ASME B18.2.1 Hex Screws

Scope

ASME B18.2.1 Hex Screws dimension standard covers the dimensional requirements for product types of 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 Tables measurements are also converted into millimeters to make the information clearer and easier to to understand.

ASME B18.2.1 Hex Screws Dimensions (mm)

Nominal Size (Inch)		Body Diameter, E		Width Across Flats, F			Width Across Corners, G		Head Height, H			Minimum Wrenching Height, J	Nominal Thread Length for Screw Lengths, LT		Transition Thread Length, Y (Reference, mm)	Maximum Total Runout of Bearing Surface FIM (mm)
Frac.	Dec.	Max.	Min.	Basic	Max.	Min.	Max.	Min.	Basic	Max.	Min.	Minimum Wrenching Height, J	6 in. and Shorter	Over 6 in.	Transition Thread Length, Y (Reference, mm)	Maximum Total Runout of Bearing Surface FIM (mm)
3/8	0.3750	9.525	9.144	17.463	17.475	16.993	20.168	19.380	5.953	6.172	5.740	4.064	25.400	31.750	7.925	0.356
1/2	0.5000	12.700	12.243	22.225	22.225	21.590	25.654	24.613	7.938	8.204	7.671	5.461	31.750	38.100	9.779	0.406
5/8	0.6250	15.875	15.367	26.988	26.975	26.187	31.166	29.845	9.922	10.236	9.601	6.833	38.100	44.450	11.557	0.483
3/4	0.7500	19.050	18.517	31.750	31.750	30.785	36.652	35.128	11.906	12.268	11.557	8.230	44.450	50.800	12.700	0.559
7/8	0.8750	22.225	21.641	36.513	36.525	35.408	42.164	40.361	13.891	14.300	13.487	9.601	50.800	57.150	14.122	0.635
1	1.0000	25.400	24.790	41.275	41.275	40.005	47.650	45.618	15.478	15.926	15.011	10.566	57.150	63.500	15.875	0.711
1 1/8	1.1250	28.575	27.889	46.038	46.025	44.602	53.162	50.851	17.463	18.237	16.713	11.709	63.500	69.850	18.136	0.813
1 1/4	1.2500	31.750	31.064	50.800	50.800	49.225	58.649	56.109	19.844	20.650	19.025	13.462	69.850	76.200	18.136	0.889
1 3/8	1.3750	34.925	34.163	55.563	55.575	53.823	64.160	61.366	21.431	22.301	20.574	14.453	76.200	82.550	21.158	0.965
1 1/2	1.5000	38.100	37.338	60.325	60.325	58.420	69.647	66.599	23.813	24.740	22.911	16.256	82.550	88.900	21.158	1.041
1 5/8	1.6250	41.275	40.411	65.088	65.075	63.017	75.159	71.857	25.400	26.365	24.435	17.628	88.900	95.250	23.089	1.118
1 3/4	1.7500	44.450	43.586	69.850	69.850	67.615	80.645	77.089	27.781	28.804	26.772	18.999	95.250	101.600	25.400	1.219
1 7/8	1.8750	47.625	46.711	74.613	74.625	72.238	86.157	82.347	29.369	30.429	28.296	20.371	101.600	107.950	25.400	1.321
2	2.0000	50.800	49.886	79.375	79.375	76.835	91.643	87.605	30.956	32.080	29.845	20.955	107.950	114.300	28.219	1.397
2 1/4	2.2500	57.150	56.236	88.900	88.900	86.055	102.641	98.095	34.925	36.144	33.706	23.698	...	127.000	28.219	1.549
2 1/2	2.5000	63.500	62.509	98.425	98.425	95.250	113.640	108.585	38.894	40.208	37.567	26.467	...	139.700	31.750	1.727
2 3/4	2.7500	69.850	68.859	107.950	107.950	104.445	124.638	119.075	42.863	44.298	41.453	29.235	...	152.400	31.750	1.880
3	3.0000	76.200	75.209	117.475	117.475	113.665	135.636	129.591	47.625	49.149	46.101	32.766	...	165.100	31.750	2.057
3 1/4	3.2500	82.550	81.534	127.000	127.000	122.885	146.660	140.081	50.800	54.000	50.749	35.535	...	177.800	31.750	2.311
3 1/2	3.5000	88.900	87.909	136.525	136.525	132.080	157.658	150.571	57.150	57.302	53.848	37.694	...	190.500	31.750	2.489
3 3/4	3.7500	95.250	94.257	146.050	146.050	141.275	168.656	161.061	60.325	62.154	58.496	40.945	...	203.200	31.750	2.667
4	4.0000	101.600	100.607	155.575	155.575	150.495	179.654	171.577	63.500	65.430	61.570	43.104	...	215.900	31.750	2.845
4 1/4	4.2500	107.950	107.259	165.100	165.100	159.715	190.652	182.067	69.850	70.307	66.243	46.380	...	228.600	31.750	3.023
4 1/2	4.5000	114.300	113.607	174.625	174.625	168.910	201.651	192.557	73.025	73.558	69.291	48.514	...	241.300	31.750	3.200
4 3/4	4.7500	120.650	119.957	184.150	184.150	178.105	212.649	203.048	76.200	78.435	73.965	51.765	...	254.000	31.750	3.378
5	5.0000	127.000	126.304	193.675	193.675	187.325	223.647	213.563	79.375	81.712	77.038	53.924	...	266.700	31.750	3.556
5 1/4	5.2500	133.350	132.654	203.200	203.200	196.545	234.645	224.053	85.725	86.563	81.686	57.175	...	279.400	31.750	3.734
5 1/2	5.5000	139.700	139.004	212.725	212.725	205.740	245.643	234.544	88.900	89.865	84.785	59.360	...	292.100	31.750	3.912
5 3/4	5.7500	146.050	145.352	222.250	222.250	214.935	256.642	245.034	92.075	94.717	89.433	62.611	...	304.800	31.750	4.089
6	6.0000	152.400	151.702	231.775	231.775	224.155	267.640	255.524	95.250	97.993	92.507	64.745	...	317.500	31.750	4.267

