Thread Reference Charts: BSPP Metric SAE

British Standard Pipe(BSPP, BSPF) Thread Form

DASH SIZE	NOMINAL THREAD SIZE (T.P.I.)	BASIC DEPTH OF THREAD (h) (in.)	BASIC MAJOR DIA. (in.)	BASIC EFFECTIVE DIA. (in.)	BASIC MINOR DIA. (in.)	RECOMMENDED TAP DRILL SIZE
DASH SIZE	NOMINAL THREAD SIZE (T.P.I.)	BASIC DEPTH OF THREAD (h) (in.)	BASIC MAJOR DIA. (in.)	BASIC EFFECTIVE DIA. (in.)	BASIC MINOR DIA. (in.)	SIZE RP (mm)	Size G (mm)
-1	1/16-28	.0229	.304	.2812	.2583	6.60	6.80
-2	1/8-28	.0229	.383	.3601	.3372	8.60	8.80
-4	1/4-19	.0337	.518	.4843	.4506	11.50	11.80
-6	3/8-19	.0337	.656	.6223	.5886	15.00	15.25
-8	1/2-14	.0457	.825	.7793	.7336	18.50	19.00
-10	5/8-14	.0457	.902	.8563	.8106	-	21.00
-12	3/4-14	.0457	1.041	.9953	.9496	24.00	24.50
-14	7/8-14	.0457	1.189	1.1433	1.0976	-	23.25
-16	1-11	.0582	1.309	1.2508	1.1926	30.25	30.75
-20	1 1/4-11	.0582	1.650	1.5918	1.5336	39.00	39.50
-24	1 1/2-11	.0582	1.882	1.8238	1.7656	45.00	45.00
-28	1 3/4-11	.0582	2.116	2.0578	1.9996	-	51.00
-32	2-11	.0582	2.347	2.2888	2.2306	56.50	57.00
-36	2 1/4-11	.0582	2.587	2.5288	2.4706	No Sizes of B.S. (British Standard) drills are recommended in B.S. 1157:1975 for this range
-40	2 1/2-11	.0582	2.960	2.9018	2.8436
-44	2 3/4-11	.0582	3.210	3.1518	3.0936
-48	3-11	.0582	3.460	3.4018	3.3436
-52	3 1/4-11	.0582	3.700	3.6418	3.5836
-56	3 1/2-11	.0582	3.950	3.8918	3.8336
-60	3 3/4-11	.0582	4.200	4.1418	4.0836
-64	4-11	.0582	4.450	4.3918	4.3336

Tube Size (mm)	AL Series	LL Series	L Series	S Series	A Series	AG Series	DIN 7631 60 degree cone
4	M 8 X 0.75	M 8 X 1.0	----	----	M 10 X 1.5	----	M 12 X 1.5
6	M 10 X 1.0	M 10 X 1.0	M 12 X 1.5	M 14 X 1.5	M 12 X 1.0	----	M 14 X 1.5
8	M 12 X 1.0	M 12 X 1.0	M 14 X 1.5	M 16 X 1.5	M 14 X 1.5	----	M 16 X 1.5
10	M 14 X 1.0	M 14 X 1.0	M 16 X 1.5	M 18 X 1.5	M 16 X 1.5	----	M 18 X 1.5
12	M 16 X 1.0	M 16 X 1.0	M 18 X 1.5	M 20 X 1.5	M 18 X 1.5	----	M 22 X 1.5
13	----	----	----	----	----	M 20 X 1.5	----
14	M 18 X 1.0	----	----	M 22 X 1.5	M 20 X 1.5	----	----
15	M 20 X 1.0	----	M 22 X 1.5	----	M 22 X 1.5	----	----
16	M 22 X 1.0	----	----	M 24 X 1.5	M 24 X 1.5	----	M 26 X 1.5
17	----	----	----	----	----	M 24 X 1.5	----
18	M 24 X 1.0	----	M 26 X 1.5	----	M 27 X 1.5	----	----
20	M 25 X 1.0	----	----	M 30 X 2.0	M 27 X 1.5	----	M 30 X 1.5
21	----	----	----	----	----	M 30 X 1.5	----
22	----	----	M 30 X 2.0	----	M 30 X 1.5	----	----
25	----	----	----	M 36 X 2.0	M 33 X 1.5	----	M 38 X 1.5
27	----	----	----	----	----	M 36 X 1.5	----
28	----	----	M 36 X 2.0	----	M 36 X 1.5	----	----
30	----	----	----	M 42 X 2.0	M 39 X 1.5	----	----
32	----	----	----	----	----	----	M 45 X 1.5
33	----	----	----	----	----	M 45 X 1.5	----
35	----	----	M 45 X 2.0	----	M 45 X 1.5	----	----
38	----	----	----	M 52 X 2.0	M 48 X 1.5	----	----
40	----	----	----	----	M 52 X 1.5	----	M 52 X 1.5
42	----	----	M 52 X 2.0	----	----	M 52 X 1.5	----
45	----	----	----	----	M 54 X 2.0	----	----
48	----	----	----	----	M 58 X 2.0	----	----
49	----	----	----	----	----	M 58 X 2.0	----

