Author: haroonkhan

The sheet of black iron, tin, galvanized iron (GI), stainless steel, copper, zinc, aluminium, etc. are widely used in tin smithy work. The sheets are specified by gauge numbers. The larger the gauge number, the lesser the thickness. Black Iron Sheet: It is the cheapest type of metallic sheet. It has a bluish black appearance and…

Figure 21.13 shows the common types of sheet metal joints. Figure 21.13 Sheet Metal Joints Lap Joint: It is the simplest and common type of joint that can be prepared by means of soldering or riveting processes. Seam Joint: A seam is a joint made by fastening two edges to each other. Hem Joint: Hem is an edge or border…

Sheet metal is thin and flat pieces of metals. It is one of the fundamental forms used in metalworking and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material. Thicknesses can vary significantly, although extremely thin thicknesses are considered as foil or leaf, and pieces…

Trimming: The excess metal which remains around parting lines or around other edges after previous operations, such as forging, die casting, and drawing of sheet metal parts is removed by ‘trimming’. Trimming dies are similar to blanking dies and the parts are forced through the die by suitable punch. Shaving: A very small amount of metal (about…

It is a method to produce seamless tubes. The piercing machine consists of two taper rolls and a cylindrical hot billet passed between these rolls over a mandrel as shown in Figure 21.12. Both the rolls revolve in the same direction and the billet is centre punched. The hot billet is pushed forward into the rolls.…

In thread rolling there is no chips formation, i.e., the threads are produced by plastic deformation. Two types of machines are used, namely, reciprocating flat die machine and rotating cylindrical die machine. In a flat die method (Figure 21.11a), the cylindrical blanks are automatically fed from a hopper and placed upon a stationary flat hardened…

Just as in electrohydraulic forming, the electrical energy is first stored in a capacitor bank. This energy is then discharged through a coil by closing the switch. The coil produces a magnetic field, the intensity of this field depends on the value of the current. Since the metallic workpiece is in this magnetic field, a…

Electric discharge in the form of sparks in the place of explosives can also be used to generate a shock wave in a fluid. An operation using the principle of generating a shock wave is called electrohydraulic forming. The characteristics of this process are very similar to those of explosive forming. The capacitor bank is…

In the explosive forming (Figure 21.10), shock wave is generated in a fluid medium by detonating an explosive charge. The entire wavefront is utilized in a confined space. But, for large object the wavefront may be used for unconfined space and it is less effective than confined space. The typical explosives include TNT and dynamite…