Semi-tubular rivets and method of using

A rivet, that when formed joins laminates containing reinforced plastic with a double flush head and without the rivet expanding against the bore of the reinforced plastic, the rivet comprises:

• an alloy of about 55% titanium and about 45% columbium, a manufactured flush head, a constant diameter shank having an open end with tubular walls along part of its length, and the inside wall tapers outward at an angle of about 15 degrees to permit the end of the shank to be deformed outward to fill a countersink area without exerting outward pressure throughout the balance of the shank.

A method of joining parts at least one of which is a fiber reinforced plastic laminate, the steps comprising:

• drilling a hole through parts to be joined and countersinking on at least one side, selecting a semi-tubular rivet of titanium columbium alloy having a head and having an inside wall on the tubular portion that tapers outwardly at about 15 degrees, inserting the rivet with a net to a clearance fit in the hole in the parts, insuring that the open end of the tubular rivet is on the countersink side, placing a die on the open end with said die tapered at an angle greater than the angle of the countersink, and squeezing the rivet at a pressure sufficient to set the rivet by forming the open end of the rivet against the countersink.