A rivet is a short cylindrical bar with a head integral to it.The cylindrical portion of the body is called as shank or body and the lower portion called as tail.Rivets are used to make permanent joining between plates,metals,bridges,tanks etc and for joining light materials. Joining and fastenings are divided into two types such as –
- Permanent Fastenings–These are the fastenings which can not be dissembled without destroying the component.e.g-shouldering,welding etc.
- Temporary Fastenings-These fastenings can be dissembled without destroying the component.e.g-screwed,keys etc.
Methods of Riveting
The function of a rivet in a joint to make it strong and tight,high strengthened.The strength is necessary to prevent failure at joint and the tightness provides required leak proof facility.When two plates are to be joined by a rivet then the holes in the plates area are punched or reamed or drilled.Punching is the cheapest method but in punching irregularity occurs at the sight of the hole ,So drilling is more effective. The plates are drilled together and then separated to remove any disorder as as to have a tight flush joint between the plates.Then a cold rivet or a hot rivet is introduced.When hot rivet is used then the process called as Hot Riveting and similarly when cold rivet is used it called as Cold Riveting. The cold riveting is used for structural joints and the cold riveting is used for making leak proof joint. The riveting may be done manually or automatically by riveting machine.When it done by hand the original rivet head is backed up heavy bar or hammer into the die or set .This causes the shank to filling the hole then it called as point.
Types of Rivet
- Lap Joint:A lap joint is that in which one plate overlap the other and the two plates are then riveted.
- Butt Joint:A butt joint is the type of joint where the main plate are kept in alignment butting to each other and another plate or cover plate is placed either one side or both the sides of the plates.Then the cover plate is riveted with the other plates.It can be of two types such as Single strap butt joint(The edges of main plates butt against together and only one cover plate is provided at one side of the main plate & then riveted together) and Double strap butt joint(The edges are joint to each other and two cover plates are placed at two sides of the main plate and then riveted with each other).