Chapter 4: Sheet Metal Forming Shafizan Bt. Shariffuddin School of Manufacturing Engineering UniMAP 2. WORKING TOOLS AND MACHINERY

TOOLS AND MACHINERY It is essential that we know how to select and properly use both the hand and machine tools of the sheet metal. When we do this :- –The quantity of the work will improve. –We will save valuable time. –Our work will be easier.

HAND TOOLS Sheet metal hand tools are used to :- –Scribe or measure lines –Perform lay-out operations –Shape or cut metal

Scratch awls There are three common types of scratch awls (scribers) as shown in Figure 1. All three awls perform the same function of making lines on metals. Figure 1.Commonly used scratch awls scribe lines on metal for a variety of purposes.

Dividers Dividers are manufactured in a number of sizes and types and are used to :- –space off equal distances –to divide lines equal parts –to scribe arc and circles Figure 2. Wing dividers transfer dimensions and scribe arcs and circles.

Steel square The steel square shown in Figure 3 is invaluable for accurate layout work in pattern drafting since all layout must start from a square corner. Figure 3. Steel square are used for accuracy in transferring layout.

Trammel points Trammel points sometimes called a beam compass, shown in Figure 4, are instrument used for drawing large circles, arcs, etc., Figure 4. Trammel points or beam compasses are normally in 0.5 or 1 mm lengths or multiples those length and are used to draw large circle, arcs and similar shapes requiring accuracy.

Rules Rule instruments are manufactured in a variety of lengths and types; each of which is designed for measuring or laying out different work. Basically, there are three types of rules :- Folding rule Steel circumference rule Tape rule or flexible push-pull rule Figure 5. Folding, circumference and tape rule instruments take measurements necessary for many sheet metal job.

Punches Punches are intended for :- Establishing points or small indentations or establishing points for dividers and trammel point. Marking the location of points and centers of holes to be drilled. Cutting circular holes. Great care should be used in order to select the proper punch for each operation. The common hand punches are shown in Figure 6. Figure 6.Common types of punches employed to make round holes in sheet metal.

Hand groover The hand groover shown in Figure 7 is used when grooving a seam by hand. The end of the tool is recessed to fit over the lock, making the grooved seam. It is available in various sizes. Figure 7.Hand groover

Rivet set The rivet set shown in Figure 8 is made of tool steel. The deep hole in the bottom is used to draw a rivet through metal. The cup-shaped is used to form the finished head of a rivet. The hole in the side is to release the burrs that are punched through the metal with the rivet. Figure 8.Rivet set

Chisels The various type of chisels shown in Figure 9 are used for cutting and shaping metal. Figure 9. Common chisels used in the process of cutting and shaping metals (flat, cape, diamond-point, and round nose chisel)

Hammers It is essentials that sheet metal workers have a variety of hammers. These should include the following :- –riveting –setting –nail –raising –ball pein Figure 10. Sheet metal workers require a variety of hammer types.

Mallet Mallet is one of the most abused tools because it is often used to perform operations for which it is not designed. Mallets are properly used where steel hammers would deface the work. It is made of good grade of hickory or hard fiber. See Figure 11. Figure 11: Mallet

Snips Snips of various types shown in Figure 12, are indispensable to the sheet metal workers. Left hand offset snips Right hand offset snips Figure 12: Some types of snips

Two basic types of the snip’s blade : –Straight blade: the face of the blade running straight up from the cutting edge. –Combination blade: the blade is curved back from the cutting edge which allows the metal to slide over the top blade when cutting curves as shown in Figure 13. Figure 14 shows the different between the straight and combination blade.

Figure 13. Combination snips blades permit metal to slide over top blade making it easier to cut and curved edges. Straight blade snips are the best used on sheet metal which is to be cut in a straight line.

Figure 14. Straight and combination blades are the two most common types employed in sheet metal snips.

Pliers Pliers are used in sheet metal work for :- holding cutting bending

Hacksaws There are two styles of hacksaw frames used by the sheet metal worker. These are shown in Figure 16. –Straight handle-usually preferred for fine work. –Pistol grip Figure 16: (a) Straight handle and (b) pistol grip (a) (b)

Files There are a number of files of various kinds and shapes. Files are used to :- –Remove burrs from sheets of metal. –Square the ends of band iron. –Straighten uneven edges. –Remove small amount of metal.

Bench stakes Various types of anvil which are referred as stakes, are designed to perform many operations for which machines are not available or readily adaptable. The shark of each stake has a tapered point which fits the holes in the bench plate. These stakes are available in a various shapes and sizes. The more common stakes are shown in Figure 18.

Figure 18: Various types of bench stake