A repair coupling for joining a first pipe with a second pipe includes (a) a hollow body having a first open end, a second open end, and a passageway the interior surface of the body defining a peripheral, helical body edge terminating in a body edge locking lug, and (b) a hollow tubular insert slidably disposed within the body, the tubular insert having a first open end and a second open end, the tubular insert defining a passageway he exterior surface of the tubular insert defining a peripheral, helical insert edge terminating in an insert edge locking lug. The tubular insert is slidable between (i) a first insert position wherein the helical insert edge is in contract with the helical body edge and (ii) a second insert position wherein the helical insert edge is spaced apart from the helical body edge.