Cross-cutting on the table saw can be one of the most dangerous types of cuts you will be making while building your guitar. Most table saws come with a miter gauge for this purpose but they are inaccurate and unsafe. A better solution is a cross-cut box.
Cross-cut boxes are way safer than a miter gauge because of the long fence supporting the stock on both sides of the blade that keeps the piece in place as you cut. This greatly reduces the possibility of kick-back, and trust me, kick-back on a 3HP saw will scare the hell out of you at the very least and can result in injury.