000per minute. In using this machine there is a tendency,unless the knives are well set, to jag the under edge of the wood. Thiscan be avoided by placing under theblock a thin sheet oflead, and taking a cutoff that at the sametime. Although mountingwood can be boughtready planed to gauge,it is found an economyin large establishmentsto have a planingmachine (fig. 105),and prepare the wood on the premises. The planingmachine is in the form of a horizontal disc, with twocutters set in its underside, and the wood is clampedto a travelling bed, which automatically passes underthe cutter disc. The usual practice is to plane up short. Fig. 105. THE MOUNTING AND PROOFING. 1/3 lengths from i8in. to 2ft., somewhat above the properheight. The mounter pins his plate on to a corner ofone of these lengths, saws off the piece close to theplate, and puts the blocks on the bed of the planerwith the cut face downwards. The cutters are set bymeans of an adjusting screw to plane exactly typeheight, and the block is therefore sure to be accurate andparallel. The sides are next squared up on the trimmer. The foregoing comprise all the machines that can beusefully employed by the photo-engraver. Sometimesa power-drilling machine is used in large establish-ments, and the circular saw is often duplicated so as tokeep one machine for metal and the other for different types of routers or bevellers may be usedwhere there is a large volume of work, but in generalone or two good mounters can keep pace with half-a-dozen or more
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Keywords: ., bookcentury1900, bookdecade1900, bookidhalftoneproc, bookyear1904
