ASME B18.2.2 Heavy Square Nuts

ASME B18.2.2 Heavy Square 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 Square 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.
1/4	6.350	12.700	12.395	12.700	16.256	17.958	6.350	5.537	6.756	0.660
5/16	7.938	14.288	13.868	14.275	18.288	20.193	7.938	7.112	8.382	0.762
3/8	9.525	17.463	16.993	17.475	22.581	24.714	9.525	8.661	9.982	0.914
7/16	11.113	19.050	18.491	19.050	24.638	26.924	11.113	10.236	11.582	0.991
1/2	12.700	22.225	21.590	22.225	28.880	31.420	12.700	11.786	13.208	1.168
5/8	15.875	26.988	26.187	26.975	35.204	38.176	15.875	14.910	16.434	1.422
3/4	19.050	31.750	30.785	31.750	41.529	44.907	19.050	18.034	19.660	1.651
7/8	22.225	36.513	35.408	36.525	47.854	51.638	22.225	21.158	22.885	1.905
1	25.400	41.275	40.005	41.275	54.153	58.369	25.400	24.282	26.111	2.083
1 1/8	28.575	46.038	44.602	46.025	60.477	65.100	28.575	27.407	29.337	1.600
1 1/4	31.750	50.800	49.225	50.800	66.827	71.831	31.750	30.150	32.563	1.778
1 3/8	34.925	55.563	53.823	55.575	73.127	78.588	34.925	33.274	35.789	1.930
1 1/2	38.100	60.325	58.420	60.325	79.451	85.319	38.100	36.398	39.014	2.083

ASME B18.2.2 Heavy Square 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.
1/4	0.2500	1/2	0.488	0.500	0.640	0.707	1/4	0.218	0.266	0.026
5/16	0.3125	9/16	0.546	0.562	0.720	0.795	5/16	0.280	0.330	0.030
3/8	0.3750	11/16	0.669	0.688	0.889	0.973	3/8	0.341	0.393	0.036
7/16	0.4375	3/4	0.728	0.750	0.970	1.060	7/16	0.403	0.456	0.039
1/2	0.5000	7/8	0.850	0.875	1.137	1.237	1/2	0.464	0.520	0.046
5/8	0.6250	1 1/16	1.031	1.062	1.386	1.503	5/8	0.587	0.647	0.056
3/4	0.7500	1 1/4	1.212	1.250	1.635	1.768	3/4	0.710	0.774	0.065
7/8	0.8750	1 7/16	1.394	1.438	1.884	2.033	7/8	0.833	0.901	0.075
1	1.0000	1 5/8	1.575	1.625	2.132	2.298	1	0.956	1.028	0.082
1 1/8	1.1250	1 13/16	1.756	1.812	2.381	2.563	1 1/8	1.079	1.155	0.063
1 1/4	1.2500	2	1.938	2.000	2.631	2.828	1 1/4	1.187	1.282	0.070
1 3/8	1.3750	2 3/16	2.119	2.188	2.879	3.094	1 3/8	1.310	1.409	0.076
1 1/2	1.5000	2 3/8	2.300	2.375	3.128	3.359	1 1/2	1.433	1.536	0.082