Threading Inserts API INTERNAL API SPEC 7 : 2001API NUT B A 30° 30° L 90° IPF API SCREW I.C. PITCHTHREADTPITAPER CATALOG NUMBERIPFRIGHT HAND SIZE DIMENSIONSLmmI.C.A B V-0.040 5 3 API5 403 IR22 2 3∕8" - 4 1∕2" REG 1.8 2.6 V-0.038R 4 2 API4 382 IR22 NC23-NC50 2.0 2.6 V-0.038R 4 3 API4 383 IR22 NC56-NC77 22 12.70 2.0 2.6 V-0.050 4 2 API4 502 IR22 6 5/8" REG 1.9 2.8 V-0.050 4 3 API4 503 IR22 5 1/2" , 7 5/8" , 8 5/8" REG 1.9 2.8 V-0.040 5 3 API5 403 IR27 2 3∕8" - 4 1∕2" REG 1.9 2.7 V-0.038R 4 2 API4 382 IR27 NC23-NC50 2.2 2.8 V-0.038R 4 3 API4 383 IR27 NC56-NC77 27 15.875 2.2 2.8 V-0.050 4 2 API4 502 IR27 6 5/8" REG 2.2 3.0 V-0.050 4 3 API4 503 IR27 5 1/2" , 7 5/8" , 8 5/8" REG 2.2 3.0 47