Half And Broken-Out Sections In Technical Drawings

Technical drawings are a very important tool between the people that deal with the same professional area such as mechanics. Technical drawings are the main connection and communication language between technicals. So, technical drawings must be in such standards which are defined by ASME or other global standardization institutions. 

Sectioning is the widely used technique to show the internal structures of parts and assemblies. There are lots of standards about sectionings and section lines in technical drawings. A technical drawing creator must obey these rules. 

Technical Drawing with Engineering Graphics

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Half and broken-out sections are two section lining techniques that are mainly used commonly. Let’s look at in which cases that half and broken-out sections are used in technical drawings. 

Half Section Technique In Technical Drawing

Half section technique(Image Source: transport.itu.edu.tr).

The half section technique is useful for the symmetrical parts in which both external and internal geometric features are shown. Half section technique is used by removing a quarter of the symmetrical part with a section plane and showing this section with hatch lines. 

Features such as detailed dimensions, tolerances and production directives are not shown in general. It is hard to show hidden and dimension lines in half-sectioned parts. 

In assembly drawings, the half-section technique is very useful o show both internal and external features. 

Broken-Out Sections

Broken-out Section Examples
Broken-out Section Example ( İmage Source : SolidWorks Community)

In such cases of assembly drawings, it can be very useful to show broken-out sections. If a detail of a very small section of a part must be shown, it is broken with a line and shown as a section to show the required internal geometry. 

As we stated above, these techniques are not used in main technical drawings of single parts in which all the details are shown. These section techniques are generally used on particular parts of assembly drawings. 


As you see above, it is very useful and simple to show required details of parts in technical drawings with the half and broken-out section techniques.

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