THREAD IDENTIFICATION CHART -- PART 3

The British thread system is fractionally based, but all thread vee angles are different than the American fractionally or decimally based threads. Most thread per inch values are different than in the American System.
Taper pipe thread major diameters are measured at the guage point.
(H)= BSPT copper pipe thread.
Dimensions within ( ) in the M FINE column are obsolete French or Japanese threads.
Dimensions within ( ) in the BSW column are obsolete British coarse threads.
The 6.3 mm dimension; marked GM is an obsolete General Motors thread.

TABLE (SD) -- SPECIAL USE THREAD DEFINITIONS

C =	Compression fittings
J =	JIC 37 degree Flare fittings
F =	JIC 45 degree Flare fittings
SAE =	SAE straight thread
NF =	National Fine thread
E =	Electrical thread

WARNING: We are not responsible for any technical errors or typographical errors in this publication.

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BASIC MAJOR DIAMETER		NOMINAL DIAMETER METRIC	STD. REF.	METRIC -- PITCH in mm			NOMINAL DIAMETER AMERICAN	AMERICAN -- PITCH in THREADS per Inch					SPECIAL USE NOTES*	NOMINAL DIAMETER BRITISH	BRITISH -- PITCH in THREADS per Inch
Inch	mm	mm	.	COARSE	FINE	M TAPER	FRACTIONS	UNC	UNF	UNEF	NPT	8UN	*See table SD	FRACTIONS	BSW	BSF	BSPF	BSPT
0.3108	7.894	.	.	.	.	.	1/16	.	.	.	27	.	.	.	.	.	BSPP	.
0.3125	7.94	.	.	.	.	.	5/16	18	24	32	.	.	24(C-J) 24(SAE-F)	5/16	18	22	.	.
0.3150	8.00	8	I D	1.25	0.5,0.75,1	1	.	.	.	.	.	.	.	.	.	.	.	.
0.3543	9.00	9	III D	1.25	0.75,1	.	.	.	.	.	.	.	.	.	.	.	.	.
0.3750	9.53	.	.	.	.	.	3/8	16	24	32	.	.	24(SAE C-J)	3/8	16	20	.	.
0.3830	9.73	.	.	.	.	.	.	.	.	.	.	.	.	1/8	.	.	28	28
0.3937	10.00	10	I D	1.5	0.75,1,1.25	1	.	.	.	.	.	.	.	.	.	.	.	.
0.4044	10.271	.	.	.	.	.	1/8	.	.	.	27	.	.	.	.	.	.	.
0.4331	11.00	11	III D	1.5	0.75,1,1.25	.	.	.	.	.	.	.	.	.	.	.	.	.
0.4375	11.11	.	.	.	.	.	7/16	14	20	28	.	.	24(C) 20(SAE J-F)	7/16	14	18	.	.
0.4724	12.00	12	I D	1.75	1,1.25,1.5	1.5	.	.	.	.	.	.	.	.	.	.	.	.
0.5000	12.70	.	.	.	.	.	1/2	13	20	28	.	.	24(C) 20(SAE J-F)	1/2	12	16	.	.
0.5180	13.16	.	.	.	.	.	.	.	.	.	.	.	.	1/4	.	.	19	19
0.5343	13.571	.	.	.	.	.	.	.	.	.	18	.	.	.	.	.	.	.
0.5512	14.00	14	II D	2	1,1.25,1.5	.	.	.	.	.	.	.	.	.	.	.	.	.
0.5625	14.29	.	.	.	.	.	9/16	12	18	24	.	.	24(C) 18(SAE-J)	9/16	12	16	.	.
0.5906	15.00	15	III D	.	1,1.5	.	.	.	.	.	.	.	.	.	.	.	.	.
0.6250	15.88	.	.	.	.	.	5/8	11	18	24	.	.	24(C) 18(SAE-F)	5/8	11	14	.	.
0.6299	16.00	16	I D	2	1,1.5	1.5	.	.	.	.	.	.	.	.	.	.	.	.
