Greg Mote: Mechanical Reference: ISO Thread

nominal			minor	tap size
Ø	pitch	series	Ø	Ø
1	0.25	coarse	0.729	0.75
2	0.40	coarse	1.567	1.60
3	0.35	fine	2.621	2.65
3	0.50	coarse	2.459	2.50
4	0.50	fine	3.459	3.50
4	0.70	coarse	3.242	3.30
5	0.50	fine	4.459	4.50
5	0.80	coarse	4.134	4.20
6	0.75	fine	5.188	5.20
6	1.00	coarse	4.917	5.00
7	0.75	fine	6.188	6.20
7	1.00	coarse	5.917	6.00
8	0.75	fine	7.188	7.20
8	1.00	?	6.918	7.00
8	1.25	coarse	6.647	6.80
9	0.75	fine	8.188	8.20
9	1.00	?	7.918	8.00
9	1.25	coarse	7.647	7.80
10	0.75	fine	9.188	9.20
10	1.50	coarse	8.376	8.50
11	0.75	fine	10.188	10.20
11	1.50	coarse	9.37	9.50
12	1.75	coarse	10.106	10.20
14	2.00	coarse	11.835	12.00
16	2.00	coarse	13.835	14.00
18	2.50	coarse	15.294	15.50
20	2.50	coarse	17.294	17.50
22	2.50	coarse	19.294	19.50
24	3.00	coarse	20.752	21.00
27	3.00	coarse	23.752	24.00
30	3.50	coarse	26.211	26.50
33	3.50	coarse	29.211	29.50
36	4.00	coarse	31.670	32.00
39	4.00	coarse	34.670	35.00
42	4.50	coarse	37.129	37.50
45	4.50	coarse	40.129	40.50