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Engineering Study Notes p107-110 - Coggle Diagram
Engineering Study Notes p107-110
Sheet Metalwork
Bench Shears
The bench shears are used for cutting sheet metal, plates and bars.
When the shears is not in use bolt should be fitted through the hole to prevent the shears being closed accidentally and causing accidents
Snips
Snips are used for cutting thin sheet metal by hand
Snips should never be used to cut wire, as this would damage the blades
Examples include
The universal snips
They are used for straight cuts as well as inside and outside curves
The curved snips
Are used for cutting curves, especially inside curves
The straight snips
Are used for straight cuts or outside curves
Mallets
Mallets are used for bending and shaping materials without damaging the surfaces of the materials
The handles are made from cane or ash
Sheet Metal Punch
They are used for cutting holes in metal up to 1.5mm
Paning Hammers
It is used for folding down metal edges in restricted places
e.g tucking in the edge of the sheet metal
Folding Bars
They are used for bending sheet metal
They are held in a vice, and when the vice is tightened, the bars grip the material
Groove Punch or groovers
They are used for closing down wired edges and for interlocking grovved seams
Stakes
It is used for shaping sheet metal
If gripping in the vice, clamps should be used; otherwise, their shanks will become rough and uncomfortable to handle
Forming Edges
Beaded edges and wired edges are formed on sheet metal articles to strengthen them and also to make them safe
Stages in forming a beaded edge
3 Bend it further on a hachet stake
4 Fold it around a thin metal strip
2 Hold material in folding bars and bend over
5 Close the bead with the mallet, do not flatten it out
1 Allow 3 to 6mm for the bead
Stages in forming a wired edge
3 Bend the edges further on the hatchet stake (see appendix page 211)
2 Hold material in folding bars and form a round bend
4 Fold down on a flat strip with a rounded edge and of the required thickness
1 Allow 2 1/2 times the diameter of the wire for the edge
5 Fit wire and bend down the material to hold it
6 Close down the material with a groove punch (a creasing iron may also be used for this purpose)
7 Tucking in the material with a panning hammer
Beaten Metalwork
Hollowing
This is a method of forming bowl-shaped articles
This involves the shaping of sheet metals by the use of a hammer or a mallet
Do not forget to add the acid to the water and not the other way round
Sinking
This is a method of forming hollow flat-rounded articles such as small trays
Planishing
Articles formed by processes such as hollowing and sinking are planished to remove marks and small irregularities and to work-harden the material
The workpiece is often polished after planishing
Bending
It is used for folding bars should only be used for bending sheet metal
Twisting
It is used for decorative purposes. Square bars, up to about 10mm, can be twisted cold.