following precautions can reduce the chance of injury:  Lathes are used in turning work of a cylindrical nature.  This work may be performed on the inside or outside of the  cylinder. The work is secured in the chuck to provide the  rotary motion, and the forming is done by contact with a  securely mounted tool. The following precautions can reduce  the chance of injury:  Milling machines are used to shape or dress; cut gear  teeth, slots, or key ways; and similar work. The following  precautions can reduce the chance of injury:  Grinders are used to sharpen tools, dress metal, and perform  other operations involving the removal of small amounts  of metal. The following precautions can reduce the chance  of injury:  The flight line is a place of dangerous activity. Technicians  who perform maintenance on the flight line must constantly  be aware of what is going on around them. The noise on a  flight line comes from many places. Aircraft are only one  Welding on an aircraft should be performed outside, if  possible. If welding in the hangar is necessary, observe  these precautions:  Welding must be performed only in designated areas. Any  part that is to be welded must be removed from the aircraft, if  possible. Repair would then be accomplished in a controlled  environment, such as a welding shop. A welding shop must  be equipped with proper tables, ventilation, tool storage, and  fire prevention and extinguishing equipment.  •  Wear eye protection.  •  Securely clamp all work.  •  Set the proper revolutions per minute (RPM) for the  material used.  •  Do not allow the spindle to feed beyond its limit of  travel while drilling.  •  Stop the machine before adjusting work or attempting  to remove jammed work.  •  Clean the area when finished.  •  Wear eye protection.  •  Use sharp cutting tools.  •  Allow the chuck to stop on its own. Do not attempt to  stop the chuck by hand pressure.  •  Examine tools and work for cracks or defects before  starting the work.  •  Do not set tools on the lathe. Tools may be caught by  the work and thrown.  •  Before measuring the work, allow it to stop in the lathe.  •  Wear eye protection.  •  Clean the work bed prior to work.  •  Secure the work to the bed to prevent movement  during milling.  •  Select the proper tools for the job.  •  Do not change the feed speed while working.  •  Lower the table before moving under or away from  the work.  •  Ensure all clamps and bolts are passable under  the arbor.  •  The aircraft being welded must be in a towable  condition, with a tug attached, and the aircraft parking  brakes released. A qualified operator must be on the  tug and mechanics available to assist in the towing  operation should it become necessary to tow the  aircraft. If the aircraft is in the hangar, the hangar  doors are to be open.  •  Trained fire watches are to be present in the area  around the welding operation.  •  Fire extinguishing equipment of a minimum rating  of 20B must be in the immediate area with 80B rated  equipment as a backup.  •  The welding area is to be roped off and placarded.  •  Only qualified welders are permitted to do the work.  •  No flammable material is permitted in the area around  the welding operation.  •  No aircraft are to be within 35 feet of the welding  operation.  •  Painting is not permitted.  •  During welding operations, open fuel tanks and work  on fuel systems are not permitted.  •  Do not stand in the arc of the grinding wheel while  operating in case the wheel explodes.  •  Check the wheel flanges and compression washer.  They should be one-third the diameter of the wheel.  •  Do not force grinding wheels onto the spindle. They fit  snugly but do not require force to install them. Placing  side pressure on a wheel could cause it to explode.  •  Inspect the grinding wheel for defects prior to use.  •  Wear eye protection, even if the grinder has a shield.  Flight Line Safety  Hearing Protection  1-4 