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Machinist dies after being struck by object thrown from turning lathe.
Minnesota Department of Health
Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, FACE 97MN028, 1998 Jan; :1-5
A 42-year-old male lathe operator (the victim) died after being struck by a metal object that was thrown from a lathe. The victim was setting up the lathe for a production run of parts. He bolted an unfinished part to a holding device known as a fixture and mounted the fixture in the hydraulic jaws of the lathe's chuck. Although the required hydraulic jaw pressure for machining the production run was 300 pounds per square inch (psi), the manually controlled jaw pressure was not changed from the previous parts run for which it had been set at 170 psi. After installing the fixture in the jaws of the chuck, the victim closed an access door on the front of the lathe. He turned the lathe on and it began to machine the part by finishing a groove in its outer edge. During this portion of the process, the fixture and the part were spinning at approximately 500 revolutions per minute (rpm). After the outer edge was finished, the computer controlled lathe automatically increased the speed of the chuck to approximately 1500 rpm. When the speed increased, the jaws of the chuck could not securely hold the fixture and the part because the jaw pressure was still set at 170 psi. The victim heard several banging sounds coming from the lathe and attempted to reach an emergency stop switch located on the lathe. The victim was struck in the head by the fixture and the part after they knocked the access door off the lathe and were thrown across the workshop. Other workers in the area rushed to aid the victim and placed a call to emergency medical personnel. Emergency personnel arrived shortly after being notified and transported the victim to a local hospital. Later he was transferred to a major medical center where he died two days later. MN FACE investigators concluded that to reduce the likelihood of similar occurrences, the following guidelines should be followed: include operator prompts on the lathe control panel screen to ensure all system parameters are properly set; 1. develop secondary couplers to retain items being machined if the lathe's jaws fail to secure items; 2. develop a mandatory checklist for each set-up procedure to ensure that all steps are properly completed before machines are started; 3. and place warning signs on machines to remind operators to properly set all manually controlled settings before starting machines.
Region-5; Accident-analysis; Accident-prevention; Accidents; Injuries; Injury-prevention; Traumatic-injuries; Work-operations; Work-analysis; Work-areas; Work-performance; Work-practices; Safety-education; Safety-equipment; Safety-measures; Safety-monitoring; Protective-measures; Protective-equipment; Machine-guarding; Machine-operation; Machine-operators; Machine-shop-workers; Warning-signs
Field Studies; Fatality Assessment and Control Evaluation
NTIS Accession No.
National Institute for Occupational Safety and Health
Minnesota Department of Health
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division