First Year Metalwork.

1. First Year Metalwork. Class Notes and Homework Workbook

2. Second Year Metalwork Topics to be covered • Safety. • Bench tools. • Properties of Materials • Metals. • Drilling • The Centre Lathe. • Joining.

3. SAFETY ‘Accidents do not just happen, there is always a cause for them’

4. 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 . . . . . . . . . . . . . . .

5. Seven Safety Hazards • Hair - long hair should be tied back. • Eye protection - • Hot metal - • Sharp metal and tools - • Clean workplace - • Fire - • Fumes -

6. Bench tools • Bench tools layout • benct tools dia

7. 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

8. 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

9. 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)

10. Properties of Materials

11. Surface properties • Colour • Transparent or Opaque • Reflection • Lustre

12. Mechanical properties • Hardness: • resistance to scratching or indentation. Hardness can be tested by: • Brinell, • Vickers or • Rockwell hardness testers.

13. Mechanical properties • Malleability: • the ability to be beaten 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.

14. Electrical properties • Electrical conductor: • allows electrical current to flow, e.g. copper. • Electrical insulator: • prevents current flowing, e.g. pvc.

15. 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.

16. Mechanical properties • Brittleness: • can be fractured by impact, e.g. glass. • Toughness: • can withstand blows or impact, it is tested by Charpy or Izod testers. • Strength: • a measure of the ability to withstand forces such as tension, compression or torsion.

17. Metals Ferrous Metals Non-ferrous Metals Alloys.

18. Useful Terms for metals • Ferrous Metals. • Any metal that contains iron is a ferrous metal. • Non ferrous metals. • This is any metal that does not contain iron. • An alloy. • This is a mixture of two or more metals. • The charge. • These are the materials that are put into the furnace to produce the metal. • The operation (smelting). • This is how the furnace works how it makes the metal. • The products. • These are the materials that come out of the furnace.

19. Ferrous Metals.All metals that contain iron are ferrous metals

20. Blast furnace • The blast Furnace.

21. Blast furnace Charging bells

22. Blast Furnace • The Charge : • iron ore, • coke, • limestone. • Operations • the charge is loaded into the furnace using the charging bells. The coke burns when hot air is blown in through the tuyere “the blast” and the impurities mix with the limestone to give slag. The slag is taken off leaving molten iron to be tapped off. • The Products : • molten iron, • Slag • waste gasses

23. Basic Oxygen Furnace. • The basic Oxygen Furnace.

24. Basic oxygen Furnace • Stages in Production.

25. Basic oxygen Furnace. • The charge: • Molten Iron and • scrap steel • limestone • The operation: • charging • the blow (water cooled oxygen lance) • sampling • tapping (molten steel) • emptying slag • The products • molten steel • slag • waste gasses

26. Basic oxygen furnace • The Charge : • molten iron • scrap steel • limestone. • Operations • Scrap charging • molten iron charging • oxygen lance lowered in (water cooled. • The blow • sampling • slagging • tapping • The Products : • molten steel, • Slag • waste gasses

27. Basic oxygen Furnace. • The charge: • Molten Iron and • scrap steel • limestone • The operation: • The furnace is charged firstly with scrap steel. Molten iron from the blast furnace is then charged. • The oxygen lance is then lowered in and oxygen is blown in causing the impurities and extra carbon to mix with the limestone making slag. The lance is kept cool with water. The steel is sampled to check for the right amount of carbon. The furnace is tilted and the molten steel poured out through the tapping hole. The slag is then emptied out the top. • The products • molten steel • slag • waste gasses

28. Electric Arc Furnace. • The electric arc furnace.

29. Electric arc furnace • The Charge : • molten iron • scrap steel • limestone. • Operations • the lid containing the electrodes are lifted off the furnace and the furnace is charged. The lid is replaced and electricity is passed down the rods. This jumps from the rods to the metal causing it to melt. The impurities mix with the limestone to form slag. The slag is taken off. The furnace is then rotated on the rollers and tapped. • The Products : • molten steel • slag.

30. The Electric Arc. • The charge: • Molten Iron and • scrap steel • limestone • The operation: • the carbon rods and roof are lifted off. The furnace is charged. The rods are lowered and an arc is made between the charge and the rods producing heat. The steel is sampled. The furnace is on rollers and is tilted for slagging and then tapping. • The products • High Quality molten steel • slag

31. Non Ferrous Metals. • Aluminium. This is silver in colour, it is very strong but light and is malleable and ductile. It is a good conductor of heat and electricity. An oxide forms on the outside preventing corrosion. It is used for aircraft bodies, drinks cans, high tension wires. • Copper. This is reddish brown in colour and is malleable and ductile. It is a good conductor of heat and electricity. It turns green as it corrodes. It is used in electrical wiring, heating pipes and for roofing.

