Document 7RLmq2O4E7yrGoa62em9BXzk6

MACHINE TOOLS to stnke the cutter while adjusting or set ting up Splash guards, especially on automatic machines, should be installed and kept in good condition Enclosure guards over the chuck confine hot metal chips and oil splashes, and also act as exhaust hoods for removal of fumes When steel and some other materials are turned on lathes, the chip produced is in a Fig. 24-4. Chip breakers may be ground into the tip of the tool (A) or a breoker in the form of a piece of metal may be clamped or brazed onto the tool Itself (6) Drills The most common causes of injury m drilling operations are 1. Contact with the spmdle or with the tool 2 Breaking a tool 3 Using dull tools 4 Being struck by insecurely clamped work 5 Catching hair or clothing m the revolv ing parts 6 Sweeping chips off by hand 7 Leaving key or drift in chuck To guard a spindle, a simple sleeve guard or other bamer that protects the operator from contact with the spmdle can be used (Fig 24-5) The tool itself can be guarded by a tele scoping guard that covers the end of the tool, leaving only enough of it exposed to allow easy placement into the piece being worked. A spring safety guard can be attached to a small dnll press and as the head descends, the spring compresses so that it can contain continuous spiral which frequently causes hand and arm injuries To eliminate this exposure, one of two types of chip breaker should be used (Fig 24-4) Boring Machines Bonng consists of cutting a round hole by means of drills, bonng cutters, or ream ers The drdl press, in its vanous forms, is probably the best known machine tool be cause of its frequent use in home work shops Drilling machines are equipped with rotating spindles, handles, and chucks carry ing pointed or fluted'cutting tools Opera tions performed with drilling machines in clude countersinking, reaming, tappmg, fac ing, spot facing, and routing Bonng mills use a cutter, either smgleor double-edge, mounted on a supporting shaft to true up or enlarge a hole that has already been roughed out by a drill or formed m a rough casting or forging Fig 24-5. Guards that afford protection against chips and broken drills and yet preserve visibility The filler on these guards is wire mesh. 24-5