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British Standards. Graphic Communication. Department of Technological Education. Knowledge & Understanding. British Standards - Drawing Conventions Line Types Dimensioning Why? We have a greater understanding of why we are doing things in a certain way.
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British Standards Graphic Communication Department of Technological Education
Knowledge & Understanding • British Standards - Drawing Conventions • Line Types • Dimensioning • Why? • We have a greater understanding of why we are doing things in a certain way. • We have an broader understanding of the implications it has on industry.
What does British standards mean to you? • The British Standards Institution (BSI) is the UK's national standards body. • It brings together representatives from a range of organisations to develop formal Standards for the benefit of UK business and consumers.
British Standards • Standards make our lives easier, safer and healthier. Without them, everyday actions we take for granted would be unpredictable. • Standards help to make many of the products we use safer and more reliable. • Once you are familiar with the idea of products meeting Standards, it will help you to understand how Standards are met in order to keep us safe and sound.
British Standards • In Short they are set methods/procedures that allow us to consistently reproduce quality products. • With regards to Drawings BS allows standardisation ie. It creates a common language between professional people.
British Standards –Drawing • BS EN ISO 128-20:2001 - Technical drawings. General principles of presentation. Basic conventions for lines. • BS EN ISO 128-21:2001 - Technical drawings. General principles of presentation. Preparation of lines by CAD systems. • BS EN ISO 5456-2:1999 - Technical drawings. Projection methods. Orthographic representations. • BS 308-2.3:1995 -Technical drawings. Dimensioning and tolerancing. • BS ISO 128-40:2001 -Technical drawings. General principles of presentation. Basic conventions for cuts and sections.
A continuous thick line. A continuous thin line. Line Types • Visible Outlines and Edges. • Construction, projection and dimension projection. These are the two basic line thicknesses recommended in the BS. However you will see there are variations in Their use.
A broken thin line. Dashed lines should start on a line & finish on a line. Dashes and spaces should be of even length and spacing. Thin line. Long dash – short dash. Centre lines should extend slightly passed the feature it applies to. They should not stop at another line. Where centres points are defined – long dashes should cross. Line Types • Hidden outlines and edges. • Centre Lines.
Like the centre line but ends and change of direction are thick Thin line. Chain of long dash and two short dashes. Line Types • Section lines (cutting planes) • Fold lines
Solution! Section Line Fold Line Centre line
2 3 1 Arrow heads should be narrow Filled Sizes should be written Clearly ABOVE the line Projection lines should be thin and disconnected from the part. Dimensioning • When applying measurements there are some simple rules to follow!
Linear Dimensioning Parallel Dimensioning Dimensioning • Two methods we should know for now!
R10 R10 Dimensioning • For A radius… The dimension line should pass through the centre point of the arc. The dimension line should have one arrowhead that touches the arc. The symbol R is placed in front of the dimension.
Ǿ 10 Ǿ 10 Dimensioning • For a Diameter… The dimension line should pass through the centre point of the arc. The dimension line should have two arrowheads that Touch the arc. The symbol Ǿis placed in front of the dimension.
30° 30° Dimensioning • For Angles… Curved double headed arrow between lines. The angle is written outside the Arrow. Alternatively Arrows can be Outside with the angle written Lines.
Hatching for Sections • Angle used is 45° • Spacing equal 4mm • For Exploded views direction of hatching is the same. • For assembled views • Part 1 in one direction • Part 2 in the opposite direction with same spacing. • Part 3 spacing reduced to half.
Assembled Exploded Hatching for Sections
Hatching for Sections We do not Hatch… • Nuts, Bolts, washers. • Keys, Webs, Shaft. • Spindles, Gears, Pins. • Note – Shafts are only sectioned if cut through the cross sectional area.
Go for it! • BSI-Education.org/BritishStandards