32. Non Ferrous Metals. • Lead. This is a very heavy metal, it is a dull grey colour and is flexible at room temperature. It is poisonous if handled to often. It is used for making batteries and also for roofing. • Zinc This is a grey colour. It does not corrode easily and so it is used for galvanizing (coating steel) to stop rusting. • Tin This is a silvery white metal, it is weak and generally combined with other metals.

33. Alloys. An alloy: is a mixture of two or more metals. Steel is one example. • Brass. This is a combination of copper and zinc. It is a gold colour and does not rust easily. It is used to make hinges, screws, outside taps and musical instruments. • Bronze. This is a combination of copper and tin. It is a dark green colour and is easily cast making it ideal for statues. • Soft solder. This is a combination of lead and tin. It has a very low melting point and so it can be used to join electronic components.

34. Machine tools The Pillar drill. The Centre lathe.

35. The Pillar Drill.

36. The Pillar Drill • The Base • this is made from cast iron and is bolted to the floor. It can be used to support large pieces when drilling. • The column • This is attached to the base and supports the table as well as the motor spindle and the gears. • The table. • This is attached to the column and can be moved up or down and can be rotated. • The chuck • This is connected to the spindle and is used to hold parallel shank drills. The chuck is tightened using the chuck key.

37. The Pillar drill. • The Feed Lever. • This moves the drill to and from the piece. • Adjustable depth stop. • This is used to set the required depth of the hole. It stops the drill going all the way through the piece unless required. • The Motor. • This takes electricity and turns it into rotary motion powering the spindle. • The spindle and gears. • Different gears are needed for different jobs. The gears are connected to the motor and the spindle allowing it to turn at different speeds.

38. The Pillar drill. • Using the Drilling Machine • make sure long hair is tied back. • have no loose clothing. • Always wear safety glasses. • Never use the machine if the teacher is not present. • make sure the work is properly held. • make sure the drill speed is correct. • Have a dot punch in the center of the hole and center the drill on it. • Make sure not to pull the feed lever to hard when breaking through the piece • never drill into the table or machine vice. • Always check the drill size before drilling.

39. The Pillar drill. • Holding the work for drilling. • The machine vice. • This is the most common way of holding work. The piece should be clamped by two square edges and supported by wood underneath. The piece must be held level to ensure a round hole. • The machine table. • The machine table can be used to hold larger heavier work. The piece can be bolted to the table using clamps. The table can be lowered and rotated for difficult pieces. • The base. • The base can also have pieces bolted to it but this is unusual.

40. The Pillar drill. • Pilot hole. • This is used before drilling a large hole so as to keep the drill centred.

41. The Pillar drill. • Tapping hole. • This is drilled before threading a hole. The hole must be smaller than the tap being used.

42. The Pillar drill. • Clearance hole. • This hole is slightly larger than the bolt or bar passed through it.

43. The Pillar drill. • Blind hole. • This is a hole that does not go all the way through a piece.

44. The Pillar drill. • Countersink hole. • This enlarges the top of the hole and allows the head of a screw to sit in flush to the piece.

45. The Pillar drill. • Counterboring. • This also enlarges the top of the hole to allow cheese head screws to fit in flush to the piece.

46. The Pillar drill. • Parts of the drill bit. • The point angle of a drill bit is 118 degrees. jc79

47. The Pillar drill. • Types of drill bit. • The Parallel shank. • This is used mostly for small size drills and is held in a chuck. • Morse taper shank. • This is used for larger drills and fits directly into the spindle or the tailstock of the lathe. • A drift is used to remove the drill from the spindle.

48. The Pillar drill. The drill gauge. • This is a flat steel sheet with different sized holes and is used to measure the drill bits.

49. The Pillar Drill. Reamer. The reamer is used to finish a drilled hole. The reamer gives the exact size hole, more rounded and a better surface finish.

50. The Centre Lathe. • The lathe is used to produce cylinders and other operations such as drilling on round bars. This is known turning. • Other shapes that can be worked include square and hexagonal bar. • The lathe can work with most metals as well as polymers (plastic).