Place a 30-by-48-inch restaurant tabletop upside down on the ground or on a work surface. Flip two bar stools over and place their seats on the table, centered at either end. The stools should be the same height and have flat seats that do not have a cushion.
Use a permanent marker to outline the seats onto the bottom of the tabletop.
Center a bolt-down top plate from a restaurant table base on top of the seats of the stools. Use a permanent marker to outline the center hole of the top plate.
Drill a 1/2-inch pilot hole in the center of each stool at the location you previously marked.
Center the top plates on the bottom of the tabletop in the middle of the shapes you outlined with the marker. Use the marker to indicate the location of the four larger holes in the corners of each top plate.
Drill a 1/2-inch pilot hole into the bottom of the tabletop at the locations you just marked.
Secure the center of each top plate to the seat of the stool by using a 1/2-inch flange bolt. Use the pilot holes you already made to assist you.
Place flange bolts in the openings at the corners of the top plates. When the stool is standing upright, the ends of the flange bolts should point upward. Use a piece of masking tape to hold the head of the bolts in place so they are in position.
Turn a stool upside down and align the ends of the bolts with the pilot holes drilled into the underside of the tabletop.
Use the flange bolts and a ratcheting wrench to secure the stool to the table.
Attach the second stool to the other side of the table using the same process.