What is a bolt circle?

What is a bolt circle?

• A. A circle that passes through the centers of a set of equally spaced holes or fasteners in a pattern.
• B. A circle that bounds the outer edge of a bolt pattern.
• C. The diameter of a single bolt hole.
• D. A circle used to locate the pattern’s origin.

Answer: (A)

The bolt circle is the circle on which the centers of all holes in a bolt pattern lie. When holes are evenly spaced around a circle, you can imagine a circle that passes through all those hole centers; the diameter of that circle is the bolt circle diameter. This concept defines how the holes are arranged and is used to align mating parts. It’s not the outer edge of the pattern, nor the diameter of a single hole, and it isn’t just a circle used to locate the pattern’s origin.

The bolt circle is the circle on which the centers of all holes in a bolt pattern lie. When holes are evenly spaced around a circle, you can imagine a circle that passes through all those hole centers; the diameter of that circle is the bolt circle diameter. This concept defines how the holes are arranged and is used to align mating parts. It’s not the outer edge of the pattern, nor the diameter of a single hole, and it isn’t just a circle used to locate the pattern’s origin.