ASME B18.2.1 Hex Screws Length Tolerance (mm)

Nominal Length	Nominal Size (inches)
Nominal Length	1/4 to 3/8	7/16 and 1/2	9/16 to 3/4	7/8 and 1	1 1/8 to 1 1/2	Over 1 1/2
Up to 25.4 mm, incl.	+0.000 0.762	+0.000 0.762	+0.000 0.762	...	...	...
Over 25.4 mm to 63.5 mm, incl.	+0.000 1.016	+0.000 1.524	+0.000 2.032	+0.000 2.540	+0.000 3.048	+0.000 4.572
Over 63.5 mm to 101.6 mm, incl.	+0.000 1.524	+0.000 2.032	+0.000 2.540	+0.000 3.556	+0.000 4.064	+0.000 5.080
Over 101.6 mm to 152.4 mm, incl.	+0.000 2.540	+0.000 2.540	+0.000 2.540	+0.000 4.064	+0.000 4.572	+0.000 5.588
Longer than 152.4 mm	+0.000 4.572	+0.000 4.572	+0.000 4.572	+0.000 5.080	+0.000 5.588	+0.000 6.096

ASME B18.2.1 Hex Screws Grip Gaging Lengths (mm)

Nominal Size	Nominal Length, Lg, max. / Lb, min.
	1-1/4		1-3/8		1-1/2		1-5/8		1-3/4		1-7/8		2		2-1/8		2-1/4		2-3/8		2-1/2		2-5/8		2-3/4		2-7/8		3		3-1/4		3-1/2		3-3/4		4		4-1/4		4-1/2		4-3/4		5		5-1/4		5-1/2		5-3/4		6		6-1/4		6-1/2		6-3/4		7		7-1/4		7-1/2		7-3/4		8		8-1/4		8-1/2		8-3/4		9		9-1/4		9-1/2		9-3/4		10		11		12
	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.
1/4	0.50	0.25	0.63	0.38	0.75	0.50	0.88	0.62	1.00	0.75	1.12	0.88	1.25	1.00	1.38	1.12	1.50	1.25	1.62	1.38	1.75	1.50	1.88	1.62	2.00	1.75	2.12	1.88	2.52	2.00	2.50	2.25	2.75	2.50	3.00	2.75	3.25	3.00	3.50	3.25	3.75	3.50	4.00	3.75	4.25	4.00	4.50	4.25	4.75	4.50	5.00	4.75	5.25	5.00	5.25	5.00	5.50	5.25	5.75	5.50	6.00	5.75	6.25	6.00	6.50	6.25	6.75	6.50	7.00	6.75	7.25	7.00	7.50	7.25	7.75	7.50	8.00	7.75	8.25	8.00	8.50	8.25	8.75	8.50	9.00	8.75	10.00	9.75	11.00	10.75
5/16	Full thread		0.50	0.22	0.62	0.35	0.75	0.47	0.88	0.60	1.00	0.72	1.12	0.85	1.25	0.97	1.38	1.10	1.50	1.22	1.62	1.35	1.75	1.47	1.88	1.60	2.00	1.72	2.12	1.85	2.38	2.10	2.62	2.35	2.88	2.60	3.12	2.85	3.38	3.10	3.62	3.35	3.88	3.60	4.12	3.85	4.38	4.10	4.62	4.35	4.88	4.60	5.12	4.85	5.12	4.85	5.38	5.10	5.62	5.35	5.88	5.60	6.12	5.85	6.38	6.10	6.62	6.35	6.88	6.60	7.12	6.85	7.38	7.10	7.62	7.35	7.88	7.60	8.12	7.85	8.38	8.10	8.62	8.35	8.88	8.60	9.88	9.60	10.88	10.60
