Popular science monthly . to preventthe jack from working loosebecause of jarring the are used toguide drills, reamers, coun-ter-bores, etc. They aregenerally of three types, as shown inFigs. 7 and 8. Bushings must beaccurately located in the jig to insureexact duplication of each part. Thebushing in Fig. 7 fits tightly while inFig. 8 are shown both tight and loosebushings. Clamping is done by means of astandard bolt and nuts, according tothe conditions. In Fig. 9 is shown theapplication of a clamping device. Inmost cases the location points, them-selves, will serve in firmly secu
Popular science monthly . to preventthe jack from working loosebecause of jarring the are used toguide drills, reamers, coun-ter-bores, etc. They aregenerally of three types, as shown inFigs. 7 and 8. Bushings must beaccurately located in the jig to insureexact duplication of each part. Thebushing in Fig. 7 fits tightly while inFig. 8 are shown both tight and loosebushings. Clamping is done by means of astandard bolt and nuts, according tothe conditions. In Fig. 9 is shown theapplication of a clamping device. Inmost cases the location points, them-selves, will serve in firmly securing thework, without additional aid. What was saidwith regard to loca-tion andclampingof jigsholds truewith fix-t u r e s ,though thefix t u r emust bebuilt muchheavier, to make al-lowance for theweight of the cutwhich is usuallyheavier. Bushingsto be used in thedrill jigs are of stan-dard type and canbe found in anystandard machinists handbook. Thefew principles of design touched on hereby no means exhaust the
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1872
