LOCATING AND SETTING OUT PROFESSIONAL ENGLISH IN USE FOR ENGINEERING

 

PROFESSIONAL ENGLISH IN USE FOR ENGINEERING UNIT 5. LOCATING AND SETTING OUT

 

A Centrelines and offsets The drawing below shows the position of some holes and bolts. The distances between the holes can be shown as running dimensions or as chain dimensions. In both cases, the centreline (CL) – a line through the centre of the hole – is marked (drawn), and the distances between the centrelines are given. Distances between centrelines are called centre-to-centre (c/c) dimensions. The holes below are at 100 mm centres. B Grids In large designs, notably those of structures, grids are used for horizontal positioning. The gridlines have numbers and letters. All numbered gridlines are parallel with one another – that is, they are straight, and are regular distances apart. Lettered lines also run parallel with one another, and are perpendicular to (at a right-angle to) the numbered lines. EXERCISES 5.1 Look at the sentences about the design of a ship. Replace the underlined words and expressions with alternative words and expressions from A opposite. 1. The handrail is fixed by 115 brackets, which are 175 mm apart, between their centres. 2. The dimensions are measured from the line down the middle of the ship. 5.2 Look at the extracts from technical discussions on a construction site. Complete the sentences using the words in the box. Look at B opposite to help you. gridline intersect parallel perpendicular set out square off   1. According to the drawing, ____________ B runs along the external wall of the structure. 2. The positions were marked accurately – they were ____________ by our site engineer. 5.3 Match the two parts of the sentences to complete the extract from a training manual. Look at A and B opposite to help you.

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