. Railway mechanical engineer . s. The bolt is gripped at thesquare end in a special collet with adjustaijle stop, the turn-ing feed is then engaged from a friction in the apron andtwo turning heads on the slide are fed over the portion ofthe bolt to be finished. Modern die heads with solid cutters for turning andchasers for threadinsr are used. Both the cutters and heads readily operate as a hollow mill, the front head Ijeingequipped with a taper attachment and tapered cutter, givingits cutters a slight opening movement as it feeds cutters in the rear head are straight. Both heads
. Railway mechanical engineer . s. The bolt is gripped at thesquare end in a special collet with adjustaijle stop, the turn-ing feed is then engaged from a friction in the apron andtwo turning heads on the slide are fed over the portion ofthe bolt to be finished. Modern die heads with solid cutters for turning andchasers for threadinsr are used. Both the cutters and heads readily operate as a hollow mill, the front head Ijeingequipped with a taper attachment and tapered cutter, givingits cutters a slight opening movement as it feeds cutters in the rear head are straight. Both heads areopened automatically at the correct instant and are closed byadjustable cams on a slotted Ixir. For threading the cut-ters in both heads are replaced by chasers, those in the fronthead being tapered, ground after hardening and accurate towithin .002 in. The heads are held in a constant relation on the slidewhich is fed forw^ard b) a nut and lead screw in the result is a bolt with threads on both taper and straight. Fig. 4—Threading One End of a Rigid Side Stay ends concentric and in continuous lead and uniform rear die carrier is adjustable on the slide by means of afine pitch screw and may be set for any Ijolt from 14 to 36in. long. A V-block on the slide prevents the bolt fromdragging in the chasers when the die heads are open. Apermanent spacer bar, accurately made, is furnished witheach machine to set the die heads in continuous lead whenchanging for length. For button head radial staybolts across slide is provided for facing the button heads. The machine has a capacity to turn and thread bolts44 in. to 1 J/j in. diameter by 14 in. to .-Sb in. long. Thelength of the slide is 34 in., the maximum turning lengthl;eing 5 in. The approximate floor space is 2 ft. 8 in. by 8ft., the approximate net weight being 3,500 lb. Both ma-chines can lie furnished in geared head type arranged forsingle pulley or motor drive. Apparatus for Taking Microphotographs RAI
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
