A combination square without a protractor head is primarily used to layout what kind of lines?

A combination square without a protractor head is primarily used to layout 45-degree lines. This tool is essential for accurately marking or measuring angles, particularly the 45-degree angle, which is crucial in various facets of ironworking, such as frame assembly and layout work.

The square's design typically includes a ruler and a 90-degree angle, allowing for straightforward layout of perpendicular lines as well. However, when the protractor head is absent, the main functionality focuses on achieving consistent and exact 45-degree angles, which are frequently utilized in cuts and joints, ensuring proper alignment and fit in structural projects. This skill is vital for ensuring the integrity and aesthetics of the finished work.

Understanding the role of the combination square in achieving these angles helps underscores its essential function within the trade, especially for tasks that require precise positioning and assembly of materials.