American National Pipe Taper (NPT) Thread Form

Dash Size	Nominal Thread Size - t.p.i.	Basic depth of thread (h) (in.)	Outside dia. of pipe (in.)	Effective diameter at small end of external thread (in.)	Basic Minor Dia. (in.)	Recommended tap drill size (mm)
-1	1/16 - 27	.0296	.3125	.2712	.2812	6.30
-2	1/8 - 27	.0296	.405	.3635	.3736	8.70
-4	1/4 - 18	.0444	.540	.4774	.4916	11.10
-6	3/8 - 18	.0444	.675	.6120	.6270	14.50
-8	1/2 - 14	.0571	.840	.7584	.7784	18.00
-12	3/4 - 14	.0571	1.050	.9677	.9889	23.25
-16	1 - 11-1/2	.0696	1.315	1.2136	1.2386	29.00
-20	1 1/4 - 11-1/2	.0696	1.660	1.5571	1.5834	38.00
-24	1 1/2 - 11-1/2	.0696	1.900	1.7961	1.8223	44.00
-32	2 - 11-1/2	.0696	2.375	2.2690	2.2963	56.00
-40	2 1/2 - 8	.1000	2.875	2.7195	2.7622	67.00

Dash Size	Nominal Size	Threads per In.	Male Thread O.D.	Female Thread I.D.
-4	7/16	20	7/16	25/64
-5	1/2	20	1/2	29/64
-6	9/16	18	9/16	1/2
-8	3/4	16	3/4	11/16
-10	7/8	14	7/8	13/16
-12	1-1/16	12	1-1/16	31/32
-16	1-5/16	12	1-5/16	1-15/64
-20	1-5/8	12	1-5/8	1-35/64
-24	1-7/8	12	1-7/8	1-51/64
-32	2-1/2	12	2-1/2	2-27/64

Dash Size	Nominal Size	Threads per In.	Male Thread O.D.	Female Thread I.D.
-4	7/16	20	7/16	25/64
-5	1/2	20	1/2	29/64
-6	9/16	18	9/16	1/2
-8	3/4	16	3/4	11/16
-10	7/8	14	7/8	13/16
-12	1-1/16	12	1-1/16	1-63/64
-16	1-5/16	12	1-5/16	1-15/64
-20	1-5/8	12	1-5/8	1-35/64
-24	1-7/8	12	1-7/8	1-51/64
-32	2-1/2	12	2-1/2	2-27/64

Dash Size	Nominal Size	Threads per In.	Male Thread O.D.	Female Thread I.D.
-4	9/16	18	9/16	1/2
-6	11/16	16	11/16	5/8
-8	13/16	16	13/16	3/4
-10	1	14	1	15/16
-12	1-3/16	12	1-3/16	1-3/32
-16	1-7/16	12	1-7/16	1-11/32
-20	1-11/16	12	1-11/16	1-19/32
-24	2	12	2	1-29/32

Dash Size	Nominal Size	Threads per In.	Male Thread O.D.	Female Thread I.D.
-4	7/16	20	7/16	25/64
-5	1/2	20	1/2	29/64
-6	5/8	18	5/8	9/16
-8	3/4	16	3/4	11/16
-10	7/8	14	7/8	13/16
-12	1-1/16	14	1-1/16	63/64

Nom. Tube O.D. (in.)	Dash Size	Nominal Size	Threads per In.	Male Thread O.D.	Female Thread I.D.
1/8	-2	5/16	24	5/16	17/64
3/16	-3	3/8	24	3/8	21/64
1/4	-4	7/16	20	7/16	25/64
5/16	-5	1/2	20	1/2	29/64
3/8	-6	9/16	18	9/16	1/2
1/2	-8	3/4	16	3/4	11/16
5/8	-10	7/8	14	7/8	13/16
3/4	-12	1-1/16	12	1-1/16	31/32
1	-16	1-5/16	12	1-5/16	1-15/64
1 1/4	-20	1-5/8	12	1-5/8	1-35/64
1 1/2	-24	1-7/8	12	1-7/8	1-51/64
2	-32	2-1/2	12	2-1/2	2-27/64