=61. Determination of Size of Sash or Frame Pulleys.=—The architect’s specifications should stipulate the diameter of the sash pulleys to be used in the work, and this item requires careful consideration. Where care is not exercised in this regard, either the pulleys will be so small that the weight will rub against the pulley stile, or they will be so large that the weight will rub the jamb casing on the opposite side of the pocket. Standard sash pulleys are made in sizes from 1¾ to 3 inches in diameter, varying by quarter inches. In determining the diameter of the pulley required for a particular window frame, a good rule is to multiply the thickness of the pulley stile by 2.25; thus, a ⅞-inch stile would require a 2-inch pulley; a 1⅛-inch stile, a 2½-inch pulley; and a 1⅜-inch stile, a 3-inch pulley. It is best to specify that pulleys for metallic frames shall be of the larger size, namely, 3 inches in diameter; and also that these pulleys shall have ⅜-inch axles. =62. Sash Cords and Chains.=—The =sash cords= by which the sashes are attached to the counterweights in double-hung windows are usually furnished by the carpenter, and are so specified. However, they may be specified under hardware. The specification for the sash cord should state both the size and the maker’s name, and for good standard work _Sansom Spot_ or _Silver Lake_ sash cords are the best that can be procured. Table VI will be found convenient in determining the diameter of the cord and the consequent size by number, as well as the size of the sash pulley. TABLE VI STANDARD SIZE OF SASH CORD FOR PULLEYS ----+--------+---------+---------+---------+--------- | | Average | | | Size|Diameter| Weight | Average | Heaviest| Smallest No. | of Cord|per Dozen|Number of|Weight to|Pulley to | Inch | Hanks | Feet per| Be Used | Be Used | | Pounds | Pound | Pounds | Inches ----+--------+---------+---------+---------+--------- 6 | ³/₁₆ | 18 | 66 | 5 | 1½ 7 | ⁷/₃₂ | 22 | 55 | 15 | 1¾ 8 | ¼ | 27 | 44 | 25 | 2 9 | ⁹/₃₂ | 33 | 36 | 35 | 2¼ 10 | ⁵/₁₆ | 44 | 27 | 45 | 2½ 12 | ⅜ | 60 | 20 | 55 | 3 ====+========+=========+=========+=========+=========