Scale
Scale is used on working drawings to show objects smaller or larger than life to better communicate information and details. It is obvious that the floorplan for a house can't be drawn full sized and if it was then it would be very difficult to get any useful information from it. In the same way it will be very difficult to see the details of a very small part if it is draw at a scale of 1:1.
When a scale is used on a drawing it should always be indicated so that the 'reader' can work out how big the object will be if no dimensions are given.
Reducing Scale
If a scale is given with the first number smaller than the second then it is a reducing scale. For example, a scale of 1:2 means that every 1 mm on the page will be 2 mm in real life. This means the item will be twice as big as the drawing (the drawing will be half the size of the real object). If the scale is 1:20 then the the real item will be 20 times as big as the drawing.
Enlarging Scale
If a scale is given with the first number larger than the second then it is an enlarging scale. For example, a scale of 2:1 means that every 2 mm on the page will be 1 mm in real life. This means the drawing will be twice as big as the item.
You can work out how long lines on a drawing should be by using some simple maths.
Scaling down:
- If a 50mm line is to be drawn at a scale of 1:5 (ie 5 times smaller than its original size). The measurement 50mm is divided by 5 to give 10mm. A 10mm line is drawn.
- If a 50mm line is to be drawn at a scale of 1:2. The measurement 50mm is divided by 2 to give 25mm. A 25mm line is drawn.
Scaling up:
- If a 50mm line is to be drawn at a scale of 5:1 (ie 5 times bigger than its original size). The measurement 50mm is multiplied by 5 to give 250mm. A 250mm line is drawn.
- If a 50mm line is to be drawn at a scale of 2:1. The measurement 50mm is multiplied by 2 to give 100mm. A 100mm line is drawn.