content_image/595723.jpg content_image/595727.jpg content_image/595733.jpg content_image/595728.jpg
<img src='content_image/595723.jpg'>

<img src='content_image/595727.jpg'>

<img src='content_image/595733.jpg'>

the other; they should match. [Figure 4-144] If they do not match, adjust the end with the sharper bend back slightly. 

<img src='content_image/595728.jpg'>

## Folding a Box 

A box can be formed the same way as the U-channel described on in the previous paragraphs, but when a sheet metal part has intersecting bend radii, it is necessary to remove material to make room for the material contained in the flanges. This is done by drilling or punching holes at the intersection of the inside bend tangent lines. These holes, called relief holes and whose diameter is approximately twice the bend radius, relieve stresses in the metal as it is bent and prevent the metal from tearing. Relief holes also provide a neatly trimmed corner from which excess material may be trimmed. 

