ragbolt

ragbolt

(ˈræɡˌbəʊlt)
n
(Building) a bolt that has angled projections on it to prevent it working loose once it has been driven home
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014