Smithy MIDAS MI-1220 LTD, Руководство оператора, Страница: 45 / 133

Figure 10.14 Steady rests mount on the lathe bed and provide three bearing surfaces
Follow Rests
Long or slender shafts that are apt to spring out of have a slight ground taper and
alignment by the thrust of the cutting tool often require a follow rest expanding collar.
Follow rests mount on the carriage of the lathe and move with the tool, backing up the
workpiece opposite the point of the tool thrust. They have two adjustable supporting
jaws, one holding the work to keep it from climbing up on the tool and the other behind
the work to counter the thrust of the tool.
Note:
Take great care in adjusting the jaws of rests, as they must form a true axial
bearing for the work and let it turn freely but without play.
Figure 10.15 Follow rests mount on the lathe carriage and move with the tool.
Setting Up Work in a Chuck
Chucks usually hold work that is too short to hold conveniently between centers or work
requiring machining at, into (boring or inside threading), or across its end. While it is
possible to set up such work on a faceplate, the convenience of chucks has made them
part of every complete lathe. Lathe chucks come in many types and sizes and hold
workpieces of diameters approaching the swing of the lathe.
For ordinary use, there are two standard types of headstock chucks. The four-jaw
independent lathe chuck has four holding jaws that can operate independently and adjust
to hold round, square, eccentric, or odd-shaped work (Figure 10.16). The three-jaw
universal geared scroll chuck holds only round or near-round work with three, six, nine,
12, or other multiple-numbered sides. It always holds work concentrically. The three-jaw
chuck has the advantage of being self-centering-all jaws move in or out together (Figure
10.17).
Midas 1220 LTD Operator’s Manual
10-7
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