METAL WORK- HAND TOOL-Marking out and measuring tools
SUBJECT: BASIC TECHNOLOGY
TERM: 3RD TERM
TOPIC: METAL WORK- HAND TOOL-Marking out and measuring tools
Metal is one of the materials used in technology for construction and fabrication of devices. Metal as a material can be fabricated into various shapes and products. However, to be able to do that, you need appropriate tools. These tools are either hand tools or machine tools.
MARKING OUT TOOLS:
Marking out tools are hand tools used for making lines on metal surfaces, checking alignment, and indicating points or positions on a work piece.
Tools for making out in the workshop include:
The surface plate is a precision piece of equipment with a flat surface of high-grade finish, on which work piece are placed for marking out. It is also used for testing the flatness of surfaces.
Care of surface
The surface or marking out table is larger than the surface plate. It is used for supporting bigger work piece, so that marking out can be carried out with ease and accuracy. It is made up of cats iron and has a high grade surface.
The scriber is the metal worker’s pencil. It is used for marking out lines by hand and together with straight edges like steel rules, try squares or box rules. It is made from high carbon steel or stainless steel, hardened and tempered. They are of various sizes.
Dividers are two-legged steel instrument used for scribing arcs, curves and for setting off distances. Dividers are available in various sizes, and may be available in various sizes, and maybe spring-loaded with a fine adjusting screw or may be firmly joined at the head.
This is either a medium or high carbon steel material. We have dot punch and the centre punch.
Dot Punch: This is used for denting scribed lines. This is done some space apart; to make the lines indelible while one is working. It is 600 at its conical end.
Centre Punch: It is used for providing a heavy conical dent at the end point where a hole will be drilled in a work piece. This prevents the drill from deviating from the current location of the hole. It is 900 at its conical end.
Try square: The try square is used for testing the squareness of surface, and marking out lines at right angles to given edges. It is a high precision tool that should be handled with care. The stock and the blade, which are the main parts, make 900 with each other
Box Square: The box square is used for the making parallel lines on a round bar, It is made from medium carbon steel (hardened and tempered) and has graduations on its body to facilitate marking off dimensions, while marking out
Measuring tools are tools of measuring lengths, widths, thicknesses, or sizes of metals. Measuring is usually done during marking out.
Common measuring tools include the following:
The steel rule is made of carbon steel or stainless steel. It is graduated in millimeters and centimeters. To take a measurement with it, the steel rule should be placed on its edge to touch the work, so that an accurate reading can be taken from the centre of the division lines.
Calipers are used for measuring diameters, width, and thickness of objects.
The combination set, as the name implies, is a measuring instrument, which consists of three heads:
It is used for taking precision measurements. We have both internal and external micrometer, which are used for measuring diameter of small objects in millimeter.
It is used for both external and internal precision (accurate) measurements of objects in centimeter.
It is used for measuring the depth of holes similar to that of an outside micrometer.
It is used to perform two functions namely:
Read about MORE ON HAND TOOLS.
NERDC- BASIC TECHNOLOGY BOOK 1, page
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