Patent ID: 6991268

Claim:
A pipe fitting comprising: (a) a body having a bore terminating in a bore opening, the bore opening being threaded with a plurality of internal tapered bore threads of a first material, the tapered bore threads having successively smaller threaded bore thread pitch diameters and include a first tapered bore thread which is disposed closest to the bore opening and which has a pitch diameter which is larger than that of the other tapered bore threads; and (b) at least one starter thread disposed either within the bore and being closer to the bore opening than the tapered bore threads or being disposed immediately outside of the bore, the at least one starter thread being axially aligned with the tapered bore threads and being of a second material which is stronger than the first material, the at least one starter thread including a last tapered starter thread disposed closest to the tapered bore threads; wherein the last starter thread has a pitch diameter which is at least 2% greater than the pitch diameter of the first bore thread.