What is the torque on a 7 8 bolt?
US Recommended Bolt Torque
| Size | Recommended Torque | |
|---|---|---|
| Grade 2 | Grade 8 | |
| 7/8″ | 129 | 501 |
| 1″† | 188 | 764 |
| * Sizes from #4 to #10 are in lb-in. Sizes from 1/4″ up are in lb-ft. † Fine thread figures are for 1″-14. Grade 2, 5, and 8 values are for slightly lubricated bolts. |
What is the torque on a Grade 8 bolt?
Tightening Torque Guide for Grade 5 & 8 Hex Cap Screws
| GRADE 5 | GRADE 8 | |
|---|---|---|
| Coarse Thread | Coarse Thread | |
| Size | Clamp Load | Size |
| 1/4-20 (.250) | 2025 | 1/4-20 (.250) |
| 5/16-18 (.3125) | 3338 | 5/16-18 (.3125) |
How is bolt torque value calculated?
DETERMINING TORQUE The general equation for bolt load based on applied torque is T = KFiDb where K = torque coefficient. K is a function of the coefficients of friction and collar friction in the joint, and these are based on variables such as surface finish, coatings, and so on.
What is torque value?
How is torque measured? The measure of torque equals force multiplied by distance. A lug nut, for example, may have a torque value of 75 foot-pounds. Imagine having a wrench 1 foot in length with a 75-pound weight at the end, this resulting force is equal to a torque of 75 ft-lbs.
What is the proper torque spec for a bolt?
In general the proper torque spec is usually around 65-70% of the failure torque rate. The below chart refers to usage in steel. Proper torque spec varies depending on the material, bolt grade or wether lubrication is used such as oil, wax, or anti-seize Always go to the manufacturer for proper torque specs if needed.
What happens if a bolt is over or under torqued?
An over-torqued bolt that is stretched beyond its elastic limit is severely weakened, diminishing its effective load capacity. An under-torqued bolt or screw will allow negligible separation between the workpieces, which seems trivial at first, but after consistent dynamic loading or other operating stresses, the gap between workpieces will grow.
How do you find the torque value of a zinc bolt?
As an example, we can utilize the equation to find the correct torque value for a zinc-plated, heavy structural bolt, in this instance belonging to ASTM A325 with a ¾ inch diameter and 10 TPI. As = π/4 x (3/4in. – (.938194/10))² As =.3383 in² Using this value, the clamp force can now be identified.
How much torque is reduced for longer fasteners?
For longer fasteners, the torque is reduced significantly. Clamp loads are based on 75% of the minimum proof loads for each grade and size. Proof load, stress area, yield strength, and other data is based on IFI 7th Edition (2003) Technical Data N-68, SAE J429, ASTM A307, A325, A354, A449, and A490.