The size is to create on the glass object linear patterns, geometric, flat ribs, facets, bevels, olives, diamonds, festoons, curves, by digging the glass using grinding wheels different templates to get a decor or create a new shape. The wheels are fixed on horizontal lathes driven by a motor. The first step is the “Compassing” (which is not obligatory): with the help of precise technical sketches, landmarks and lines are written in the felt pen on the object. Carefully defined, these grids are the only reference when setting the trim. To dig the crystal, the tailor exerts pressure on his piece by presenting it in front of a diamond wheel. The work is constantly done under a trickle of water, to facilitate the size and avoid the explosion of the crystal overheated by friction. In some cases, a second rubber grinding wheel and pumice will restore transparency (polishing) back into the patterns. For shine (polishing) it is necessary to make another pass with a grinding wheel of felt and cerium oxide.