How can you tell the torque of a fastener?
How can you tell the torque of a fastener?
After tightening the bolt, mark the bolt surface and that of the product or workpiece. Then loosen the bolt. Re-tighten it until the markings re-align. The torque needed to return the bolt to its original position is the torque value of the bolt.
When do you apply torque to a bolt?
Torque is only the amount of energy is takes to spin (think twisting force) the nut along the threads of a bolt. Torque must be applied to tension a bolt. Bolt torque is usually greater affected by lube, thread condition and exposure to weather. Tension is what we’re actually after here.
How is torque related to pre load force?
The relationship between bolt torque and its corresponding pre-load force (tension) is given in the following formula… Bolt torque provides only an indirect approximation of material stress. It is estimated that only about 10% of the tightening torque actually results in useful bolt tensioning.
How does torque depend on the geometry of the bolt?
How much torque that requires depends on the geometry of the bolt and whether the threads are lubricated. (Lubricated threads require less torque to get to the same clamping force, because there is less friction to overcome during the tightening.)
What are the torque specifications for a metric bolt?
Metric Bolt Torque. If the bolt diameter is 5 mm, thread series is Coarse, ISO 898-1 Property Class is 8.8, then. Torque for Ecoguard Bolt is 4.0 Nm, Lubricated is 4.6 Nm and dry is 6.2 Nm.
What are the torque requirements for bolts?
The required bolt clamping force for a joint is 20000 lbs. The torque required for a 3/4″ dry steel bolt to achieve this tension can be calculated as. T dry = (0.2) (20000 lb) (0.75 in) = 3000 (in lb)
What are the torque settings for head bolts?
SOURCE: head bolts torque settings According to my haynes manual for G-S reg, 1989-1998 it goes as follows, Stage 1:- Tighten all bolts by hand until bolt heads just contact cyl. head. Stage 2:-Tighten all bolts to 40Nm or 30lb ft. Stage 3:-Angle tighten all bolts a further 60 degrees. Stage 4:-Angle tighten all bolts again a further 60 degrees.
How do you calculate bolt tension?
Determine the tension force on the bolt. This can also be measured using a force transducer (again, if the value is not already known). Assume the tension force is 3 lbs. Subtract the preload force from the tension force. In our example, the tension force (2 lbs.) subtracted from the preload force (3 lbs.) gives 1 lbs.
