Abstract: At 8:00 p.m. on May 28, 2021, an employee working as a machinist for a manufacturer of metal fasteners and structures for aerospace was working in the panels department. The employee was operating a CNC F100 running a batch of parts into the machine. During the run, the parts are fed into the chuck jaw automatically. Several of the final products were out of compliance and the employee decided to rework those parts without discussing it with the coworker who serves as the department lead. To perform the rework, the employee had to manually feed the parts into the chuck jaw without using feeder bowl. While he inserted the first part into the chuck jaw, the oily part slipped off the spring mechanism just as the employee activated the chuck jaw with his left hand. The employee had his right hand in the jaw when it closed and caught his index finger. The employee was hospitalized with a deep laceration which later required amputation of his fingertip.