3/8	Full thread		Full thread		0.50	0.19	0.62	0.31	0.75	0.44	0.88	0.56	1.00	0.69	1.12	0.81	1.25	0.94	1.38	1.06	1.50	1.19	1.62	1.31	1.75	1.44	1.88	1.56	2.00	1.69	2.25	1.94	2.50	2.19	2.75	2.44	3.00	2.69	3.25	2.94	3.50	3.19	3.75	3.44	4.00	3.69	4.25	3.94	4.50	4.19	4.75	4.44	5.00	4.69	5.00	4.69	5.25	4.94	5.50	5.19	5.75	5.44	6.00	5.69	6.25	5.94	6.50	6.19	6.75	6.44	7.00	6.69	7.25	6.94	7.50	7.19	7.75	7.44	8.00	7.69	8.25	7.94	8.50	8.19	8.75	8.44	9.75	9.44	10.75	10.44
7/16	Full thread		Full thread		Full thread		Full thread		0.63	0.27	0.75	0.39	0.88	0.52	1.00	0.64	1.12	0.77	1.25	0.89	1.38	1.02	1.50	1.14	1.62	1.27	1.75	1.39	1.88	1.52	2.12	1.77	2.38	2.02	2.62	2.27	2.88	2.52	3.12	2.77	3.38	3.02	3.62	3.27	3.88	3.52	4.12	3.77	4.38	4.02	4.63	4.27	4.88	4.52	4.88	4.52	5.12	4.77	5.38	5.02	5.62	5.27	5.88	5.52	6.12	5.77	6.38	6.02	6.62	6.27	6.88	6.52	7.12	6.77	7.38	7.02	7.62	7.27	7.88	7.52	8.12	7.77	8.38	8.02	8.62	8.27	9.62	9.27	10.62	10.27
1/2	Full thread		Full thread		Full thread		Full thread		Full thread		0.63	0.24	0.75	0.38	0.88	0.49	1.00	0.62	1.12	0.74	1.25	0.86	1.38	0.99	1.50	1.12	1.62	1.24	1.75	1.36	2.00	1.62	2.25	1.86	2.50	2.12	2.75	2.36	3.00	2.62	3.25	2.86	3.50	3.12	3.75	3.36	4.00	3.62	4.25	3.87	4.50	4.12	4.75	4.36	4.75	4.36	5.00	4.62	5.25	4.86	5.50	5.12	5.75	5.36	6.00	5.62	6.25	5.87	6.50	6.12	6.75	6.36	7.00	6.62	7.25	6.86	7.50	7.12	7.75	7.36	8.00	7.62	8.25	7.86	8.50	8.12	9.50	9.12	10.50	10.12
9/16	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		0.75	0.33	0.88	0.45	1.00	0.58	1.12	0.75	1.25	0.83	1.38	0.96	1.50	1.08	1.62	1.21	1.88	1.46	2.12	1.71	2.38	1.96	2.62	2.21	2.88	2.46	3.12	2.71	3.38	2.96	3.62	3.21	3.88	3.46	4.12	3.71	4.38	3.96	4.62	4.21	4.62	4.21	4.88	4.46	5.12	4.71	5.38	4.96	5.62	5.20	5.88	5.46	6.12	5.71	6.38	5.96	6.62	6.21	6.88	6.46	7.12	6.71	7.38	6.96	7.62	7.21	7.88	7.46	8.12	7.71	8.38	7.96	9.38	8.96	10.38	9.96
5/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		0.75	0.30	0.88	0.42	1.00	0.55	1.12	0.67	1.25	0.80	1.38	0.92	1.50	1.05	1.75	1.30	2.00	1.55	2.25	1.80	2.50	2.05	2.75	2.30	3.00	2.55	3.25	2.80	3.50	3.05	3.75	3.30	4.00	3.55	4.25	3.80	4.50	4.05	4.50	4.05	4.75	4.30	5.00	4.55	5.25	4.80	5.50	5.05	5.75	5.30	6.00	5.55	6.25	5.80	6.50	6.05	6.75	6.30	7.00	6.55	7.25	6.80	7.50	7.05	7.75	7.30	8.00	7.55	8.25	7.80	9.25	8.80	10.25	9.80
