" Axed or Pean-Hammered and Patent-Hammered.—These two vary only in the degree of smoothness of the surface which is pro duced. The number of blades in a patent hammer varies from six to twelve to the inch; and in precise specifications, the number of cuts to the inch must be stated, such as 0-cut, S-cut, 10-cut, 12-cut. The effect of axing is to cover the surface with chisel marks, which are mark parallel as far as pra-cticable. Axing is a fine finish. (Fig. 21.) " tooth-axe is practically a number of points, and leaves the surface of the stone in the same condition as fine pointing. It is usually, however, only a preparation for bush hammering, and the work is done without regard to effect, as long as the surface of the stone is sufficiently leveled.
" Bush-hamntcrcd.—The roughness of the stone is pounded off by the bush hammer, and the stone is then said to be bushed. (Fig. 22.) This kind of finish is dangerous on sandstone, as experience has shown that sandstone thus treated is very apt to scale. In dressing limestone which is to have a bush-hammered finish, the usual sequence of operations is: (1) rough-pointing, (2) tooth axing, (3) Bush-hammering.
" Rubbed.—In dressing sandstone and marble, it is very common to give the stone a plane surface at once by the use of the stone saw. Any roughnesses left by the saw are removed by rubbing with grit or sandstone. Such stones therefore have no margins, They are frequently usci in architecture for string courses, lintels, door-jams, etc., and they are also well adapted for use in facing the walls of lock-chambers and in other locations where a stone surface is liable to be rubbed by vessels or other moving bodies.
"Diamond Panels.—Soinetimes the space between the margins is sunk immediately adjoining them, and then rises gradually until the four planes form an apex at the middle of the panel. In general, such panels are called diamond panels, and the one just described (Fig. 23) is called a sunk diamond panel. When the surface of the
stone rises gradually from the inner lines of the margins to the middle of the panel, it is called a raised diamond panel. Both kinds of finish are common on bridge-quoins and similar work. The detaiLs of this method should be given in the specifications." The following classification of the surface finish for stone used in masonry is given by the American Railway Engineering Associ ation: Dressing.—The finish given to the surface of stones or concrete. Smooth.—Having surface the variations of which do not exceed inch from from the pitch line.
Fine-Poiatcd.—Ilaving irregular surface, the variations of which do not exceed inch from the pitch line.
Rough Pointed.—Ilaving irregular surface, the variations of which do not exceed inch from the pitch line.
irregular surface, the variations of which do not exceed 9 inch from the pitch line.
1?ack-Faced.—Presenting irregular projecting face, without indications of tool mark.
45. Cutting by Machinery.—In large yards and large building operations much of the shaping and dressing of stone is done by machinery. Portable machines using pneumatic tools are frequently employed, such as pneumatic hammers, drills, and chisels, which dress the stone in much the same manner as hand tools. The machines commonly employed also include saws adapted to all classes of stonecutters for rough surfacing, planers for more accu rate surfacing, and rubbing machines for grinding and polishing. The details of these machines and the character of the tools used with them vary with the nature of the stone to be worked.
In dimension stone and trimming work, drawings and dimen sions for shaping the stones are provided, and the stones are usually cut at the yard and shipped to the point of use ready to place.