https://www.ojp.gov/ncjrs/virtual-library/abstracts/unusual-suicide-chainsaw

A 32-year-old Asian woman with a significant medical history of major depression and schizophrenia who had been under treatment for 10 years committed suicide by an ingenious use of a chainsaw. She was found dead in her apartment where she lived alone. She was an engineer, but had shown no apparent interest in power tools. She designed an efficient and complex system for committing suicide. She put her head under a structure composed of pulleys and bags filled with full water bottles in order to weigh down the chainsaw. The chainsaw rested at the upper part of the structure on two horizontal wood boards sandwiched tightly between two other vertical wood boards in order to guide the chainsaw and avoid vibration and motion. The entire structure was approximately 1.5 m high. The chainsaw was positioned to slide slowly due to the pulleys and elastics fixed with clinched nails on the floor. Measurements had been made to ensure that the joints were square and the beams parallel. An electric command switch on the chainsaw was found in the right hand of the deceased. It allowed the chainsaw to cut the two horizontal wood planks and slide down the structure in a controlled manner. The deceased laid face down on the floor, and the chainsaw cut through her cervical spine and spinal cord. This report describes the procedure and findings of the autopsy, including a dry-bone study. The latter was necessary for understanding the mechanism and physiopathology of the death. The analysis of the death scene, the autopsy, and the dry-bone study enabled the pathologist to certify the manner of death as suicide.

(http://www.autoadmit.com/thread.php?thread_id=5700097&forum_id=2:#48784397)