Hand Tools Evolution and Use

Overview

This lecture traces the evolution of hand tools from their Stone Age origins, explains their correct use, and highlights common mistakes to avoid damage or injury.

History and Evolution of Hand Tools

• Early humans invented hand tools by fastening sticks to rocks, increasing arm strength and leverage.
• The ball-peen hammer is a modern version of the Stone Age hammer.
• Many hand tools today evolved from these primitive inventions.

Proper Use and Care of Hammers

• The ball-peen hammer is for riveting and shaping soft metal, not for crushing rocks.
• Always strike with the hammer face, not the edge.
• Use the correct hammer type for the job (brass, rawhide, plastic tip, claw, etc.).
• To pull nails, increase leverage with a wood block under the hammer head.
• Tighten a loose hammer head with a steel wedge, not by pounding on the handle.
• Grip the hammer at the end of the handle for effective blows; never use the handle as a crowbar.

Screwdrivers: Use and Maintenance

• Screwdrivers have a handle, shank, and blade; some have full-length shanks for strength.
• Never hammer on a screwdriver or use it as a pry bar.
• Match the blade width to the screw slot and ensure a good fit to avoid damage.
• Regrind chipped blades with care, avoiding overheating.
• Tapering the blade faces helps the screwdriver hold better in the screw slot.

Pliers and Their Correct Uses

• Different types include combination, diagonal cutting, long round-nose, and side cutting pliers.
• Use wire strippers and round-nose pliers for electrical work and making wire loops.
• Diagonal pliers are for cutting and removing pins.
• Pliers should not be used to tighten or loosen nuts.

Wrenches: Types and Application

• Open-end wrenches fit specific nut sizes and have a 15° angled head for tight spaces.
• Adjustable wrenches and monkey wrenches must be set for a snug fit; apply force to the stationary jaw.
• Use pipe wrenches for pipes, and wrap delicate pipes to protect finishes.
• Box wrenches grip all corners of a nut, helpful in confined spaces.
• Socket wrenches with various handles and ratchets provide leverage in many positions.

Chisels and Punches

• Use cold chisels for cutting rivet heads or rusty nuts, not hardened steel.
• Keep chisels sharp and the cutting edge slightly rounded; avoid overheating when grinding.
• Use wood chisels with the grain, and keep them sharpened and clean.
• Punches (starting, pin, and center) are used for marking and removing pins or rivets.

Saws: Selection and Care

• Use a rip saw for cuts with the grain and a crosscut saw for cuts across the grain; tooth size varies by type.
• Hold saws at recommended angles and use smooth strokes.
• Oil blades after use to prevent rust.
• Special saws include back saws, compass saws, coping saws, and hacksaws.
• Hacksaw blades must have correct teeth per inch for the material; always relieve pressure on the backstroke.

Files: Use and Upkeep

• Files are for smoothing workpieces and come in single or double cut and many shapes.
• Cut only on the forward stroke and lift on the return.
• Clean using a file card; use proper handles for safety.

General Tool Care

• Store tools in a designated place to prevent loss or damage.
• Use the correct tool for each job to avoid injury or damaging the tool.
• Regular maintenance like oiling and sharpening keeps tools effective.

Key Terms & Definitions

• Leverage — mechanical advantage gained by using a tool to amplify force.
• Ball-peen hammer — hammer with a rounded end for shaping metal and riveting.
• Slip joint pliers — pliers with an adjustable joint for different jaw openings.
• Open-end wrench — wrench with a U-shaped opening for gripping nuts/bolts.
• Box wrench — wrench with a closed loop for gripping all sides of a fastener.
• Monkey wrench — adjustable wrench for various nut sizes.
• Cold chisel — chisel for cutting metal when struck by a hammer.
• Draw filing — smoothing a surface by moving a file lengthwise.
• Try square — tool for marking or measuring right angles.

Action Items / Next Steps

• Practice correct use of each tool as demonstrated.
• Sharpen and oil tools as needed.
• Organize your tool kit so each tool has a specific place.
• Review and memorize the key terms and best practices for exam preparation.