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UNC - Unified National Coarse

Dia	TPI	Tapping Drill	Clearance Drill
1	64	1.55	1.95
2	56	1.85	2.3
3	48	2.10	2.65
4	40	2.35	2.95
5	40	2.65	3.3
6	32	2.85	3.6
8	32	3.5	4.3
10	24	3.9	5.0
12	24	4.5	5.6
1/4	20	5.2	6.5
5/16	18	6.6	8.1
3/8	16	8	9.7
7/16	14	9.4	11.3
1/2	13	10.80	12.90
9/16	12	12.20	14.50
5/8	11	13.50	41/64
3/4	10	16.50	49/64
7/8	9	19.50	57/64
1	8	22.25	1-1/64
1-1/8	7	25.00	1-9/64
1-1/4	7	28.00	1-17/64
1-3/8	6	30.75	1-25/64
1-1/2	6	34.00	1-33/64
1-3/4	5	39.50	1-49/64
2	4.5	45.00	2-1/64

 

UNF - Unified National Fine

Dia	TPI	Tapping Drill	Clearance Drill
0	80	1.25	1.65
1	72	1.55	1.95
2	64	1.90	2.3
3	56	2.15	2.65
4	48	2.40	2.95
5	44	2.70	3.3
6	40	2.95	3.6
8	36	9/64	4.3
10	32	4.1	5.0
12	28	4.7	5.6
1/4	28	5.5	6.5
5/16	24	6.9	8.1
3/8	24	8.5	9.7
7/16	20	9.9	11.3
1/2	20	11.50	12.9
9/16	18	12.90	14.5
5/8	18	14.50	41/64
3/4	16	11/16	49/64
7/8	14	20.40	57/64
1	12	23.25	1-1/64
1-1/8	12	26.50	1-9/64
1-1/4	12	29.50	1-17/64
1-3/8	12	32.75	1-25/64
1-1/2	12	36	1-33/64

 

BSW - British Standard Whitworth

Dia	TPI	Tapping Drill	Clearance Drill
1/16	60	1.25	1.85
3/32	48	1.95	2.6
1/8	40	2.55	3.5
5/32	32	1/8	4.3
3/16	24	3.7	5.1
7/32	24	4.5	5.9
1/4	20	5.1	6.7
5/16	18	6.5	8.3
3/8	16	5/16	25/64
7/16	14	9.3	11.5
1/2	12	10.5	33/64
9/16	12	12.1	14.75
5/8	11	13.5	16.5
11/16	11	15.25	18
3/4	10	41/64	19.5
13/16	10	18	21.25
7/8	9	19.25	22.75
15/16	9	21	24.25
1	8	22	1-1/32
1-1/8	7	24.75	1-5/32
1-1/4	7	1-3/32	1-9/32
1-3/8	6	31	1-13/32
1-1/2	6	33.5	1-17/32
1-5/8	5	36.5	1-21/32
1-3/4	5	39	1-25/32
1-7/8	4.5	41.5	1-29/32
2	4.5	44.5	2-1/32

 

BSF - British Standard Fine

Dia	TPI	Tapping Drill	Clearance Drill
3/16	32	5/32	5
7/32	28	4.6	5.7
1/4	26	5.3	6.5
9/32	26	6.1	7.4
5/16	22	6.8	8.2
3/8	20	8.3	9.7
7/16	18	9.7	11.4
1/2	16	7/16	13
9/16	16	1/2	14.5
5/8	14	14	41/64
11/16	14	15.75	45/64
3/4	12	16.75	49/64
13/16	12	18.5	21
7/8	11	25/32	57/64
1	10	22.75	1-1/64
1-1/8	9	25.5	1-9/64
1-1/4	9	1-1/8	1-17/64
1-3/8	8	31.5	1-25/64
1-1/2	8	1-23/64	1-33/64
1-5/8	8	1-31/64	1-41/64
1-3/4	7	1-39/64	1-49/64
2	7	1-27/32	2-1/32
2-1/4	6	2-1/16	2-9/32
2-1/2	6	2-5/16	2-17/32
2-3/4	6	2-9/16	2-25/32
3	5	2-25/32	3-1/32

 