0.6560	16.662	.	.	.	.	.	.	.	.	.	.	.	.	3/8	.	.	19	19
0.6693	17.00	17	III D	.	1,1.5	.	.	.	.	.	.	.	.	.	.	.	.	.
0.6714	17.054	.	.	.	.	.	3/8	.	.	.	18	.	.	.	.	.	.	.
0.6875	17.46	.	.	.	.	.	11/16	.	.	24	.	.	20(C) 18(SAE-F)	11/16	11	14	.	.
0.7087	18.00	18	II D	2.5	1,1.5,2	1.5	.	.	.	.	.	.	.	.	.	.	.	.
0.7500	19.05	.	.	.	.	.	3/4	10	16	20	.	.	16(SAE-J-F)	3/4	10	12	.	.
0.7874	20.00	20	I D	2.5	1,1.5,2	1.5	.	.	.	.	.	.	.	.	.	.	.	.
0.8125	20.64	.	.	.	.	.	13/16	.	.	20	.	.	18(C)	13/16	10	12	.	.
0.8250	20.955	.	.	.	.	.	.	.	.	.	.	.	.	1/2	.	.	14	14
0.8356	21.222	.	.	.	.	.	1/2	.	.	.	14	.	.	.	.	.	.	.
0.8661	22.00	22	II D	2.5	1,1.5,2	1.5	.	.	.	.	.	.	.	.	.	.	.	.
0.8750	22.23	.	.	.	.	.	7/8	9	14	20	.	.	14(SAE-F-J)	7/8	9	11	.	.
0.9020	22.911	.	.	.	.	.	.	.	.	.	.	.	.	5/8	.	.	14	14
0.9375	23.81	.	.	.	.	.	15/16	.	.	20	.	.	20(C-J) 16(SAE)	15/16	9	.	.	.
0.9449	24.00	24	I D	3	1,1.5,2	.	.	.	.	.	.	.	.	.	.	.	.	.
0.9843	25.00	25	III D	.	1,1.5,2	.	.	.	.	.	.	.	.	.	.	.	.	.
1.0000	25.40	.	.	.	.	.	1	8	12	20	.	8	18(C) 14(NF)	1	8	10	.	.
1.0236	26.00	26	III D	.	1.5	1.5	.	.	.	.	.	.	.	.	.	.	.	.
1.0410	26.441	.	.	.	.	.	.	.	.	.	.	.	.	3/4	.	.	14	14
1.0460	26.568	.	.	.	.	.	3/4	.	.	.	14	.	.	.	.	.	.	.
1.0625	26.99	.	.	.	.	.	1 1/16	.	.	18	.	8	14(F) 12(SAE-J)	.	.	.	.	.
1.0630	27.00	27	II D	3	1,1.5,2	.	.	.	.	.	.	.	.	.	.	.	.	.
1.1024	28.00	28	III D	.	1,1.5,2	.	.	.	.	.	.	.	.	.	.	.	.	.
1.1250	28.58	.	.	.	.	.	1 1/8	7	12	18	.	8	18(C)	1 1/8	7	9	.	.
1.1811	30.00	30	I D	3.5	1,1.5,2,3	.	.	.	.	.	.	.	.	.	.	.	.	.
1.1875	30.16	.	.	.	.	.	1 3/16	.	.	18	.	8	12(SAE-J)	.	.	.	.	.
1.1890	30.20	.	.	.	.	.	.	.	.	.	.	.	.	7/8	.	.	14	14
1.2500	31.75	.	.	.	.	.	1 1/4	7	12	18	.	8	12(SAE)	1 1/4	7	9	.	.
1.2598	32.00	32	III D	.	1.5,2	.	.	.	.	.	.	.	.	.	.	.	.	.
1.2992	33.00	33	II D	3.5	1.5,2,3	.	.	.	.	.	.	.	.	.	.	.	.	.
1.3328	33.228	.	.	.	.	.	1	.	.	.	11 1/2	.	.	.	.	.	.	.
1.3090	33.249	.	.	.	.	.	.	.	.	.	.	.	.	1	.	.	11	11
1.3125	33.34	.	.	.	.	.	1 5/16	.	.	18	.	8	12(SAE-J)	.	.	.	.	.
1.3750	34.93	.	.	.	.	.	1 3/8	6	12	18	.	8	.	1 3/8	6	8	.	.
1.3780	35.00	35	III D	.	1.5	.	.	.	.	.	.	.	SEE TABLE	.	.	.	.	.
1.4173	36.00	36	I D	4	1.5,2,3	.	.	.	.	.	.	.	SD	.	.	.	.	.
1.4375	36.51	.	.	.	.	.	1 7/16	.	.	18	.	8	FOR	.	.	.	.	.
1.4920	37.897	.	.	.	.	.	.	.	.	.	.	.	SPECIAL	1 1/8	.	.	11	.
1.4961	38.00	38	III D	.	1.5	.	.	.	.	.	.	.	USE	.	.	.	.	.
1.5000	38.10	.	.	.	.	.	1 1/2	6	12	18	.	8	DEFINITIONS	1 1/2	6	8	.	.
1.5354	39.00	39	II D	4	1.5,2,3	.	.	.	.	.	.	.	.	.	.	.	.	.
1.5625	39.69	.	.	.	.	.	1 9/16	.	.	18	.	8	.	.	.	.	.	.
1.5748	40.00	40	III D	.	1.5,2,3	.	.	.	.	.	.	.	.	.	.	.	.	.
