sectional views advanced drawing abilities teacher © j lewis 2004
TRANSCRIPT
Sectional ViewsAdvanced
Drawing Abilities Teacher
© J Lewis 2004
Component containing a web
A component with a bend, such as a simple bracket, can be weak at right angles to the bend so it is common to add a web or rib as shown.
The web can be triangular in shape and adds considerable strength without adding too much extra weight.
Producing sectioned views of a shape with a web follows specific rules. © J Lewis 2004
Component containing a web
Here a cutting plane, A – A, is defined and part of the component is removed.
© J Lewis 2004
Component containing a web
When a sectioned view is taken, as shown, the cut surfaces must be hatched.
© J Lewis 2004
ElevationSectional End Elevation on A - A
Component containing a web
© J Lewis 2004
Here a cutting plane, B – B, is defined and part of the component is removed.
Component containing a web
When a sectioned view is taken, as shown, the cut surfaces must be hatched.
© J Lewis 2004
Component containing a web
Here it can be seen that hatching the cut surface will give a false impression of how solid the web is, so this part is left without hatching.
© J Lewis 2004
Component containing a web
The cutting plane passes through the web as shown and is not hatched in the sectional view through C – C.
The boundary between the web and the rest of the component is drawn as a full line.
© J Lewis 2004
Assembly Drawing
In the left hand diagram, there are three parts or components.
These are, a block with a hole, a bush which fits into the hole and a shaft which fits inside the bush.
The right hand diagram shows how the three components look when they are assembled or joined together.
© J Lewis 2004
Exploded View
In order to see how the parts relate to each other and to write a set of instructions to allow someone to assemble the parts together, an exploded view is often used.
Note that each part is shown moved along the line it will follow in the assembly process.
© J Lewis 2004
Component containing a shaft
The three parts are shown as an Orthographic Assembly Drawing in 3rd angle projection.
Note that dimensions are normally required in these drawings but are omitted here for clarity.
© J Lewis 2004
Hatching a Sectional View
Note the techniques used for hatching.
© J Lewis 2004
Component containing a shaft
This is part of the convention which states that items such as shafts, nuts, bolts, washers, pins, balls, rollers and other symmetrical parts are never hatched when shown in lengthwise sectioned views.
© J Lewis 2004
Note that the shaft is not hatched in this view.