What the bolt circle page calculates
The fetched Omni bolt circle calculator locates the centers of equally spaced holes around a circular pattern. That output is useful for CNC drilling, CAD work, robotic drilling, and shop-floor layout.
Bolt pattern equations
R = D / 2
B = 360 / n
x_i = cos((i - 1) x B + A) x R + x_c
y_i = sin((i - 1) x B + A) x R + y_c
Worked example from Omni
Omni's example uses a 100 mm diameter bolt circle with 5 holes, a first-hole angle of 0 degrees, and center offset (0, 0). The resulting points begin at (50, 0) and then advance every 72 degrees around the pattern.