1. In the Graphic Communication exam you may well need to draw a Sectional View.
A Sectional View shows what is going on inside an object. The object is sliced along an imaginary line and part of it is removed revealing the inside of the object.
Hatching lines (not shown here) are drawn at 450 to show exactly where the cutting plane came into contact with the solid parts of the object.

2. HERE ARE SOME IMPORTANT RULES . . .
Drawing a SECTIONAL View to show information more clearly can be very helpful. Sometimes the ELEVATION, END ELEVATION and PLAN combined still do not tell the whole story of what is going on with an object. Perhaps the most interesting detail is happening inside the object.
HERE ARE SOME IMPORTANT RULES . . .
the cutting plane X-X defines where the object is to be split
surfaces touched by the cutting plane should be hatched with 450 lines
certain types of items are NEVER hatched. (you will find out which)
the arrows point at the bit that is left
DO NOT include hidden detail in a sectional drawing
In this situation, a SECTIONAL drawing is used. In a SECTION, we imagine what would happen if we sliced the object along an imaginary line and removed part of the object. When we draw what is left, the finished drawing often gives a much clearer picture of what is going on.
There are lots of rules to remember when SECTIONING and we will learn them gradually.
CUTTING PLANE LINE
PLAN X X X X
ELEVATION
SECTION X-X
CUTTING PLANE

3. Look at the two ORTHOGRAPHIC views of the block
Look at the two ORTHOGRAPHIC views of the block. You are asked to complete the SECTIONAL view X-X.
Here are a couple of PICTORIAL views of a simple engineering block. The cutting plane is clearly marked X-X. X X
PLAN X
PICTORIAL VIEWS X
SECTION X-X
ELEVATION

4. Here are a couple of PICTORIAL views of a simple engineering block
Here are a couple of PICTORIAL views of a simple engineering block. In the first view the block has been halved and in the second view the block is complete. The cutting plane is clearly marked X-X. X

5. Here are a couple of PICTORIAL views of a simple engineering block
Here are a couple of PICTORIAL views of a simple engineering block. In the first view the block has been halved and in the second view the block is complete. The cutting plane is clearly marked X-X. X X

6. Metal tubing is used for all sorts of purposes in engineering
Metal tubing is used for all sorts of purposes in engineering. Most commonly it is used as pipework to carry a wide range of liquids and gases. It can also be used to construct frameworks to support all kinds of furniture etc. and in the making of bicycles.
Sectioned metal tube

7. This small block has been manufactured to strengthen a larger framework. It was found that the large framework was much too flimsy and required to be made more rigid. Small support pieces like the one shown here were fitted to all of the joints to add rigidity.
One of the blocks is shown here sectioned.

8. The general name for a device which is used to hang things on a wall is a BRACKET. Brackets come in all shapes and sizes. The one shown here is fixed to the wall by a screw which runs through the hole in the back of the bracket. Two prongs then stick out from the wall to support whatever is required. Y X
Y – Y Section

9. A car heater control switch is shown here in various ways ; Photograph, PICTORIAL views and SECTIONS. The switch is an assembly of two parts. Exactly how they fit together is detailed in the SECTIONS.
Audi TT Dashboard B A 18
B – B Section
A – A Elevation

10. Sectional Views are used to show hidden detail more clearly
Sectional Views are used to show hidden detail more clearly. They are created by using an imaginary cutting plane to cut the object.
A sectional view shows what is left of the object after the imaginary slice has been removed. The diagram below shows a sectional view, and how a cutting plane works.

11. The example below shows a simple single plane sectional view where the object is being cut in half by the cutting plane. The cutting plane is indicated on the drawing using the line style used for centre lines, but with a thick line indicating the end of lines. The direction of the view is indicated by arrows with a reference letter. The example below shows a sectional view of the cutting plane A - A.

12. A SECTIONAL VIEW IN TWO PLANES
It is possible for the cutting plane to change directions, to minimise on the number of sectional views required to capture the necessary detail. The example below shows a pipe being cut by two parallel planes. The sketch shows where the object is cut.

13. HALF SECTIONS
Half sections are commonly used to show both the internal and outside view of symmetrical objects.

14. PART SECTIONS
It is common practice to section just a part of an object when only small areas need to be sectioned to indicate the important details. The example above shows a part sectional view to indicate a through-hole in a plate. Notice that the line indicating the end of the section is a thin continuous line.

15. HATCHING
On sectional views, solid areas should be hatched to indicate that they are solid. Hatching is drawn with a thin continuous line, equally spaced (preferably about 4mm apart, though never less than 1mm) and preferably at an angle of 45o.
HATCHING A SINGLE OBJECT
When you are hatching an object but the objects has areas that are separated, all areas of the object should be hatched in the same direction and with the same spacing.

16. HATCHING ADJECT OBJECTS
When hatching assembled parts, the direction of the hatching should ideally be reversed on adjacent parts. If more than two parts are adjacent, then the hatching should be staggered to emphasise the fact that these parts are separate.

17. HATCHING LARGE AREAS
When hatching large areas in order to aid readability, the hatching can be limited to the area near the edges of the part.

18. DRAWING THREAD PARTS
Threads are drawn with thin lines as shown in this illustration. When drawn from end-on, a threaded section is indicated by a broken circle drawn using a thin line.
A threaded part

19. DRAWING THREAD PARTS
Frequently a threaded section will need to be shown inside a part. The two illustrations to the left demonstrate two methods of drawing a threaded section.
Note the conventions. The hidden detail is drawn as a thin dashed line. The sectional view uses both thick and thin line with the hatching carrying on to the very edges of the object.