Industrial Tech Notes

Hand Tools

• Definition: Hand tools are tools powered by hand rather than by a motor.

Classification of Hand Tools (by use)

• Cutting tools: Saws, planes, chisels, knives, hatchets, hand scrapers.

  • Used to cut and shape wood.

• Drilling and boring tools: Bit brace, hand drill, auger, gimlet, auger bits, expansion bits, twist drills, countersink bits.

  • Used to make holes.

• Holding tools: Clamps, vises, cleats, wedges, straps.

  • Used to hold work pieces firmly.

• Driving (striking) tools: Hammers, mallets, screwdrivers.

  • Used to drive nails and apply force.

• Layout, measuring, and checking tools: Bench rule, zigzag rule, flexible tape, tri-square, sliding T-level.

  • Used to measure dimensions and check level and squareness.

Layout, Measuring, and Checking Tools

• Purpose: Used to set out dimensions accurately before and during woodworking.

• Common tools: Ruler, measuring tape, pencil, tri-square, dividers, template, level.

• Ruler: Measures linear distances (inches, feet, millimeters, meters). Types include bench rule, folding/zigzag rule, and flexible tape.

• Tri-square: Made of wood and/or metal; used to check squareness and flatness.

• Pencil: Soft pencil ($A1$, $B$, or $HB$) used for clear marking.

• Dividers: Two metal legs; used to mark arcs and circles. With a pencil leg, it acts as a compass.

• Template: Pattern made from tin or plywood; used to transfer shapes onto wood.

Timber Producing Trees in Guyana

• Wallaba: Long-lasting timber with high resin content; splits easily and is difficult to saw.

  • Used for electricity poles, fence poles, shingles, fuel wood, and charcoal.

  • Color is dull reddish to purplish brown with straight grain and coarse texture.

• Simarupa: Light-weight and soft timber; whitish in color; not long-lasting.

  • Used for interior finishing, cupboards, kitchen furniture, and toys.

• Hubaballi: Medium-weight, durable timber; attractive appearance; easy to work and finishes well.

  • Color is brown or reddish-brown with black streaks or bands.

  • Used for interior work and furniture.

• Dukalli: Light-weight timber; not long-lasting; fine texture with straight grain.

  • Color ranges from off-white to pale cream or pinkish.

  • Used for interior work and general manufacturing.

Conversion of Timber

1. Meaning: Conversion is the process of cutting logs into boards or planks of suitable sizes for building and furniture making. It is the first stage after felling and transportation.

2. Types of timber cuts:

   • Plane sawn

   • Quarter sawn

   • Tangential cut

3. Plane Sawn Timber

   • Advantages:

     • Quick to perform

     • Simple and economical

     • Less waste of timber

   • Disadvantages:

     • May warp or twist

     • Grain patterns may not be uniform

   • Typical uses: General construction, framing, paneling

4. Quarter Sawn Timber

   • Advantages:

     • Straight and uniform grain

     • Less likely to warp or shrink

     • Attractive appearance

   • Disadvantages:

     • More labor intensive

     • More costly

   • Typical uses: Furniture making, flooring, decorative joinery

5. Tangential Cut Timber

   • Advantages:

     • Minimizes width of planks

     • Produces attractive grain

   • Disadvantages:

     • Prone to distortion

     • Cupping during seasoning

   • Typical uses: Interior paneling, decorative applications

Note: Another word sometimes used for conversion is seasoning.

Foreign Woods

• Definition: Foreign woods are timber species imported from other countries because of special qualities such as strength, durability, color, or fine texture.

• Characteristics:

  • Durable (resistant to decay, insects, and weather)

  • Strong due to dense structure

  • Attractive appearance (rich colors and grain patterns)

  • Workability varies (some easy, some require sharp tools)

  • Usually expensive

  • Stable when properly seasoned

• Types: Mahogany, Teak, Oak

• Advantages:

  • High quality and attractive appearance

  • Long-lasting durability

  • Resistance to insects and rot

  • Unique grain patterns and colors

  • Suitable for fine and decorative work

  • High strength-to-weight ratio

• Disadvantages:

  • More expensive than local timber

  • Limited availability

  • May require special tools

  • Transportation increases carbon footprint

  • Some species are protected by conservation laws

Defects in Timber

• Group 1 (Growth Defects):

  • Twisted grain

  • Cup shake

  • Heart shake

  • Star shakes

  • Knots

• Group 2 (After Felling):

  • Shrinkage

  • Warp

  • Wane

  • Splits

• Causes of Timber Defects:

  • Conditions during tree growth

  • Method of felling

  • Storage and usage conditions

• Knots: Spots where branches once grew.

  • Sound knots: No decay

  • Unsound knots: Show decay

Electricity

• Definition: Electricity is a form of energy that flows as electric current and is used to power lights, fans, and appliances.

• Sources of Electricity:

  • Solar power

  • Batteries

  • Water (hydroelectric power)

  • Wind power

  • Fossil fuels (coal, oil, gas)

Electronic vs Electrical

• Electronic Devices:

  • Control and manipulate electricity to process information

  • Use low current

  • Contain components such as transistors and circuits

  • Examples: Phone, Tablet, Computer, Television, Microwave

• Electrical Appliances:

  • Use electricity mainly to produce energy such as heat, light, or motion

  • Use high current

  • Examples: Toaster, Fan, Light, Fridge, Air conditioner

Electrical Safety Rules

• Do not touch exposed wires

• Keep hands dry

• Switch off power before working on wires

• Switch off power after use

• Use proper tools

• Keep positive and negative terminals separate

• Do not overload sockets

• Keep electrical appliances away from water

Parts of a Simple Circuit

• Wires

• Switch

• Battery

• LED / light bulb

• Resistor

Resistor

• Definition: A resistor is a component that limits or controls the flow of electric current in