3/4	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		1.12	0.67	1.25	0.80	1.38	0.92	1.50	1.05	1.50	1.00	1.75	1.25	2.00	1.50	2.25	1.75	2.50	2.00	2.75	2.25	3.00	2.50	3.25	2.75	3.50	3.00	3.75	3.25	4.00	3.50	4.25	3.75	4.25	3.75	4.50	4.00	4.75	4.25	5.00	4.50	5.25	4.75	5.50	5.00	5.75	5.25	6.00	5.50	6.25	5.75	6.50	6.00	6.75	6.25	7.00	6.50	7.25	6.75	7.50	7.00	7.75	7.25	8.00	7.50	9.00	8.50	10.00	9.50
7/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		1.00	0.50	1.12	0.62	1.25	0.75	1.25	0.69	1.50	0.94	1.75	1.19	2.00	1.44	2.25	1.69	2.50	1.94	2.75	2.19	3.00	2.44	3.25	2.69	3.50	2.94	3.75	3.19	4.00	3.44	4.00	3.44	4.25	3.69	4.50	3.94	4.75	4.19	5.00	4.44	5.25	4.69	5.50	4.94	5.75	5.19	6.00	5.44	6.25	5.69	6.50	5.94	6.75	6.19	7.00	6.44	7.25	6.89	7.50	6.94	7.75	7.19	8.75	8.19	9.75	9.19
1	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		0.88	0.32	1.00	0.44	1.00	0.38	1.25	0.62	1.50	0.88	1.75	1.12	2.00	1.38	2.25	1.62	2.50	1.88	2.75	2.12	3.00	2.38	3.25	2.62	3.50	2.88	3.75	3.12	3.75	3.12	4.00	3.38	4.25	3.63	4.50	3.88	4.75	4.12	5.00	4.38	5.25	4.52	5.50	4.88	5.75	5.12	6.00	5.38	6.25	5.62	6.50	5.88	6.75	6.12	7.00	6.38	7.25	6.62	7.50	6.88	8.50	7.88	9.50	8.88
1-1/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		1.25	0.54	1.50	0.79	1.75	1.04	2.00	1.29	2.25	1.54	2.50	1.79	2.75	2.04	3.00	2.29	3.25	2.54	3.50	2.79	3.50	2.79	3.75	3.04	4.00	3.29	4.25	3.54	4.50	3.79	4.75	4.04	5.00	4.29	5.25	4.54	5.50	4.79	5.75	5.04	6.00	5.29	6.25	5.54	6.50	5.79	6.75	6.04	7.00	6.29	7.25	6.54	8.25	7.54	9.25	8.54
1-1/4	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		1.25	0.54	1.50	0.79	1.75	1.04	2.00	1.29	2.25	1.54	2.50	1.79	2.75	2.04	3.00	2.29	3.25	2.54	3.25	2.54	3.50	2.79	3.75	3.04	4.00	3.29	4.25	3.54	4.50	3.79	4.75	4.04	5.00	4.29	5.25	4.54	5.50	4.79	5.75	5.04	6.00	5.29	6.25	5.54	6.50	5.79	6.75	6.04	7.00	6.29	8.00	7.29	9.00	8.29
1-3/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		1.50	0.79	1.75	1.04	2.00	1.29	2.25	1.54	2.50	1.79	2.75	2.04	3.00	2.29	3.25	2.54	3.25	2.54	3.50	2.79	3.75	3.04	4.00	3.29	4.25	3.54	4.50	3.79	4.75	4.04	5.00	4.29	5.25	4.54	5.50	4.79	5.75	5.04	6.00	5.29	6.25	5.54	6.50	5.79	6.75	6.04	7.75	7.04	8.75	8.04
1-1/2	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		1.50	0.67	1.75	0.92	2.00	1.17	2.25	1.42	2.50	1.67	2.75	1.92	2.75	1.92	3.00	2.17	3.25	2.42	3.50	2.67	3.75	2.92	4.00	3.17	4.25	3.42	4.50	3.67	4.75	3.92	5.00	4.17	5.25	4.42	5.50	4.67	5.75	4.92	6.00	5.17	6.25	5.42	6.50	5.67	7.50	6.67	8.50	7.67

