SLAB - Cutter
Slab cutters are instruments to cut clay into slices of different heights. Home-made ones are good for working with small quantities. Each side is built up with pairs of narrow planks of wood that can be the same or of different heights. Each has a hole at one end and is slipped over the metal pole, this allows them to be turned outwards so the walls are at the height you need. Clay is put between the two walls; it must be higher than they are. To cut a wire cutter is held at the back firmly on top of the wood and is pulled through the clay. Then the bars at the side are turned outwards to the height you want to cut the slab. You cut again in the same way and you have your slab.
The first drawing shows a handmade slab cutter and the second is a close up of how the metal bar is attached under the floor. For large quantities, industrially made ones should be used.