First Year Engineering

Class Notes and Homework Workbook

First Year Metalwork

Topics to be covered

• Safety.• Bench tools.• Properties of Materials• Metals.• Drilling• The Centre Lathe.• Joining.

SAFETY

‘Accidents do not just happen, there is always a cause for

them’

Safety in Technical Rooms

• My class may not use machines without a teacher in the room.

• I may not use equipment that I have not been shown how to use.

• All accidents must be reported to the teacher.• Be prepared for class.• I will not be allowed to work if my behaviour puts

myself or others in danger.

Signed . . . . . . . . . . . . . . .

Seven Safety Hazards

• Hair – Example: long hair should be tied back.• Eye protection – • Hot metal – • Sharp metal and tools -• Clean workplace -• Fire -• Fumes -

Bench tools• Bench tools layout

• benct tools dia

Bench tools• Cold Chisels• similar to punches• used to cut metal

• Spring dividers• similar to a compass• used to draw circles.• Set radius using adjusting nut• puc mark can be used to hold it on the centre

• Engineers tri-square.• Used to mark lines at 90 degrees on materials.• Used to check corners are square.• Handle called stock other part called blade• Engineers rule.• This is a steel ruler.• Only millimetres are to be used

Bench tools• Cold Chisels• similar to punches• used to cut metal

• Spring dividers• similar to a compass• used to draw circles.• Set radius using adjusting nut• puc mark can be used to hold it on the centre

• Engineers tri-square.• Used to mark lines at 90 degrees on materials.• Used to check corners are square.• Handle called stock other part called blade• Engineers rule.• This is a steel ruler.• Only millimetres are to be used

Bench tools• Bench vice • made from cast iron• bolted to the table• used with vice clamps (protects the work piece)• Ball pein Hammer • name from rounded side• used with dot punch and chisels only• must be held at the end of the handle• The scriber• used to draw lines on the metal• made from carbon steel (wont wear).• The Dot / Centre punch.• Used to mark the centre of a hole for drilling (puc).• Used to mark along a line especially steel.• made from High carbon steel (hardened and tempered)

Properties of Materials

In other word the characteristics of a particular metal or material. (Or

how that metal/material is different to

others.)

Surface properties

• Colour• Transparent or Opaque• Reflection• Lustre (Also known as shine e.g. gold/silver )

Mechanical properties

• Hardness: • resistance to scratching or indentation.

Hardness can be tested by:• Brinell,• Vickers or • Rockwell hardness testers.

Mechanical properties• Malleability: • the ability to be beaten or rolled into thin

sheets, e.g. aluminium, copper, etc.• Ductility: • allows a material to be drawn into wire,

e.g. copper, brass, steel, etc.• Elasticity:• allows a material to return to it’s original

shape after it has been deformed, e.g. rubber.

Electrical properties

• Electrical conductor: • allows electrical current to flow, e.g.

copper. • Electrical insulator:• prevents current flowing, e.g. Polymers

(Polystyrene, polycarbonate, nylon.)

Thermal properties

• Melting point: • the temperature at which a material turns to a

liquid.

• Thermal conductor: • will transmit heat, e.g. copper.

• Thermal insulator: • will slow down or prevent heat from escaping,

e.g. polystyrene foam.

Mechanical properties• Brittleness: • can be fractured easily by impact, e.g. glass.

• Toughness: • can withstand blows or impact. (Hammer blows.)

Or tested by Charpy or Izod impact testers.

• Strength:• a measure of the ability to withstand forces such

as tension, compression or torsion.