ASME B18.2.1 Hex Screws Dimensions (Inch)

Nominal Size		Body Diameter, E		Width Across Flats, F			Width Across Corners, G		Head Height, H			Minimum Wrenching Height, J	Nominal Thread Length for Screw Lengths, LT		Transition Thread Length, Y	Maximum Total Runout of Bearing Surface FIM
Frac.	Dec.	Max.	Min.	Basic	Max.	Min.	Max.	Min.	Basic	Max.	Min.	Minimum Wrenching Height, J	6 in. and Shorter	Over 6 in.	Transition Thread Length, Y	Maximum Total Runout of Bearing Surface FIM
3/8	0.3750	0.3750	0.360	11/16	0.688	0.669	0.794	0.763	15/64	0.243	0.226	0.160	1.000	1.250	0.312	0.014
1/2	0.5000	0.5000	0.482	7/8	0.875	0.850	1.010	0.969	5/16	0.323	0.302	0.215	1.250	1.500	0.385	0.016
5/8	0.6250	0.6250	0.605	1 1/16	1.062	1.031	1.227	1.175	25/64	0.403	0.378	0.269	1.500	1.750	0.455	0.019
3/4	0.7500	0.7500	0.729	1 1/4	1.250	1.212	1.443	1.383	15/32	0.483	0.455	0.324	1.750	2.000	0.500	0.022
7/8	0.8750	0.8750	0.852	1 7/16	1.438	1.394	1.660	1.589	35/64	0.563	0.531	0.378	2.000	2.250	0.556	0.025
1	1.0000	1.0000	0.976	1 5/8	1.625	1.575	1.876	1.796	39/64	0.627	0.591	0.416	2.250	2.500	0.625	0.028
1 1/8	1.1250	1.1250	1.098	1 13/16	1.812	1.756	2.093	2.002	11/16	0.718	0.658	0.461	2.500	2.750	0.714	0.032
1 1/4	1.2500	1.2500	1.223	2	2.000	1.938	2.309	2.209	25/32	0.813	0.749	0.530	2.750	3.000	0.714	0.035
1 3/8	1.3750	1.3750	1.345	2 3/16	2.188	2.119	2.526	2.416	27/32	0.878	0.810	0.569	3.000	3.250	0.833	0.038
1 1/2	1.5000	1.5000	1.470	2 3/8	2.375	2.300	2.742	2.622	15/16	0.974	0.902	0.640	3.250	3.500	0.833	0.041
1 5/8	1.6250	1.6250	1.591	2 9/16	2.562	2.481	2.959	2.829	1	1.038	0.962	0.694	3.500	3.750	0.909	0.044
1 3/4	1.7500	1.7500	1.716	2 3/4	2.750	2.662	3.175	3.035	1 3/32	1.134	1.054	0.748	3.750	4.000	1.000	0.048
1 7/8	1.8750	1.8750	1.839	2 15/16	2.938	2.844	3.392	3.242	1 5/32	1.198	1.114	0.802	4.000	4.250	1.000	0.052
2	2.0000	2.0000	1.964	3 1/8	3.125	3.025	3.608	3.449	1 7/32	1.263	1.175	0.825	4.250	4.500	1.111	0.055
2 1/4	2.2500	2.2500	2.214	3 1/2	3.500	3.388	4.041	3.862	1 3/8	1.423	1.327	0.933	...	5.000	1.111	0.061
2 1/2	2.5000	2.5000	2.4610	3 7/8	3.8750	3.750	4.474	4.275	1 17/32	1.583	1.479	1.042	...	5.500	1.250	0.068
2 3/4	2.7500	2.7500	2.7110	4 1/4	4.2500	4.112	4.907	4.688	1 11/16	1.744	1.632	1.151	...	6.000	1.250	0.074
3	3.0000	3.0000	2.9610	4 5/8	4.6250	4.475	5.340	5.102	1 7/8	1.935	1.815	1.290	...	6.500	1.250	0.081
3 1/4	3.2500	3.2500	3.2100	5	5.0000	4.838	5.774	5.515	2	2.126	1.998	1.399	...	7.000	1.250	0.091
3 1/2	3.5000	3.5000	3.4610	5 3/8	5.3750	5.200	6.207	5.928	2 1/4	2.256	2.120	1.484	...	7.500	1.250	0.098
3 3/4	3.7500	3.7500	3.7109	5 3/4	5.7500	5.562	6.640	6.341	2 3/8	2.447	2.303	1.612	...	8.000	1.250	0.105
4	4.0000	4.0000	3.9609	6 1/8	6.1250	5.925	7.073	6.755	2 1/2	2.576	2.424	1.697	...	8.500	1.250	0.112
4 1/4	4.2500	4.2500	4.2228	6 1/2	6.5000	6.288	7.506	7.168	2 3/4	2.768	2.608	1.826	...	9.000	1.250	0.119
4 1/2	4.5000	4.5000	4.4727	6 7/8	6.8750	6.650	7.939	7.581	2 7/8	2.896	2.728	1.910	...	9.500	1.250	0.126
4 3/4	4.7500	4.7500	4.7227	7 1/4	7.2500	7.012	8.372	7.994	3	3.088	2.912	2.038	...	10.000	1.250	0.133
5	5.0000	5.0000	4.9726	7 5/8	7.6250	7.375	8.805	8.408	3 1/8	3.217	3.033	2.123	...	10.500	1.250	0.140
5 1/4	5.2500	5.2500	5.2226	8	8.0000	7.738	9.238	8.821	3 3/8	3.408	3.216	2.251	...	11.000	1.250	0.147
5 1/2	5.5000	5.5000	5.4726	8 3/8	8.3750	8.100	9.671	9.234	3 1/2	3.538	3.338	2.337	...	11.500	1.250	0.154
5 3/4	5.7500	5.7500	5.7225	8 3/4	8.7500	8.462	10.104	9.647	3 5/8	3.729	3.521	2.465	...	12.000	1.250	0.161
6	6.0000	6.0000	5.9725	9 1/8	9.1250	8.825	10.537	10.060	3 3/4	3.858	3.642	2.549	...	12.500	1.250	0.168