Metric Coarse

Dia	TPI	Tapping Drill	Clearance Drill
1	0.25	0.75	1.05
1.1	0.25	0.85	1.15
1.2	0.25	0.95	1.25
1.4	0.30	1.10	1.45
1.6	0.35	1.25	1.65
1.8	0.35	1.45	1.85
2	0.40	1.6	2.05
2.2	0.45	1.75	2.25
2.5	0.45	2.05	2.60
3	0.50	2.5	3.10
3.5	0.60	2.9	3.60
4	0.70	3.30	4.10
4.5	0.75	3.70	4.60
5	0.80	4.2	5.10
6	1.00	5.0	6.10
7	1.00	6.0	7.20
8	1.25	6.8	8.20
9	1.25	7.8	9.20
10	1.50	8.5	10.20
11	1.50	9.5	11.20
12	1.75	10.20	12.20
14	2.00	12.00	14.25
16	2.00	14.00	16.25
18	2.50	15.50	18.25
20	2.50	17.50	20.25
22	2.50	19.50	22.25
24	3.00	21.00	24.25
27	3.00	24.00	27.25
30	3.50	26.50	30.50
33	3.50	29.50	33.50
36	4.00	32.00	36.50
39	4.00	35.00	39.50
42	4.50	37.50	42.50
45	4.50	40.50	45.50
48	5.00	43.00	48.50
52	5.00	47.00	53.00
56	5.50	50.50	57.00

 

Metric Fine

Dia	TPI	Tapping Drill	Clearance Drill
2	0.25	1.75	2.05
2.2	0.25	1.95	2.25
2.5	0.35	2.15	2.60
3	0.35	2.65	3.10
3.5	0.35	3.15	3.60
4	0.50	3.50	4.10
4.5	0.50	4.00	4.60
5	0.50	4.50	5.10
6	0.75	5.20	6.10
7	0.75	6.20	7.20
8	0.75	7.20	8.20
8	1.00	7.00	8.20
9	0.75	8.20	9.20
9	1.00	8.00	9.20
*10	1.00	9.00	10.20
10	1.25	8.80	10.20
11	1.00	10.00	11.20
12	1.00	11.00	12.20
*12	1.25	10.80	12.20
12	1.50	10.50	12.20
14	1.00	13.00	14.25
*14	1.25	12.80	14.25
14	1.50	12.50	14.25
16	1.00	15.00	16.25
16	1.50	14.50	16.25
18	1.00	17.00	18.25
*18	1.50	16.50	18.25
18	2.00	16.00	18.25
20	1.00	19.00	20.25
20	1.50	18.50	20.25
20	2.00	18.00	20.25
22	1.00	21.00	22.25
22	1.50	20.50	22.25
22	2.00	20.00	22.25
24	1.00	23.00	24.25
24	1.50	22.50	24.25
24	2.00	22.00	24.25
25	1.50	23.50	25.25
25	2.00	23.00	25.25
27	1.50	25.50	27.25
28	1.50	26.50	28.50
30	1.50	28.50	30.50
32	1.50	30.50	32.50
33	2.00	31.00	33.50
36	3.00	33.00	36.50
39	3.00	36.00	39.50
40	1.50	38.50	40.50
40	3.00	37.00	40.50
42	4.00	38.00	42.50
45	4.00	41.00	45.50
48	4.00	44.00	48.50
52	4.00	48.00	53.00
56	4.00	52.00	57.00
60	4.00	56.00	61.00

 

B.A - British Association

BA No	TPI	Tapping Drill	Clearance Drill
0	25.38	5.1	1/4
1	28.25	4.5	5.5
2	31.36	4.0	4.9
3	34.84	3.4	11/64
4	38.46	3.0	3.8
5	43.10	2.65	3.4
6	47.85	2.3	3.0
7	52.91	2.05	2.7
8	59.17	1.8	3/32
9	64.94	1.65	2.1
10	72.46	1.4	1.8
11	81.97	1.2	1/16
12	90.91	1.05	1.45

 

BSP - British Standard Pipe

Size	TPI	Tapping Drill	Clearance Drill
1/8	28	8.8	10
1/4	19	11.8	13.5
3/8	19	15.25	17.25
1/2	14	3/4	21.25
5/8	14	53/64	23.5
3/4	14	24.5	1-3/64
7/8	14	28.25	1-13/64
1	11	30.75	1-11/32
1-1/4	11	39.5	1-11/16
1-1/2	11	1-25/32	1-29/32
1-3/4	11	51	2-5/32
2	11	2-1/4	2-23/64
2-1/4	11	2-31/64	2-5/8
2-1/2	11	2-55/64	3
2-3/4	11	3-7/64	3-15/64
3	11	3-23/64	3-1/2

 

UNEF - Unified National Extra Fine

Size	TPI	Tapping Drill	Clearance Drill
12	32	4.70	5.6
1/4	32	7/32	6.5
5/16	32	9/32	8.10
3/8	32	11/32	9.70
7/16	28	10.20	11.30
1/2	28	11.80	12.90
9/16	24	13.20	14.50
5/8	24	15	41/64
11/16	24	16.50	45/64
3/4	20	45/64	49/64
13/16	20	49/64	53/64
7/8	20	21	57/64
15/16	20	22.5	63/64
1	20	61/64	1-1/64

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