NPSC	(USAS B2.1-1968)
External	Nominal	Pitch	Major	Major		Internal	Nominal	Pitch	Major	Major
	Size	TPI	Diameter	Diameter			Size	TPI	Diameter	Diameter
			(Inch)	(MM)					(Inch)	(MM)
	1/8	27	0.4021	10.212			1/8	27	0.3951	10.035
	1/4	18	0.5351	13.592			1/4	18	0.5247	13.328
	3/8	18	0.6705	17.031			3/8	18	0.6601	16.767
	1/2	14	0.8358	21.230			1/2	14	0.8224	20.889
	3/4	14	1.0463	26.576			3/4	14	1.0329	26.236
	1	11.5	1.3094	33.259			1	11.5	1.2931	32.845
	1 1/4	11.5	1.6541	42.014			1 1/4	11.5	1.6378	41.600
	1 1/2	11.5	1.8931	48.085			1 1/2	11.5	1.8768	47.671
	2	11.5	2.3670	60.122			2	11.5	2.3507	59.708
	2 1/2	8	2.8667	72.813			2 1/2	8	2.8432	72.216
	3	8	3.4930	88.721			3	8	3.4696	88.127
	3 1/2	8	3.9933	101.429			3 1/2	8	3.9699	100.834
	4	8	4.4916	114.085			4	8	4.4682	113.491