ASME B18.2.2 Heavy Hex Flat Nuts

ASME B18.2.2 Heavy Hex Flat Nuts Standard covers the dimensional requirements for nine product types of inch series bolts and screws recognized as American National Standard. Also included are appendices covering gaging procedures, grade markings for bolts and screws, formulas on which dimensional data are based, and a specification to assist in identifying a product as being a screw or a bolt. Where questions arise concerning acceptance of product, the dimensions in the tables shall govern over recalculation by formula. Heavy hex structural bolts, formerly covered in ASME B18.2.1, are now covered in ASME B18.2.6.
The inclusion of dimensional data in this Standard is not intended to imply that all of the products described herein are stock production sizes. Consumers should consult with suppliers concerning lists of stock production sizes.

ASME B18.2.2 Heavy Hex Flat Nuts Dimensions (mm)

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness, H			Bearing Surface Runout to Thread Axis, FIM
		Basic	Min.	Max.	Min.	Max.	Basic	Min.	Max.
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.

ASME B18.2.2 Heavy Hex Flat Nuts Dimensions (Inch)

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness, H			Bearing Surface Runout to Thread Axis, FIM
		Basic	Min.	Max.	Min.	Max.	Basic	Min.	Max.
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.