Essential Metalworking Techniques and Tool Usage
Fundamentals of Metals and Metallurgy
Metal Properties and States
Solid elements are metals at room temperature, except mercury, which is liquid.
Metallurgy is the set of processes and techniques involved in the production of metals and alloys.
Key mechanical properties include:
- Hardness
- Elasticity
- Tenacity
- Malleability
- Ductility
- Mechanical Strength
Classification of Metals
- Ferrous metals: Are those containing iron.
- Non-ferrous metals: Do not contain iron.
Basic Metalworking Operations and Tools
Tracing and Layout Operations
The tracing operation aims to draw lines or stroke contours to delimit the metal pieces intended for construction.
Tracing Instruments (Active)
Active tracing instruments are used to mark the lines or strokes.
Auxiliary and Support Instruments
- Auxiliary instruments: Support the pieces being outlined and serve to guide the lines drawn on the pieces.
- Brackets: Instruments that hold or clamp the pieces being traced.
Examples of support tools include: Marbles (surface plates), support brackets, blocks, V-shaped wedges, guidelines, and rules.
Instrument Maintenance Tips
- Do not use the basis for tracing instruments when chipping pieces.
- Keep tracing instruments slightly greased to prevent rust.
Clamping Tools and Techniques
The Vise (Clamp)
- The vise should be at the operator’s elbow height.
- When the job is finished, do not leave the jaws tight.
Clamps (Sergeants)
- Clamps should always be kept clean and lightly greased.
Pliers and Tongs
Pliers are universal multi-purpose tools used for clamping and cutting functions.
- Flat-mouth pliers: Have flat insides and are utilized for holding flat sheets.
- Round-mouth pliers: Have mouths formed by two conical parts and are used to bend wire into a circular shape.
- Adjustable grip pliers: Allow the regular opening of their mouth by turning a screw.
- Adjustable tongs: Used to hold various tubes.
- Locking pliers (claws): Quick adjustment tools with locking mechanisms for holding different types of pieces.
Safety tip: Do not ever put your fingers between the handles.
Metal Cutting Operations
Metal cutting can be done with material detachment (sawing) or without material detachment (shearing).
Hacksaws (serrated arches) are used for cutting metal.
Shearing Tools
Shearing consists of cutting the material between two sharp blades that slide past each other.
- Snips (Scissors): Scissor-like tools with two sharp steel blades and handles, joined by an axis around which they pivot.
- Cutting pliers: Instruments formed by two identical metal parts finished in cutting edges (cutting jaws), articulated by a pin that separates the handle from the cutting jaws.
Cutting Safety and Maintenance
- When cutting with snips, mark the cutting path previously.
- Cutting blades should be kept perfectly clean and sharp.
Filing Operations
Filing of metal is intended to reduce, polish, or touch up the pieces.
Filing Technique and Maintenance
- When files become clogged, they should be cleaned with a file card.
- Do not touch the surface of the piece or the files with your hands.
Striking and Percussion
The percussion operation (striking metal parts to warp or bend) is performed using hammers and mallets.
Types of Hammers
Hammers for working metals come in highly variable shapes and sizes. Examples include:
- Peening hammer
- Ball-peen hammer
- Nylon mallet
Sheet Metal Bending (Forming)
Sheet metal bending is the process used to shape thin sheet metal parts.
Bending Techniques and Safety
- Bending is performed by hitting the sheet metal with a nylon hammer on a block of wood to avoid damaging the metal surface.
- The edges of the plate must be filed (deburred) to prevent cuts.
- Use gloves when manipulating metal pieces to prevent cuts.