Saw Blade Types and Features

Blade Types

• Flexible blades feature hard teeth, making them virtually unbreakable, ideal for inexperienced users or awkward sawing positions.
• Bimetallic blades consist of a high-speed steel cutting strip joined to a flexible alloy-steel back, offering durability and fast-cutting capabilities with shatterproof properties.

Cold Chisels

• Cold chisels, made from high-carbon steel, are hardened and tempered at the cutting end for optimal performance.
• The striking end remains untempered to absorb hammer blows without chipping.

Classification of Cold Chisels

• Flat Cold Chisel:
  • Has a broad flat point for cutting thin sheet metal, removing rivet heads, or splitting corroded nuts.
  • Ground to an angle of approximately 60 degrees.
• Cross-Cut Cold Chisel:
  • Features a narrower point for cutting keyways, narrow grooves, and small holes in sheet metal.

Using Cold Chisels

• Proper support is essential when using a cold chisel to prevent distorting the metal.
• Small sheets should be held in a vice, while larger sheets can be supported with two clamped metal bars.

Safety at the Workplace

• Workplace safety is crucial due to the various hazards that can cause serious injuries.
• Emphasis on the need for better safety practices is highlighted as change has been slow.

ISO Metric Thread

• Based on a 60° triangular form, offers coarse and fine pitches.
• Designated by "M" followed by diameter and pitch in millimeters (e.g., M16 × 2.0). Absence of pitch indicates a coarse thread.

Locking Devices

• Systems to prevent bolt loosening include:
  • Self-locking screws and bolts
  • Locking nuts
  • Locking washers
  • Circlips

Riveting

• Riveting is favored for its speed, simplicity, and low cost for fastening, particularly in permanent joints.
• Light riveting utilizes high-speed machines for efficiency, especially on assemblies that do not require regular disassembly.

Types of Rivets

• Rivets are available in materials such as steel, brass, copper, and aluminum.
• Solid Rivets: Strong and require substantial force to form the end (clinching); used in applications where high forces won't damage materials.
• Tubular Rivets: Designed for applications needing lighter clinching forces, offering the advantages of solid rivets with easier forming capabilities.