ASME B18.2.2 Square Nuts

ASME B18.2.2 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 Square Nuts Dimensions (mm)

Nominal Size (in)	Basic Major Diameter	Width Across Flats, F			Width Across Corners, G		Thickness			Runout to Thread Axis, FIM
		Basic	Min.	Max.	Min.	Max.	Basic	Min.	Max.
1/4	6.350	11.11	10.80	11.13	14.07	15.72	5.56	5.16	5.97	0.28
5/16	7.938	14.29	13.89	14.27	18.31	20.19	6.75	6.32	7.19	0.38
3/8	9.525	15.88	15.39	15.88	20.37	22.45	8.33	7.87	8.79	0.41
7/16	11.113	19.05	18.49	19.05	24.64	26.95	9.53	9.04	10.01	0.48
1/2	12.700	20.64	20.02	20.62	26.72	29.18	11.11	10.62	11.63	0.56
5/8	15.875	25.40	24.61	25.40	33.02	35.92	13.89	13.34	14.45	0.66
3/4	19.050	28.58	27.64	28.58	37.19	40.41	16.67	16.05	17.27	0.74
7/8	22.225	33.34	32.23	33.32	43.48	47.14	19.45	18.80	20.12	0.86
1	25.400	38.10	36.83	38.10	49.81	53.87	22.23	21.51	22.94	0.99
1 1/8	28.575	42.86	41.43	42.88	56.11	60.60	25.40	24.64	26.16	0.74
1 1/4	31.750	47.63	46.02	47.63	62.43	67.36	27.78	26.97	28.60	0.81
1 3/8	34.925	52.39	50.65	52.37	68.78	74.09	30.56	29.69	31.42	0.89
1 1/2	38.100	57.15	55.25	57.15	75.08	80.82	33.34	32.41	34.24	0.99

ASME B18.2.2 Square Nuts Dimensions (Inch)

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness			Bearing Surface Runout to Thread Axis, FIM
		Basic	Min.	Max.	Min.	Max.	Basic	Min.	Max.
1/4	0.2500	7/16	0.425	0.438	0.554	0.619	7/32	0.203	0.235	0.011
5/16	0.3125	9/16	0.547	0.562	0.721	0.795	17/64	0.249	0.283	0.015
3/8	0.3750	5/8	0.606	0.625	0.802	0.884	21/64	0.310	0.346	0.016
7/16	0.4375	3/4	0.728	0.750	0.970	1.061	3/8	0.356	0.394	0.019
1/2	0.5000	13/16	0.788	0.812	1.052	1.149	7/16	0.418	0.458	0.022
5/8	0.6250	1	0.969	1.000	1.300	1.414	35/64	0.525	0.569	0.026
3/4	0.7500	1 1/8	1.088	1.125	1.464	1.591	21/32	0.632	0.680	0.029
7/8	0.8750	1 5/16	1.269	1.312	1.712	1.856	49/64	0.740	0.792	0.034
1	1.0000	1 1/2	1.450	1.500	1.961	2.121	7/8	0.847	0.903	0.039
1 1/8	1.1250	1 11/16	1.631	1.688	2.209	2.386	1	0.970	1.030	0.029
1 1/4	1.2500	1 7/8	1.812	1.875	2.458	2.652	1 3/32	1.062	1.126	0.032
1 3/8	1.3750	2 1/16	1.994	2.062	2.708	2.917	1 13/64	1.169	1.237	0.035
1 1/2	1.5000	2 1/4	2.175	2.250	2.956	3.182	1 5/16	1.276	1.348	0.039