Y8 Tech first term (combined).txt

• 1. Don't let SLEEVES, ties, hair etc hang loose
• 2. Wear protective GOGGLES
• 3. Wear protective SHOES
• 4. Wear protective GLOVES

You're wearing GOGGLES to protect your eyes.

• 1. ensure that your work is in a VICE
• 2. ensure that machine GUARDS are properly in place
• 3. ensure that cutting tools are SHARP and are set correctly
• 3. ensure you know where the STOP button is

• 1. keep your hands away from MOVING PARTS
• 2. ensure GOGGLES are covering your eyes
• 3. keep your hands away from the CUTTIN EDGE

• 1. never RUN
• 2. get PERMISSION to use a machine
• 3. if you have any DOUBTS, ask teacher

Ensure that you are wearing GLOVES or BARRIER CREAM.

It's a COPING SAW

It's used for cutting out intricate shapes and patterns and has a very thin blade.

A HEGNERSAW or SCROLL SAW.

It's a motorised version of the Fret Saw. It's used for cutting intricate shapes in wood and can cut wood up to 25mm thick. It is a very dangerous machine to use!

A BANDFACER.

It's used for sanding (smoothing) wood surfaces.

A VICE, or vice-grip.

It's used for holding things tightly in place.

A try square.

It's used for marking and measuring a piece of wood.

The square allows you to accurately measure a right angle (90 degrees).

It's a G shaped device used for tightening two pieces of wood together to make the glue set properly.

• Nails are normally made form mild steel.
• Three types:
• ROUND WIRE - for cheap constuction work
• OVAL WIRE - for better quality work
• PANEL PIN - for fixing thin sheet material

The heads in Oval nails can be hammered in below the surface, whereas the heads of Roundwire nails cannot.

To punch nails in below the surface.

Poly vinyl acetate.

It's a white creamy glue and is the most commonly used type of glue.

Because it's very difficult to remove once it's set (after about 4 hours).

Waterproof and non-waterproof PVA

• 1. hold one piece securely in a vice
• 2. get the nails started in the other piece of wood
• 3. put a THIN LAYER of glue on both touching surfaces
• 4. position and hammer in the nails
• 5. wipe off any excess glue

• Hardwood - comes from broad-leaf decidious trees eg OAK, ELM
• Softwood - comes from conifer trees.
• Manufactured - from factories!

• plywood
• blockboard
• chipboard
• hardboard

Plywood is made by sticking "veneers" together.

It's used for toys and the bottoms of drawers.

Blockboard is made by sticking many thin layers of softwood side by side, then sticking a thin veneer on each side.

It is used for making modern furniture.

Chipboard is made by gluing thousands of tiny bits of wood.

It is used with a front veneer for kitchen cupboards.

Hardboard is made by gluing and compressing pulped wood.

It is used for large areas like the backs of cupboards.

• Mahogany hardwood - used for high quality furniture
• Beech hardwood - used for workbenches.

• Redwood - honey colour - house roofs and window frames
• Parana pine - pale yellow - staircases.

To clear out water from the tree.

By counting it's annual rings.

• Ferrous metals contain iron
• Non-ferrous metals do not contain iron

Mild Steel - tough - used in school workshops, car bodies, nuts and bolts

Carbon Steel - tough - cutting steel e.g. drillbits

Stainless Steel - tough - cutlery. medical instruments

Cast iron - strong but brittle - castings, car engines, manhole covers

Wrought iron - tough, resists rustic - gates and railings

Aluminium alloy - ductile, very light - window frames, aircraft, kitchenware

Copper - ductile, can be beaten into shape - electrical wiring, tubing, kettles

Brass - hard, conducts electricity - electrical fittings, ornaments

Silver - ductile, resists corrossion - jewellery, solder and ornaments

Lead - soft, heavy, ductile - solders, pipes, batteries, roofing

• It means that they are one after each other in a straight line.
• The current going through both is the same as the current being supplied by the battery.

In parallel means that they appear in a parallel in a circuit.

If three lights were in parallel, the current going though them would be 1/3rd of the current being supplied by the battery.

In series (current is the same throughout).

• In parallel.
• Here, the current from the battery gets split into three. Each of the lights gets the same current through it, but this current is only 1/3rd of the current a bulb in a series circuit would get.

• 
• It MAKES the circuit when pressed down.

• 
• when pushed it BREAKS the circuit

• 
• when a magnet comes near, the reed wires are forced together to make the circuit.

• 
• another name is : SPST switch
• (single pole, single throw)

• another name is SPDT switch.
• (single pole, double throw)

Light Emitting Diode

To put a resistor in front of it in the circuit. This is because LEDs only need a tiny amount of current (max 30mA) and the resistor will dramatically reduce the current going into the LED so it doesn't burn out. LEDs typically operate between 10-20mA of current.

• Anode - negative (think of anti)
• Cathode - positive (this leg is longer than the anode)

1.5 volts up to 5 volts

The negative ANODE should be connected to the POSTIVE BATTERY terminal.

The positive CATHODE should be connected to the NEGATIVE BATTERY terminal.

• Voltage - volts
• Current - amps (or milliamps)
• Resitance - ohms

A thyristor is an electronic component that can be used to create a latching circuit. It is a semi-conductor.

When 0.7V is received at the gate, the thyristor is said to be "latched" (or "remembered").

When the latch is triggered it remains on until a signal is received. This means that they are very useful in alarm circuits.

• Anode
• Cathode
• Gate