ASME B18.2.2 Heavy Hex Flat Jam Nuts

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

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness, H1			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	15.875	14.707	16.637	0.813
1 1/4	31.750	50.800	49.225	50.800	56.109	58.649	19.050	17.450	19.863	0.864
1 3/8	34.925	55.563	53.823	55.575	61.366	64.160	20.638	18.974	21.488	0.965
1 1/2	38.100	60.325	58.420	60.325	66.599	69.647	22.225	20.523	23.139	1.041
1 3/4	44.450	69.850	67.615	69.850	77.089	80.645	25.400	23.597	26.416	1.219
2	50.800	79.375	76.835	79.375	87.605	91.643	28.575	26.670	29.693	1.372
2 1/4	57.150	88.900	86.055	88.900	98.095	102.641	31.750	29.337	32.969	1.549
2 1/2	63.500	98.425	95.250	98.425	108.585	113.640	38.100	35.585	39.421	1.702
2 3/4	69.850	107.950	104.445	107.950	119.075	124.638	41.275	38.659	42.697	1.880
3	76.200	117.475	113.665	117.475	129.591	135.636	44.450	41.732	45.974	2.032
3 1/4	82.550	127.000	122.885	127.000	140.081	146.660	47.625	44.399	49.251	2.210
3 1/2	88.900	136.525	132.080	136.525	150.571	157.658	50.800	47.498	52.527	2.362
3 3/4	95.250	146.050	141.275	146.050	161.061	168.656	53.975	50.546	55.804	2.540
4	101.600	155.575	150.495	155.575	171.577	179.654	57.150	53.645	59.080	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 Jam Nuts Dimensions (Inch)

Nominal Size	Basic Major Diameter of Thread	Width Across Flats, F			Width Across Corners, G		Thickness, H1			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	5/8	0.579	0.655	0.032
1 1/4	1.2500	2	1.938	2.000	2.209	2.309	3/4	0.687	0.782	0.034
1 3/8	1.3750	2 3/16	2.119	2.188	2.416	2.526	13/16	0.747	0.846	0.038
1 1/2	1.5000	2 3/8	2.300	2.375	2.622	2.742	7/8	0.808	0.911	0.041
1 3/4	1.7500	2 3/4	2.662	2.750	3.035	3.175	1	0.929	1.040	0.048
2	2.0000	3 1/8	3.025	3.125	3.449	3.608	1 1/8	1.050	1.169	0.054
2 1/4	2.2500	3 1/2	3.388	3.500	3.862	4.041	1 1/4	1.155	1.298	0.061
2 1/2	2.5000	3 7/8	3.750	3.875	4.275	4.474	1 1/2	1.401	1.552	0.067
2 3/4	2.7500	4 1/4	4.112	4.250	4.688	4.907	1 5/8	1.522	1.681	0.074
3	3.0000	4 5/8	4.475	4.625	5.102	5.340	1 3/4	1.643	1.810	0.080
3 1/4	3.2500	5	4.838	5.000	5.515	5.774	1 7/8	1.748	1.939	0.087
3 1/2	3.5000	5 3/8	5.200	5.375	5.928	6.207	2	1.870	2.068	0.093
3 3/4	3.7500	5 3/4	5.562	5.750	6.341	6.640	2 1/8	1.990	2.197	0.100
4	4.0000	6 1/8	5.925	6.125	6.755	7.073	2 1/4	2.112	2.326	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.