The levelers are used primarily for leveling the frame, before the slates are put in place. When the slates are in place, the table is leveled, with a machinist grade level and shimmed, to specs + - 3-5 1000's. The slates seams are then sealed, and the cloth is installed. There are times when the levelers can be used again, if for some reason the table loses it's level at an end, slightly, and you do not want to remove the cloth, (and as long as the slate is not damaged or has become separated and unlevel at the seams, and is overall level). The table must be raised from the frame only. to raise the frame without doing any damage, you need to make a simple "Y" shaped wooden fixture, by screwing together 3 pieces of 1.5" square wood, to form the fork. The forked part is slightly wider than the frame thickness of your table, and should not be long enough to touch the bottom of the slate. The center section of the fork, ( which bears the weight of the frame) extends below the frame and rests on a small 8" bottle jack (harbor Freight). The fork and jack must be placed as close to the table leveler foot, and cross member, as possible. Put a piece of blue painters tape on the leveler foot and tape it to the floor in a straight line. Draw a line, or "Witness mark" extending from the leveler foot onto the floor, and then cut the tape in half. The line should be meeting at this cut. Now, you raise the pump jack until you barely see the leveler foot raise, but you are able to turn the leveler foot an 1/8 to a 1/4 turn. Check the slate for level. Repeat as necessary. The witness marks on the tape lets you see how far, and in what direction you went. You might want to take notes ( I'll mention here that I've done this many times on 9x4.5's and 5x 10's and there is no damage done to the table or seams, etc.) This is a hit or miss system,btw, BUT you can get pretty fair results, if the table is just off a bit, and you've run out of options