28UN 28UNR Thread Chart

Measured in Inches
Size Primary Inch	Basic Major Diameter Inch	Basic Pitch Diameter Inch	Minor Diameter, inch		Minor Dia. Area sq. inch	Tensile Stress Area sq. inch
Size Primary Inch	Basic Major Diameter Inch	Basic Pitch Diameter Inch	External Thread	Internal Thread	Minor Dia. Area sq. inch	Tensile Stress Area sq. inch
#12	0.216	0.1928	0.1734	0.1773	0.0226	0.0258
1/4	0.25	0.2268	0.2074	0.2113	0.0326	0.0364
5/16	0.3125	0.2893	0.2699	0.2738	0.0556	0.0606
3/8	0.375	0.3518	0.3324	0.3363	0.0848	0.0909
7/16	0.4375	0.4143	0.3949	0.3988	0.1201	0.1274
1/2	0.5	0.4768	0.4574	0.4613	0.162	0.17
9/16	0.5625	0.5393	0.5199	0.5238	0.209	0.219
5/8	0.625	0.6018	0.5824	0.5863	0.263	0.274
11/16	0.6875	0.6643	0.6449	0.6488	0.323	0.335
3/4	0.75	0.7268	0.7074	0.7113	0.389	0.402
13/16	0.8125	0.7893	0.7699	0.7738	0.461	0.475
7/8	0.875	0.8518	0.8324	0.8363	0.539	0.554
15/16	0.9375	0.9143	0.8949	0.8988	0.624	0.64
1	1	0.9768	0.9574	0.9613	0.714	0.732
1-1/16	1.0625	1.0393	1.0199	1.0238	0.811	0.83
1-1/8	1.125	1.1018	1.0824	1.0863	0.914	0.933
1-3/16	1.1875	1.1643	1.1449	1.1488	1.023	1.044
1-1/4	1.25	1.2268	1.2074	1.2113	1.138	1.16
1-5/16	1.3125	1.2893	1.2699	1.2738	1.259	1.282
1-3/8	1.375	1.3518	1.3324	1.3363	1.386	1.411
1-7/16	1.4375	1.4143	1.3949	1.3988	1.52	1.55
1-1/2	1.5	1.4768	1.4574	1.4613	1.66	1.69