Bolts

Bolts consist of cap screws. These cap screws holds together to join two different parts. The screw threads fasten together to hold them tightly. Bolted joints are very commonly used in constructions and machine designs.

Types of Bolted joints

There are two types of bolted joints. In the first method the bolt is fastened to a calculated torque to produce a clamp load. The joint is designed as such that the force acting on the joint could never overcome the clamp load thus there is no relative motion seen on the joint. In the second type the clamps are not designed as such but the whole joint completely relies on the strength of the bolt shaft.

Making of Bolts

The clamp load of a cap screw is created when certain torque is applied on it. The cap screw is stretched when it is tightened, thus parts that are captured get compressed resulting in a spring like assembly. Thus due an even distribution of strain it is an perfect engineering model. Until and unless the forces acting on the compressed parts does not exceed the clamp load there is no increment of load on the cap screw.

Locking mechanism

There are many locking mechanisms in place to prevent the bolts from coming loose. They are mainly required where the clamp load is low or even non-existent, even where the hardware used is inexpensive or where extra safety is required. There are several ways to lock like two nuts tightened on each other. There are many specialized equipments like lock washer, lock wire and thread adhesive being used for locking the bolts.

Types of Bolts

There are many types of bolts like cap screw, which is fastened around a cap, then machine screw, which is fitted with the help of a machine, and stud, which is hammered inside.

Failures of Bolted joints

Bolts generally fail if the operating forces produce loads, which exceed clamp loads, it loosens the joints. Overtorquing also causes failure as it damages the thread and the hardware.