ASME B18.2.2 Heavy Hex Flat Nuts

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness, H			Bearing Surface Runout to Thread Axis, FIM
Nominal Size	Basic Major Diameter of Thread	Basic	Min.	Max.	Min.	Max.	Basic	Min.	Max.	Bearing Surface Runout to Thread Axis, FIM
1 1/8	28.575	46.038	44.602	46.025	50.851	53.162	28.575	27.407	29.337	0.813
1 1/4	31.750	50.800	49.225	50.800	56.109	58.649	31.750	30.150	32.563	0.864
1 3/8	34.925	55.563	53.823	55.575	61.366	64.160	34.925	33.274	35.789	0.965
1 1/2	38.100	60.325	58.420	60.325	66.599	69.647	38.100	36.398	39.014	1.041
1 3/4	44.450	69.850	67.615	69.850	77.089	80.645	44.450	42.647	45.466	1.219
2	50.800	79.375	76.835	79.375	87.605	91.643	50.800	48.895	51.918	1.372
2 1/4	57.150	88.900	86.055	88.900	98.095	102.641	57.150	54.737	58.369	1.549
2 1/2	63.500	98.425	95.250	98.425	108.585	113.640	63.500	60.985	64.821	1.702
2 3/4	69.850	107.950	104.445	107.950	119.075	124.638	69.850	67.234	71.272	1.880
3	76.200	117.475	113.665	117.475	129.591	135.636	76.200	73.482	77.724	2.032
3 1/4	82.550	127.000	122.885	127.000	140.081	146.660	82.550	79.350	84.176	2.210
3 1/2	88.900	136.525	132.080	136.525	150.571	157.658	88.900	85.598	90.627	2.362
3 3/4	95.250	146.050	141.275	146.050	161.061	168.656	95.250	91.846	97.079	2.540
4	101.600	155.575	150.495	155.575	171.577	179.654	101.600	98.095	103.530	26.924
All dimensions are in millimeters. Bold type indicates nuts unified dimensionally with British and Canadian Standards. Threads are Unified Coarse-thread series (UNC), Class 2B.

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness, H			Bearing Surface Runout to Thread Axis, FIM
Nominal Size	Basic Major Diameter of Thread	Basic	Min.	Max.	Min.	Max.	Basic	Min.	Max.	Bearing Surface Runout to Thread Axis, FIM
1 1/8	1.1250	1 13/16	1.756	1.812	2.002	2.093	1 1/8	1.079	1.155	0.032
1 1/4	1.2500	2	1.938	2.000	2.209	2.309	1 1/4	1.187	1.282	0.034
1 3/8	1.3750	2 3/16	2.119	2.188	2.416	2.526	1 3/8	1.310	1.409	0.038
1 1/2	1.5000	2 3/8	2.300	2.375	2.622	2.742	1 1/2	1.433	1.536	0.041
1 3/4	1.7500	2 3/4	2.662	2.750	3.035	3.175	1 3/4	1.679	1.790	0.048
2	2.0000	3 1/8	3.025	3.125	3.449	3.608	2	1.925	2.044	0.054
2 1/4	2.2500	3 1/2	3.388	3.500	3.862	4.041	2 1/4	2.155	2.298	0.061
2 1/2	2.5000	3 7/8	3.750	3.875	4.275	4.474	2 1/2	2.401	2.552	0.067
2 3/4	2.7500	4 1/4	4.112	4.250	4.688	4.907	2 3/4	2.647	2.806	0.074
3	3.0000	4 5/8	4.475	4.625	5.102	5.340	3	2.893	3.060	0.080
3 1/4	3.2500	5	4.838	5.000	5.515	5.774	3 1/4	3.124	3.314	0.087
3 1/2	3.5000	5 3/8	5.200	5.375	5.928	6.207	3 1/2	3.370	3.568	0.093
3 3/4	3.7500	5 3/4	5.562	5.750	6.341	6.640	3 3/4	3.616	3.822	0.100
4	4.0000	6 1/8	5.925	6.125	6.755	7.073	4	3.862	4.076	1.06
All dimensions are in inches. Bold type indicates nuts unified dimensionally with British and Canadian Standards. Threads are Unified Coarse-thread series (UNC), Class 2B.