METAL WORK- HAND TOOL – CUTTING AND DRIVING TOOLS
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CUTTING TOOLS
Cutting tools are tools used for cutting materials by either sawing, filing, chiseling, scraping.
Cutting tools include the following:
- Hacksaw
- Files
- Chisel
- Scraper
- Hacksaw
The hacksaw consists of two parts: the frame and the blade. It is used mainly for cutting metals in the metal workshop. We have (i) the adjustable hacksaw (accommodates different blades) (ii) tubular hacksaw (It has fixed frame) (iii) junior hacksaw (For cutting thin sheets)
- Files
Files are used in forming metals to shape, by the principle of bit-by-bit removal. Files are used for finishing jobs to the required sizes and shapes, after they have been previously cut, using either a chisel or a hacksaw. Files are commonly made from high carbon steel (hardened and tempered). Their length, cross sectionals, shapes, grade, areas of cut and the nature of their cutting teeth, classifies files.
Grade selection
- Rough grade: Used for heavy cuts.
- Bastard grade: Used for medium cuts.
- Second grade: Used for light cuts.
- Smooth grade: Used for finish cuts.
- Dead smooth cut: Used for light grade finish cuts.
Types
- Flat file: Used to obtain flat surfaces.
- Hand file: Used to obtain flat surfaces.
- Round file: Used for forming small radii, and for opening out round holes.
- Half-round file: Used for filing curves of all shapes. It is usually double cut.
- Triangular file: Used for forming dovetail joints to shape and open up triangular holes and awkward corner.
- Knife-edge file: Used for forming small V-grooves to shape.
- Square file: Used for filing rectangular hole, narrow slots ad grooves, and for the finishing of square edges.
Methods of filing
- Across and from left to right
- Across and from right to left
- Draw filing
Evaluation
- State 3 key points about the use of chisel.
- Mention 7 types of chisel and their uses
- Chisel
Chisels are mainly chipping tools used for shaping metals, where finishing by other means, such as filing, cannot be carried out. Chisels are made from high carbon steel (hardened and tempered)
Types of chisel
Flat chisel: Used for general work such as:
- Leveling metal surfaces
- Removing rivets, screws and bolt heads
- Rough-cutting sheet metals, and
- Cutting off excess metal after drilling
Cross-cut chisel: Used for:
- Cutting keyways on shafts and in holes
- Cutting spines and
- Cutting slots
Round-nose chisel: Used for:
- Cutting oil grooves in bearings and
- Cutting V-shaped grooves.
Diamond point Chisel: Used for:
- Cutting Vee grooves, and
- Cutting oil wells bearings:
Evaluation
- State 5 key points about the use of chisel.
- Mention 4 types of chisel and their uses
- Scraper
Scrapers are used for removing imperfection from a surface that has been previously worked on. Scrapers are made from medium carbon steel (hardened and tempered)
Flat scraper: Used for making a surface accurately flat, after it has either been machined or filed. It requires high-level skill to use
Half-round scraper: Used for removing high spots on curved surfaces such as holes, bearings and large bores.
Triangular scraper: Used in awkward corners, where the use of the other scrapers proves difficult
Evaluation
- Outline the procedure for carrying out scraping work
- Mention 3 types of scraper and their uses
- DRIVING TOOLS
Driving tools are tools used for moving objects into metals through hammering, punching, or screw driving.
Driving tools are tools include the following:
- Hammers
- Punches
- Screwdrivers
HAMMERS
Hammers are the most commonly used of all tools. They consist of a metal head and a wooden handle.
Types of hammer
- Ball Pein Hammer: Used for riveting conical end rivets, while the other flat end is for striking.
- Cross Pein Hammer: Used for riveting in awkward places and flat end used for striking
- Straight Pein Hammer: Used for riveting in Vee-grooves.
- Special Hammers (Mallets): Used when steel head may be too strong for the job. They are made of lead, copper, rawhide, wood, plastic or rubber. They are called Mallet
PUNCHES
Punches are driving tools. They are used for punching holes in steel metal, driving out rivets, tapered pins or dowels from holes.
- Pin Punches: They are used for driving dowel pins, and holding shafts and lubs together.
- Round Punches: They are useful when a round sleeve or shaft has to be removed from a hole
- Square Punches: They are useful where a square bar sleeve has to be removed from a hole in which it is. It must be noted that all punches are aided by hammer strikes to achieve their goal.
SCREWDRIVERS
Screwdrivers are used for fixing or removing screws by their heads. This is done using the blade of the screwdriver. Screwdrivers are made from carbon steel (hardened and tempered)
Types of screwdriver
- Flat screwdrivers
- Star screwdrivers
- Ratchet screwdrivers
- Allen key
General Evaluation
- Define driving tools
- State 8 driving tools and their uses.
- State 3 examples of screwdriver
WEEKEND ASSIGNMENT
- Which of the following is not a cutting tool? (a) File (b) Chisel (c) Ceramic (d) Hacksaw
- One of the following is used for removing imperfection from a surface that has been previously worked on. (a) Hammer (b) Chisel (c) Scraper (d) Hacksaw
- The following are examples of driving tools except ___(a) hammer (b) screwdriver (c) caliper (d) punch
- Which of the following is not a grade of file? (a) Rough grade (b) Bastard grade (c) Second grade (d) fine grade
- Which of the following hammer is used for riveting in awkward places and flat end used for striking to determine the centre of round shafts and holes? (a) Ball Pein hammer (b) Cross Pein hammer (c) Straight Pein hammer (d) Special hammer
THEORY
- Define the following hand tools (i) Cutting tools (ii) Driving tools
- State (i) 4 Cutting tools (ii) 3 Driving tools
See also