Steel Rule: It is particularly useful in measuring and laying out small size of work. It is shown in Figure 21.14.
Figure 21.14 Steel Rule
Steel Square: This is L-shaped hardened steel piece. It has two parts: tongue and body.
The narrow arm of the square is known as tongue while the wider part is called as body as shown in Figure 21.15. It is used for checking the 90° between two adjacent surfaces and for making the line in perpendicular direction to any base line.
Figure 21.15 Steel Square
Snips: These are made of high carbon steel and used for cutting thin and soft metallic sheets. There are different types of snip (Figure 21.16) but straight and curved or bent types of snip are commonly used in practice. The straight snip or shear is used for cutting along a straight line while the curved or bent type of snip is used for cutting the sheet along a curvature. Both these snips are very light and can be easily handled by only one hand. A heavier class of snip is known as bench strip or bench shear which is fitted on bench.
Figure 21.16 Type of Snips
Punches: These are also made by hardened steel. Punches are used for marking out work and to locate the centre in a permanent manner. Punches may be divided in two types: prick punch or dot punch, centre punch
Prick punch is used to make small marks and to make this prick punch marks larger, we have to use centre punch. Centre of the hole that is to be drilled is marked by centre punch.
Dividers: It is made by hardened steel and generally used for drawing or scratching the circles or arcs on the metallic sheet.
Trammel: It consists of a steel bar with two movable steel heads which have bottom part sharply pointed and hardened. Main function of this trammel is to draw large sizes of circles or arcs that are beyond the limit of dividers.
Hammers: To suit the different types of work on tin sheet, various sizes and shapes of hammers are used (Figure 21.17). They are made to have square or round heads to suit for striking or hammering the corners and round surfaces, respectively. If the peen of the hammer is straight and parallel to axis of hammer (handle), this is known as straight peen hammer; if the peen of the hammer is straight and perpendicular to axis of hammer (handle), this is known as cross peen hammer; and if the peen of the hammer is round, this is known as ball peen hammer. For avoiding the damage of sheet, soft faced hammers are frequently used.
Figure 21.17 Type of Hammers
Mallet: This is also used for striking purpose and is made of hard rubber, lead, copper, or mostly of hard wood (Figure 21.18).
Figure 21.18 Mallet
Pliers: These are used for holding and forming the various shapes and patterns (Figure 21.19). In general, flat nose and round nose pliers are widely used.
Figure 21.19 Pliers
Slip Gauge or Thickness Gauge: It is used to measure the clearance between two assembled parts (Figure 21.20).
Figure 21.20 Slip Gauge
Sheet Metal Gauge: This is used to measure the thickness of sheets as shown in Figure 21.21.
Figure 21.21 Sheet Metal Gauge
Stakes: Stakes are used for seaming, bending, or forming operations. They actually work as supporting tools as well as forming tools. As per nature of work some useful forms of stake are shown in Figure 21.22. In forming operation for long tapered cylindrical items, a bick iron is used while the hatched stake is preferred for forming, seaming, and bending the edges. For conical work, a funnel stake is very useful. Half moon stake is very useful for working the edges on discs. For spherical work, a convex stake is preferred. Pipe stake is used for forming tubes. Horse type of stake is used for bending and general work for holding and supporting the other stakes.
Figure 21.22 Type of Stakes
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