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Insufficently torquing causes assembly looseness which can lead to equipment catastrophic failure

Bolting joint depends on the clamping load. The clamping load is proportional to tightening torque and friction factor that varies with amount of scale on the nut, plating, lubrication, etc...

Following is the table of Recommended Tightening Torque Values for Steel Bolts and Studs. Clamping load values are calculated based on bolted surface uniformity.

Clamping load significantly reduces, if bolt bearing face is not true and flat. To make sure your equipment securely bolted, contact Vibratechnica for evaluation testing.


		SAE 2			SAE 5			SAE 7			SAE 8
I.D. Mark		No Marks			3 Lines			5 Lines			6 Lines
Material		Low carbon			Medium-carbon, tempered			Medium-carbon, quenched & tempered			Medium-carbon, quenched & tempered
Tensile strength (Minimum)		74,000 psi			120,000 psi			133,000 psi			150,000 psi
Size	Diameter in	Clamp Load lb	Tightening Torque (lb - ft)		Clamp Load lb	Tightening Torque (lb - ft)		Clamp Load lb	Tightening Torque (lb - ft)		Clamp Load lb	Tightening Torque (lb - ft)
Size	Diameter in	Clamp Load lb	Dry (K=0.2)	Oil (K=0.15)	Clamp Load lb	Dry (K=0.2)	Oil (K=0.15)	Clamp Load lb	Dry (K=0.2)	Oil (K=0.15)	Clamp Load lb	Dry (K=0.2)	Oil (K=0.15)
4 - 40	0.1120	240	0.4	0.3	380	0.7	0.5	450	0.8	0.6	540	1.0	0.8
4 - 48	0.1120	280	0.5	0.4	420	0.8	0.6	520	1.0	0.7	600	1.1	0.8
6 - 32	0.1350	380	0.9	0.6	580	1.3	1.0	720	1.6	1.2	820	1.8	1.4
6 - 10	0.1350	420	0.9	0.7	640	1.4	1.1	800	1.8	1.4	920	2.1	1.6

8 - 32	0.1640	588	1.6	1.2	900	2.5	1.8	1100	3.0	2.3	1240	3.4	2.5
8 - 36	0.1640	600	1.6	1.2	940	2.6	1.9	1160	3.2	2.4	1320	3.6	2.7
10 - 21	0.1900	720	2.3	1.7	1120	3.5	2.7	1380	4.4	3.3	1580	5.0	3.8
10 - 32	0.1900	820	2.6	1.9	1285	4.1	3.1	1550	4.9	3.7	1800	5.7	4.3

1/4 - 20	0.2500	1320	5.5	4.1	2020	8.4	6.3	2500	10	7.8	2860	12	8.9
1/4 - 28	0.2500	1500	6.3	4.7	2320	9.7	7.3	2860	12	8.9	3280	14	10
5/16 - 18	0.3125	2160	11	8.4	3340	17	13	4120	21	16	4720	25	18
5/16 - 24	0.3125	2400	13	9.4	3700	19	14	4560	24	18	5220	27	20

3/8 - 16	0.3750	3200	20	15	4940	31	23	6100	38	29	7000	44	33
3/8 - 24	0.3750	3620	23	17	5600	35	26	6900	43	32	7900	49	37
7/16 - 14	0.4375	4380	32	24	6800	50	37	8400	61	46	9550	70	52
7/16 - 20	0.4375	4900	36	27	7550	55	41	9350	68	51	10700	78	59

1/2 - 20	0.5000	5840	49	37	9050	75	57	11200	93	70	12750	106	80
1/2 - 12	0.5000	6600	55	41	10700	89	67	12600	105	79	14400	120	90
9/16 - 12	0.5625	7500	70	53	11600	109	82	14350	135	101	16400	154	115
9/16 - 18	0.5625	8400	79	59	12950	121	91	16000	150	113	18250	171	128

5/8 - 11	0.6250	9300	97	73	11400	119	89	17300	180	135	20350	212	159
5/8 - 18	0.6250	10600	110	83	16300	170	127	20150	210	157	23000	240	180
3/4 - 10	0.7500	13800	173	129	21300	266	200	26300	329	247	30100	376	282
3/4 - 18	0.7500	15400	193	144	23800	298	223	29400	368	276	33600	420	315

7/8 - 10	0.8750	11400	166	125	29400	429	322	36400	531	398	41600	607	455
7/8 - 14	0.8750	12600	184	138	32400	473	354	40100	585	439	45800	668	501
1 - 8	1.0000	15000	250	188	38600	643	483	47700	795	596	54500	908	681
1 - 12	1.0000	16400	273	205	42200	703	528	52200	870	653	59700	995	746

1 1/8-7	1.1250	18900	354	266	42300	793	595	60100	1127	845	68700	1288	966
1 1/8-12	1.1250	21200	398	298	47500	891	668	67400	1264	948	77000	1444	1083
1 1/4-7	1.2500	24000	500	375	53800	1121	841	76300	1590	1192	87200	1817	1363
1 1/4-12	1.2500	26600	554	416	59600	1242	931	84500	1760	1320	96800	2017	1513

1 3/8-6	1.3750	28600	655	492	64100	1469	1102	91000	2085	1564	104000	2383	1788
1 3/8-12	1.3750	32500	745	559	73000	1673	1255	104000	2383	1788	118400	2713	2035
1 1/2-6	1.5000	34800	870	653	78000	1950	1463	111000	2775	2081	126500	3163	2372
1 1/2-12	1.5000	39100	978	733	87700	2193	1644	124000	3100	2325	142200	3555	2666

- SAE 2 size from 7/8 - 10 to 1 1/2 using low carbon steel whose minimum tensile strength is 54000 psi

- SAE 5 size from 1 1/8 to 1 1/2 using medium carbon steel whose minimum tensile strength is 105000 psi