Document wKVynGQo3R7davDOaDg8Jydp3

31--Machine Tools pletely enclosed with a sliding fixture at tached to the slide, except for the point at which the cut is made. The length of blade exposed should be not more than the thickness of the stock being cut plus X in Flying particles of metal can be confined by a metal or transparent plastic guard installed in front of the saw. On a hand-fed operation, care should be taken at the end of a cut Use a push block, not hands. Spinning lathes A spinning lathe is a forming tool rather than a machine tool and usually requires a specially skilled and qualified operator Unsafe practices which should be prohib ited in operation of a spinning lathe mclude. 1 Inserting blanks and removing the pro cessed part without first stopping the ma chine 2 Failing to tighten the handle of the tailstock sufficiently, so that the blank may work loose or ruin the stock or tool 3 In trimming copper and certain grades of steel, allowing the swarf to build up into a long coil This last practice has caused hands to be severed and arms severely cut One fatality has been reported from a coil which became snarled around the operator's neck Opera tors should remove the tool, when necessary to allow the swarf to break off The chuck of a spinning lathe is usually a form built up of hardwood, shaped exactly like the finished part If the piece being worked must be "necked-down," so that after the piece is formed the chuck cannot be taken out, the chuck is made m sections held to gether by locking rings or locking grooves There is a great hazard from the chuck's flying apart if the grooves should become worn or the rings should break In view of the speed of spinning lathes (500 to 2000 rpm), the danger of flying sections of the chuck is obvious Prevention of injuries from this cause lies m penodic inspection and main tenance of chucks Similarly, lathe tools should be inspected frequently for cracks in the handles or in the tools themselves 838 Courtesy Intemattonal Harvester Company On some older equipment, vibration or worn parts may cause the tailstock to loosen during operation and the piece to work loose or fly off, exposing the operator to almost cer tain injury Again, the solution is frequent inspection and maintenance Gear cutters In the operation of gear cutters and hobbers (Fig 31--11), both the tool and the work move during the operation As a result, the point of operation guard should be simple and easily adjusted On operations where the work (gear blank or rough-cut gear) is moved to the tool, a simple barner guard, formed to cover the point of operation and sized to fit the work, is satisfactory The guard can be mounted on a spindle that carries the work so that the guard will fit over the point of operation, when the work is brought into position When the tool is brought to the woik and when the tool and work are adjustable, an encircling type of guard may be attached to the tool head Such a guard can be an auto matic dropgate device, which can be equipped