Marking out tools, measuring tools, and gauge

Marking Out Tools

These are hand tools used for marking out the required shapes of a particular metal from the sheet metal before cutting in the metal workshop. Examples are:

(i) Surface plate: for checking the alignment and flatness of the object.

(ii) Surface table: This is used for marking out large objects, for checking accuracy, for height alignment and checking parallelism.

(v) Dot punch: This is smaller in shape and is used to mark or dot on scribed lines.

(vi) Trammel: This is used for marking out large diameter, where compass cannot serve.

(vii) Marking gauge: This is re-adjustable. It is used for marking specific lines along and across the grains of the wood.

(viii) Odd-leg caliper (Jenny’s Caliper): This is used for marking out lines parallel to an edge. It is also used for finding the centre of a round bar.

(ix) Mortise gauge: This is used for marking out two parallel lines at a time.

Measuring Tools and Gauge

These are tools used as testing and setting out tools. They are:

(i) Steel rule: Made from carbon steel, used for measuring lengths.

(ii) Folding rule: Used to measure length.

(iii) Micrometer screw gauge: Used for measuring small thickness (diameter) to a high degree of accuracy

(iv) Inside caliper: Used for measuring the internal diameter of an object.

(v) Outside caliper: Used for measuring the external diameter of an object

(vi) Vernier caliper: For measuring both internal and external dimension of an object

(vii) Centre square: For checking angles of 45⁰ and 90⁰

EVALUATION

1. State the use of the following tools: (i) Inside caliper (ii) Outside caliper (iii) Vernier caliper (iv) Odd–leg caliper