Truss & Rigging

You know you have to use grade 8 bolts to put that truss together - but how do you tell which bolts are grade 8?
Check out the Bolt & Nut Grade Markings graphic.

Truss Circles

If you're staring at a section of circle truss, it's difficult to tell what its radius is - or what diameter circle it's part of - without assembling half the circle. Assuming you don't have the time or space to set it up, you'll need a little math.

(circle OD in feet × 12inches × Π ) ÷ sections in circle = arc length

Now you know the measurement along the outside curve for the circle piece you're looking for. This will also help you figure out the length of scenic borders, cable, ropelight, etc. to be run along the curve of the truss. If you've entered the inside diameter of the circle, you'll get the inside arc length. The chord measurement may be easier to use, since you don't have to get your tape to ride the curve - just measure from point to point.