machine bolt n a bolt with a square or hexagonal head on one end and a threaded shaft on the other end; tightened with a wrench; used to connect metal parts
News & Articles machine bolt Man, 51, sentenced to 62 years in deadly machine-bolt attack Fifty-one-year-old Clyde Johnson Jr. is likely to spend the rest of his life in prison for an attack with a 2-foot-long machine bolt. Sept. 27, 2013 - The Wichita Eagle