ASME B18.2.1 Hex Screws Length Tolerance (Inch)

Nominal Length	Nominal Size
Nominal Length	1/4 to 3/8	7/16 and 1/2	9/16 to 3/4	7/8 and 1	1 1/8 to 1 1/2	Over 1 1/2
Up to 1 in., incl.	+0.00 0.03	+0.00 0.03	+0.00 0.03	...	...	...
Over 1 in. to 2 1/2 in., incl.	+0.00 0.04	+0.00 0.06	+0.00 0.08	+0.00 0.10	+0.00 0.12	+0.00 0.18
Over 2 1/2 in. to 4 in., incl.	+0.00 0.06	+0.00 0.08	+0.00 0.10	+0.00 0.14	+0.00 0.16	+0.00 0.20
Over 4 in. to 6 in., incl.	+0.00 0.10	+0.00 0.10	+0.00 0.10	+0.00 0.16	+0.00 0.18	+0.00 0.22
Longer than 6 in.	+0.00 0.18	+0.00 0.18	+0.00 0.18	+0.00 0.20	+0.00 0.22	+0.00 0.24

ASME B18.2.1 Hex Screws Grip Gaging Lengths (Inch)

Nominal Size	Nominal Length, Lg, max. / Lb, min.
	1-1/4		1-3/8		1-1/2		1-5/8		1-3/4		1-7/8		2		2-1/8		2-1/4		2-3/8		2-1/2		2-5/8		2-3/4		2-7/8		3		3-1/4		3-1/2		3-3/4		4		4-1/4		4-1/2		4-3/4		5		5-1/4		5-1/2		5-3/4		6		6-1/4		6-1/2		6-3/4		7		7-1/4		7-1/2		7-3/4		8		8-1/4		8-1/2		8-3/4		9		9-1/4		9-1/2		9-3/4		10		11		12
	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.	L_g Max.	L_b Min.
1/4	12.70	6.35	16.00	9.65	19.05	12.70	22.35	15.75	25.40	19.05	28.45	22.35	31.75	25.40	35.05	28.45	38.10	31.75	41.15	35.05	44.45	38.10	47.75	41.15	50.80	44.45	53.85	47.75	64.01	50.80	63.50	57.15	69.85	63.50	76.20	69.85	82.55	76.20	88.90	82.55	95.25	88.90	101.60	95.25	107.95	101.60	114.30	107.95	120.65	114.30	127.00	120.65	133.35	127.00	133.35	127.00	139.70	133.35	146.05	139.70	152.40	146.05	158.75	152.40	165.10	158.75	171.45	165.10	177.80	171.45	184.15	177.80	190.50	184.15	196.85	190.50	203.20	196.85	209.55	203.20	215.90	209.55	222.25	215.90	228.60	222.25	254.00	247.65	279.40	273.05
5/16	Full thread		12.70	5.59	15.75	8.89	19.05	11.94	22.35	15.24	25.40	18.29	28.45	21.59	31.75	24.64	35.05	27.94	38.10	30.99	41.15	34.29	44.45	37.34	47.75	40.64	50.80	43.69	53.85	46.99	60.45	53.34	66.55	59.69	73.15	66.04	79.25	72.39	85.85	78.74	91.95	85.09	98.55	91.44	104.65	97.79	111.25	104.14	117.35	110.49	123.95	116.84	130.05	123.19	130.05	123.19	136.65	129.54	142.75	135.89	149.35	142.24	155.45	148.59	162.05	154.94	168.15	161.29	174.75	167.64	180.85	173.99	187.45	180.34	193.55	186.69	200.15	193.04	206.25	199.39	212.85	205.74	218.95	212.09	225.55	218.44	250.95	243.84	276.35	269.24
3/8	Full thread		Full thread		12.70	4.83	15.75	7.87	19.05	11.18	22.35	14.22	25.40	17.53	28.45	20.57	31.75	23.88	35.05	26.92	38.10	30.23	41.15	33.27	44.45	36.58	47.75	39.62	50.80	42.93	57.15	49.28	63.50	55.63	69.85	61.98	76.20	68.33	82.55	74.68	88.90	81.03	95.25	87.38	101.60	93.73	107.95	100.08	114.30	106.43	120.65	112.78	127.00	119.13	127.00	119.13	133.35	125.48	139.70	131.83	146.05	138.18	152.40	144.53	158.75	150.88	165.10	157.23	171.45	163.58	177.80	169.93	184.15	176.28	190.50	182.63	196.85	188.98	203.20	195.33	209.55	201.68	215.90	208.03	222.25	214.38	247.65	239.78	273.05	265.18
7/16	Full thread		Full thread		Full thread		Full thread		16.00	6.86	19.05	9.91	22.35	13.21	25.40	16.26	28.45	19.56	31.75	22.61	35.05	25.91	38.10	28.96	41.15	32.26	44.45	35.31	47.75	38.61	53.85	44.96	60.45	51.31	66.55	57.66	73.15	64.01	79.25	70.36	85.85	76.71	91.95	83.06	98.55	89.41	104.65	95.76	111.25	102.11	117.60	108.46	123.95	114.81	123.95	114.81	130.05	121.16	136.65	127.51	142.75	133.86	149.35	140.21	155.45	146.56	162.05	152.91	168.15	159.26	174.75	165.61	180.85	171.96	187.45	178.31	193.55	184.66	200.15	191.01	206.25	197.36	212.85	203.71	218.95	210.06	244.35	235.46	269.75	260.86
