The inferior grades are narrower, with blue and black threads at the edges instead of red. The webbing should be tightly stretched and interlaced and should be nailed with seven tacks at each end. If good webbing is used, it. can generally be taken for granted that the better quality goods are used throughout. The webbing can be examined by tearing off a corner of the black cambric covering underneath the chair.
The next item to examine on an upholstered piece is the gimp which covers the tacks. This should be of good quality and well glued, firm and flat, instead of being tacked to the frame.
The stronger springs should be in the middle of the seat, the weaker in the rear and the balance in the front and sides. The best grade of springs have the ends of the springs knotted to the next loop, the inferior grades do not, the ends being merelv cut off. The advantage of the knotted spring is that it cannot unwind or get loose from its fastening and gradually slip through the upholstery material. The springs should be japanned or enamelled. They should be sewed in position to the webbing by a strong waxed twine commercially known as No. 252. This does not rot, break or fray as readily as the cheaper grades. Each spring should be tied in six places with a firm knot instead of a mere loop and they should be all tied together, each in four directions. The ends of the springs should be nailed firmly to the frame work. The springs should be covered on top with a piece of heavy burlap and each spring should be sewed to the burlap in four places. A continuous twine should be used.
The best hair is "South American Drawings," which is long and soft horse hair that has been sterilized, treated and curled, either black or white in color. The white is slightly more expensive but no better in quality. There should, however, be no short pieces mixed in. The hair is placed on top of the burlap which covers the springs, and under the cross stitchings of twine, the hair is worked and interlaced by the experienced upholsterer. Over this is loosely tacked a piece of light burlap, which in turn is sewn to the under heavy burlap. This is done by means of a series of squares covering the whole scat or back. After this is completed, additional hair is worked in, and then the top piece of light burlap is tacked tightly down to the frame with tacks about 1/4" apart.
The edgings are now shaped and the edge stitching made, under which is placed a thin layer of hair, and over this is placed unbleached material, firmly stretched and tacked on the sides. Over this is placed a layer of cotton wadding, and finally the finished material, which is tacked closely to the moulding.