Installing the 14 rivnuts in the rear spar doublers today came to an abrupt halt on the third one when the threaded mandrel of the rivnut tool pulled straight thruogh the rivnut removing the crests of the thread before the rivnut was properly set. I'm pretty sure this was caused by the mandrel being slightly undersize. I will source a better quality tool tommorow. I drilled the bad rivnut out, deburred the hole and will attempt to realodine the area around the hole before continueing.