1/2	Full thread		Full thread		Full thread		Full thread		Full thread		16.00	6.10	19.05	9.65	22.35	12.45	25.40	15.75	28.45	18.80	31.75	21.84	35.05	25.15	38.10	28.45	41.15	31.50	44.45	34.54	50.80	41.15	57.15	47.24	63.50	53.85	69.85	59.94	76.20	66.55	82.55	72.64	88.90	79.25	95.25	85.34	101.60	91.95	107.95	98.30	114.30	104.65	120.65	110.74	120.65	110.74	127.00	117.35	133.35	123.44	139.70	130.05	146.05	136.14	152.40	142.75	158.75	149.10	165.10	155.45	171.45	161.54	177.80	168.15	184.15	174.24	190.50	180.85	196.85	186.94	203.20	193.55	209.55	199.64	215.90	206.25	241.30	231.65	266.70	257.05
9/16	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		19.05	8.38	22.35	11.43	25.40	14.73	28.45	19.05	31.75	21.08	35.05	24.38	38.10	27.43	41.15	30.73	47.75	37.08	53.85	43.43	60.45	49.78	66.55	56.13	73.15	62.48	79.25	68.83	85.85	75.18	91.95	81.53	98.55	87.88	104.65	94.23	111.25	100.58	117.35	106.93	117.35	106.93	123.95	113.28	130.05	119.63	136.65	125.98	142.75	132.08	149.35	138.68	155.45	145.03	162.05	151.38	168.15	157.73	174.75	164.08	180.85	170.43	187.45	176.78	193.55	183.13	200.15	189.48	206.25	195.83	212.85	202.18	238.25	227.58	263.65	252.98
5/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		19.05	7.62	22.35	10.67	25.40	13.97	28.45	17.02	31.75	20.32	35.05	23.37	38.10	26.67	44.45	33.02	50.80	39.37	57.15	45.72	63.50	52.07	69.85	58.42	76.20	64.77	82.55	71.12	88.90	77.47	95.25	83.82	101.60	90.17	107.95	96.52	114.30	102.87	114.30	102.87	120.65	109.22	127.00	115.57	133.35	121.92	139.70	128.27	146.05	134.62	152.40	140.97	158.75	147.32	165.10	153.67	171.45	160.02	177.80	166.37	184.15	172.72	190.50	179.07	196.85	185.42	203.20	191.77	209.55	198.12	234.95	223.52	260.35	248.92
3/4	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		28.45	17.02	31.75	20.32	35.05	23.37	38.10	26.67	38.10	25.40	44.45	31.75	50.80	38.10	57.15	44.45	63.50	50.80	69.85	57.15	76.20	63.50	82.55	69.85	88.90	76.20	95.25	82.55	101.60	88.90	107.95	95.25	107.95	95.25	114.30	101.60	120.65	107.95	127.00	114.30	133.35	120.65	139.70	127.00	146.05	133.35	152.40	139.70	158.75	146.05	165.10	152.40	171.45	158.75	177.80	165.10	184.15	171.45	190.50	177.80	196.85	184.15	203.20	190.50	228.60	215.90	254.00	241.30
7/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		25.40	12.70	28.45	15.75	31.75	19.05	31.75	17.53	38.10	23.88	44.45	30.23	50.80	36.58	57.15	42.93	63.50	49.28	69.85	55.63	76.20	61.98	82.55	68.33	88.90	74.68	95.25	81.03	101.60	87.38	101.60	87.38	107.95	93.73	114.30	100.08	120.65	106.43	127.00	112.78	133.35	119.13	139.70	125.48	146.05	131.83	152.40	138.18	158.75	144.53	165.10	150.88	171.45	157.23	177.80	163.58	184.15	170.18	190.50	176.28	196.85	182.63	222.25	208.03	247.65	233.43
