Abstract: A system of precision, precut joints developed for tubular-framed, modular furniture enabling a user to assemble furniture pieces quickly and easily with the use of ordinary hand tools. In the primary joint of this system, a truncated corner of a horizontal panel or shelf is fastened to a vertically-disposed, grooved section of tubing. Receiving the corner is a groove which is cut in the tubing section transversely to the longitudinal centerline thereof and which has a height slightly greater than the thickness of the shelf or panel. Opposite the groove and midway between opposing distal ends of the groove, the section has a first hole formed therein for receiving a screw threadedly engageable with a second hole formed in the truncated corner. As the screw is tightened, it pulls the truncated corner into the groove, forming a strong joint.