Chapter 4:
Sheet Metal Forming
2. WORKING TOOLS AND
MACHINERY
Shafizan Bt. Shariffuddin
School of Manufacturing Engineering
UniMAP
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
(a)
(b)
Figure 16: (a) Straight handle and (b) pistol grip
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