1	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		22.35	8.13	25.40	11.18	25.40	9.65	31.75	15.75	38.10	22.35	44.45	28.45	50.80	35.05	57.15	41.15	63.50	47.75	69.85	53.85	76.20	60.45	82.55	66.55	88.90	73.15	95.25	79.25	95.25	79.25	101.60	85.85	107.95	92.20	114.30	98.55	120.65	104.65	127.00	111.25	133.35	117.60	139.70	123.95	146.05	130.05	152.40	136.65	158.75	142.75	165.10	149.35	171.45	155.45	177.80	162.05	184.15	168.15	190.50	174.75	215.90	200.15	241.30	225.55
1-1/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		31.75	13.72	38.10	20.07	44.45	26.42	50.80	32.77	57.15	39.12	63.50	45.47	69.85	51.82	76.20	58.17	82.55	64.52	88.90	70.87	88.90	70.87	95.25	77.22	101.60	83.57	107.95	89.92	114.30	96.27	120.65	102.62	127.00	108.97	133.35	115.32	139.70	121.67	146.05	128.02	152.40	134.37	158.75	140.72	165.10	147.07	171.45	153.42	177.80	159.77	184.15	166.12	209.55	191.52	234.95	216.92
1-1/4	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		31.75	13.72	38.10	20.07	44.45	26.42	50.80	32.77	57.15	39.12	63.50	45.47	69.85	51.82	76.20	58.17	82.55	64.52	82.55	64.52	88.90	70.87	95.25	77.22	101.60	83.57	107.95	89.92	114.30	96.27	120.65	102.62	127.00	108.97	133.35	115.32	139.70	121.67	146.05	128.02	152.40	134.37	158.75	140.72	165.10	147.07	171.45	153.42	177.80	159.77	203.20	185.17	228.60	210.57
1-3/8	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		38.10	20.07	44.45	26.42	50.80	32.77	57.15	39.12	63.50	45.47	69.85	51.82	76.20	58.17	82.55	64.52	82.55	64.52	88.90	70.87	95.25	77.22	101.60	83.57	107.95	89.92	114.30	96.27	120.65	102.62	127.00	108.97	133.35	115.32	139.70	121.67	146.05	128.02	152.40	134.37	158.75	140.72	165.10	147.07	171.45	153.42	196.85	178.82	222.25	204.22
1-1/2	Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		Full thread		38.10	17.02	44.45	23.37	50.80	29.72	57.15	36.07	63.50	42.42	69.85	48.77	69.85	48.77	76.20	55.12	82.55	61.47	88.90	67.82	95.25	74.17	101.60	80.52	107.95	86.87	114.30	93.22	120.65	99.57	127.00	105.92	133.35	112.27	139.70	118.62	146.05	124.97	152.40	131.32	158.75	137.67	165.10	144.02	190.50	169.42	215.90	194.82

ASME Material Specifications

ASTM A193/A193M Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High Temperature or High Pressure Service and Other Special Purpose Applications
ASTM A307 Standard Specification for Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength
ASTM A449 Standard Specification for Hex Cap Screws, Bolts and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum Tensile Strength
ASTM A453/A453M Standard Specification for Bolting, Stud Bolts, Screws, Nuts
ASTM A354 Standard Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners
ASTM A320 Standard Specification for Alloy-Steel and Stainless Steel Bolting for Low-Temperature Service
ASTM A1082/A1082M Standard Specification for Bolting, Stud Bolts, Screws, Nuts
ASTM A1014/A1014M Standard Specification for UNS N07718 Bolting, Stud Bolts, Screws, Nuts
ASTM F468 Standard Specification for Nonferrous Bolts, Hex Cap Screws, and Studs
ASTM F593 Standard Specification for Stainless Steel Bolts, Hex Cap Screws, and Studs
ASTM F901 Aluminium Transmission Tower Bolts
ASTM F738 Stud Bolts, Screws
ASTM F1554 Anchor Bolts, Anchor Rods
ASTM F2281 Bolting, Stud Bolts, Screws, Hex Cap Screws, Threaded Rods
ASTM F3125 Heavy Hex Bolts, Screws, Studs