Sectional Elevations

 Used to show the insides of an object by drawing it as if it had been chopped.  Will appear in the General and Credit exams.  Read on to find out how!!!

The hidden detail lines on the elevation show the wall thickness of the flower pot. Thickness of flower pot Elevation Plan

Imagine taking a bite from a Mars Bar. What you would see is the soft bit, the caramel and the chocolate. This is what you would draw of the flower pot, what’s left after sectioning it. Mars being cut What you would see

Elevation Plan The biting or cutting line is marked on the drawing using a line like the one below. It is called a cutting plane. X X Notice the line has thicker lines at the 2 ends. Also notice the way the arrows point. This is the direction you will view the object when drawing the section. The letters XX is the name of the sectional cut

Elevation Plan X X This is how the cutting plane would appear on the drawing.

Elevation Plan X X This is what would be drawn showing the thickness of the flower pot and the back curve of the top of the pot. Sectional Elevation on XX

 Hatching is the name given to 45° lines that are used to show that a material is being cut.  The final touch to the sectional drawing is adding something called hatching.  Different materials or parts of the object are hatched using different styles of hatching.  The example below shows a pencil correctly hatched with lines in opposite directions for the lead and wooden parts. Pencil Lead Surrounding Wood

Elevation Plan X X Sectional Elevation on XX There is only one material in this example so only one direction of hatching. You should make sure there are equal spaces between your hatching lines.

 A bath plug is shown. We will be drawing a sectional elevation of the bath plug over the next few slides.

The Elevation of the bath plug is given. You have to draw the plan and the sectional end elevation on XX. X X

To draw the plan project the centre line up vertically. X X Mark on another centre line for the centre of the circle.

Use your compass to draw the outline of the plug and the top of the plug. X X The plug is circular in shape. Therefore the plan can be drawn using a compass.

These are drawn using hidden detail lines. An example of a hidden detail line is shown below. It has evenly spaced short dashes. X X The plug has the part that fits into the plug hole below the larger circle. This means that when you look at the plug from above you cannot see these parts.

As this is hidden from view it is shown as hidden detail. X X We now have to show the hole through the top part.

X X Now we will draw the sectional end elevation on XX.

X X Draw the ground line horizontally across from the elevation.

X X Draw the bounce line from the top right hand corner of the elevation.

X X Now project horizontally to the bounce line the widths on the plan. Then project them down vertically.

X X

X X Now we will project all of the heights from the elevation across horizontally.

X X Now we will darken in the outline of the sectional End Elevation on XX.

X X This is the outline of the sectional End Elevation on XX without any construction lines showing.

X X Now we need to add hatching lines to show where the material of the object is cut.

X X These areas of the sectional drawing are fresh air. This means that they are not hatched.

X X There would be a hidden detail line drawn here on a normal end elevation drawing. However, on a sectional view, hidden detail is not shown.

X X Hatch the sectional view.