The camber bar
is the metal
bar that extends across the bottom
of a truss
for at least 10 feet
. The camber bar must be made of a high-strength metal
. The camber bar is essential to truss manufacturing.
The camber bar should be centered on the table. There should be a notch cut into the top of it at the center of its length. This is important, since the trusses will be centered on this bar. Also, the bar must be straight. If you have a crooked camber bar, there's no telling if your bottom chords are straight or not, and you could end up with some really messed up trusses. The best way to make sure your bar is straight is to run a string on it. Fasten a string at the ends of the bar, making sure you pull it very tight. The string will then be straight. Compare it to the bar. If the bar doesn't follow the string, the bar is crooked and it is imperative that you get a new one.
Once you have a straight camber bar, you should pre-drill some holes in it, one every six inches or so. Then, lay the bar on the table and drill through the table wherever you have a hole in the bar. Then, fasten the bar to the table as tightly as is humanly possible with cast iron bolts. The camber bar must not move through the truss-building process! It is, perhaps, the most important item on a trussing table.