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.