1.6250	41.28	.	.	.	.	.	1 5/8	.	.	18	.	8	12(SAE-J)	1 5/8	5	8	.	.
1.6500	41.91	.	.	.	.	.	.	.	.	.	.	.	.	1 1/4	.	.	11	11
1.6535	41.99	42	I D	4.5	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
1.6600	42.16	.	.	.	.	.	1 1/4	.	.	.	11 1/2	.	.	.	.	.	.	.
1.6875	42.86	.	.	.	.	.	1 11/16	.	.	18	.	8	.	.	.	.	.	.
1.7450	44.32	.	.	.	.	.	.	.	.	.	.	.	.	1 3/8	.	.	11	.
1.7500	44.45	.	.	16	.	.	1 3/4	5	.	16	.	8	.	1 3/4	5	7	.	.
1.7717	45.00	45	II D	4.5	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
1.8750	47.63	.	.	.	.	.	1 7/8	.	.	.	.	8	12(SAE-J)	1 7/8	4 1/2	.	.	.
1.8820	47.802	.	.	.	.	.	.	.	.	.	.	.	.	1 1/2	.	.	11	11
1.8898	48.00	48	I D	5	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
1.8919	48.054	.	.	.	.	.	1 1/2	.	.	.	11 1/2	.	.	.	.	.	.	.
1.9685	50.00	50	III D	.	1.5,2,3	.	.	.	.	.	.	.	.	.	.	.	.	.
2.0000	50.80	.	.	.	.	.	2	4 1/2	.	16	.	8	.	2	4 1/2	7	.	.
2.0472	52.00	52	II D	5	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
2.1654	55.00	55	III D	.	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
2.2047	56.00	56	I D	5.5	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
2.2500	57.15	.	.	.	.	.	2 1/4	4 1/2	.	.	.	8	.	2 1/4	4	6	.	.
2.2835	58.00	58	III D	.	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
2.3470	59.613	.	.	.	.	.	.	.	.	.	.	.	.	2	.	.	11	11
2.3622	60.00	60	II D	5.5	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
2.3658	60.094	.	.	.	.	.	2	.	.	.	11 1/2	.	.	.	.	.	.	.
2.4409	62.00	62	III D	.	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
2.5000	63.50	.	.	.	.	.	2 1/2	4	.	.	.	8	12(SAE-J)	2 1/2	4	6	.	.
2.5197	64.00	64	I D	6	1.5,2,3,4	.	.	.	.	.	.	.	.	.	.	.	.	.
Metric Electrical thread
2.4803	63.00	63	.	.	1.5	.	.	.	.	.	.	.	E	.	.	.	.	.
2.9528	75.00	75	.	.	1.5	.	.	.	.	.	.	.	E	.	.	.	.	.
3.1496	80.00	80	.	.	2	.	.	.	.	.	.	.	E	.	.	.	.	.
3.3465	85.00	85	.	.	2	.	.	.	.	.	.	.	E	.	.	.	.	.
3.5433	90.00	90	.	.	2	.	.	.	.	.	.	.	E	.	.	.	.	.
3.937	100.00	100	.	.	2, 3	.	.	.	.	.	.	.	E	.	.	.	.	.
4.3307	110.00	110	.	.	2	.	.	.	.	.	.	.	E	.	.	.	.	.

MARYLAND METRICS -- THREAD IDENTIFICATION CHART SECTION (A): FOR MAJOR DIAMETERS FROM 7.894 mm to 64 mm + Electrical thread to 110 mm Continuation: (Also see the IMPORTANT notes at the bottom of this table.)

TABLE (SD) -- SPECIAL USE THREAD DEFINITIONS

MARYLAND METRICS -- THREAD IDENTIFICATION CHART SECTION (A):
FOR MAJOR DIAMETERS FROM 7.894 mm to 64 mm + Electrical thread to 110 mm
Continuation: (Also see the IMPORTANT notes at the bottom of this table.)