Granite can be sawn, chiselled, and ground into shape. And it can be polished.
The first step is usually to saw the large blocks of granite into slabs. This is done with a wire which operates like a band saw except that the wire does not do the cutting itself; its purpose is to drag a gritty slurry across the granite and gradually grind a cut through it. Usually a number of these saws operate together beside each other to slice an entire block at once (like a loaf of bread). Unlike bread however, granite is so hard that this process takes many hours. Increasingly, huge diamond encrusted circular saws are being used. These can be 14 feet in diameter.
The resulting "slices" of granite are then laid flat and cut into squares of appropriate dimensions for cemetery monuments. this cutting is usually first done by using a powerful guillotine-like press to break the slabs into appropriate sized pieces. This can also be done by special circular saws looking a bit like those used in lumber mills. However, for granite, the blades have different teeth and are coated with bits of diamond to make them hard enough to cut the granite. Lons uses this type of saw for custom cutting at our Shop.
The final milling operation consists of finishing and polishing the flat faces of the granite. Wire saws leave rough, streaky lines which must be ground smooth. This is done with flat revolving grinding blocks, pads, and grit abrasives. Grinding can continue on with finer blocks and grit to produce a mirror like finish or "polish". The polished slabs are then trimmed, cut and chiselled into the shapes ordered by the monument companies. Custom or intricate shapes can be be cut, "band-saw" style, at the mill using computer controlled diamond wire saws. This is commonly the case where such cuts are to be polished. Polished edges are generally finished at the mill where the cost of the specialized equipment can be better justified.
A variety of specialized tools such as razor-sharp carbide tipped chisels and shapers, pneumatic hammers and chippers, high speed diamond cutters and grinders, and manual plus automatic sandblasting equipment are used to further carve, shape and define each individual monument. Pictured here is a craftsman doing a simple trim (called "pitching") to create a serp top.