A block of marble, granite or limestone leaves the quarry as a rough, heavy piece of stone that can weigh many tons. Before it becomes a slab, a column, a stair or a sculpture, it has to be squared, cut and shaped. Every decision made at this stage decides how much usable stone comes out of the block and how much ends up as waste.
The first step is to square the block so that it sits steadily and its faces are parallel. Then it is cut into slabs, usually with a gang saw or a wire saw, to produce tiles and countertops. When one large piece is needed, such as the base of a monument, a thick step or a window frame, it is cut straight from the block with a bridge saw. Here a steady blade, a rigid bridge and plenty of cooling water matter more than raw speed. A blade that wanders off its line leaves an uneven cut, and every face loses a few millimetres of stone.
In block work, waste is money. The block should be inspected before cutting for natural veins and hidden cracks, and the cutting plan should be marked on it so that the best-looking section ends up where the customer will see it. When the cut is planned on screen first and then carried out by a CNC machine, the dimensions repeat exactly every time, which saves both stone and the time spent on trimming and polishing afterwards.
Carving stone used to mean weeks of hand work. Today a 5-axis CNC machine tilts and rotates the blade or the tool, so it can cut bevels, arcs, fluted columns, balusters and curved stair stringers directly from the block. The machine follows a 3D drawing, so the second and third piece come out identical to the first. Hand finishing still has its place in artistic work, but the rough shaping, which is most of the effort, is done by the machine.
Four things are worth checking. The first is the rigidity of the structure, because vibration shows up on the stone. The second is the size of the table and its load capacity, matched to the blocks you actually handle. The third is the number of axes and the working range, which decide which shapes you can make. The fourth is the software that links the drawing to the cutting path. Service close by matters as much as the specification, because a machine that waits two weeks for a spare part costs real money.
If you work with stone blocks and want to see what a CNC bridge saw could do in your workshop, get in touch. We represent Italian Donatoni in Israel and will gladly arrange a demonstration of the machines.
