SMALL DIMENSION MACHINERY In selecting machinery for the manufacture of small dimension stock the operator should remember that appearances mean little, and that a coat of paint may hide a multitude of defects. The fol FIGURE 9.-Cut-off saw teeth. A shows a good type of tooth with correctly lowing is a summary of the points which should be considered in selecting cut-off saws, ripsaws, planers, and other equipment. Cut-off saws and tables.-The old type of overhead swing cut-off saws are heavy, awkward to handle, and inaccurate. In comparison the modern, straight-line cut-off saws are light, easily worked, efficient, and accurate. Each saw should be equipped with a caststeel table of approved design. Ball-bearing rollers on the infeed table expedite the movement of stock, and a slight backward tilt makes the stock fall easily into position. The outfeed table is equipped with a series of automatic end stops which are placed on a graduated bar. A kicking mechanism, operated by the saw carriage, may kick the cut stock onto a conveyor belt running parallel to the saw table. A series of three or more conveyors, one from each saw, may discharge the stock onto one lateral belt, from which the necessary number of helpers remove the stock and pile it on various factory trucks. Ripsaws.-The new chain-feed, straight-line ripsaw has as many advantages over the old hand-feed types as has the modern cut-off saw over antiquated models. It is estimated that the modern ripsaw will effect a saving of 5 per cent over the hand-feed type because of its ability to make perfectly straight cuts and to eliminate defects with a minimum of waste. When used in making sawed glue joints it is claimed that the new type ripsaws will effect a further saving of 5 per cent which otherwise would be wasted in milling the joint. Whenever a ripsaw is used for jointing it must be in good mechanical condition, skillfully handled, and well cared for. Under these conditions, and with the use of a good saw, the jointing operation is usually unnecessary. However, it should be remem Α B B illus FIGURE 10.-Ripsaw teeth. The teeth shown in bered that ripping is more wasteful than jointing when it is done only for the purpose of straightedging a piece of stock. Some operators believe that the defective glue joints resulting from gluing up stock directly from the ripsaw may more than compensate for the saving of material. Because of the high production schedule necessary in many mills, because of lack of proper equipment, or because saws and equipment are not given proper care and attention the use of the ripsaw for jointing may in some cases be inadvisable. Planers.-Modern cabinet planers are operated at speeds up to 5.000 or 6,000 revolutions per minute by direct-mounted motors. These machines turn out fine work at the rate of 75 to 100 feet per minute. The old type cabinet planer operates at about half this speed. A multiple guide dimension mill.-The first prize in the 1926-27 waste-prevention contest, conducted by the National Lumber Manufacturers' Association, was awarded to W. M. McHale, of the Menominee Bay Shore Lumber Co., Soperton, Wis. Mr. McHale submitted the design of a multiple guide dimension mill which has been successfully used at his plant. The mill is designed as a complete unit for the production of small dimension stock 1 by 1 by 12 inches and larger from such material as slabs, edgings, and trimmings. It has four stationary set-ups, each equipped with a set of live infeed and outfeed rolls, guides, and a single saw or a series of saws. A maximum of 8 saws may be used in each series with a minimum spacing of 1 inch. The FIGURE 11.-A cut-off saw installation. Note that the saws are aligned in a battery and are well lighted from above with both natural and artificial light. Lumber lifts are located between each pair of saws. (Courtesy Yates-American Machine Co.) fourth section consists of a single saw and a movable guide. This saw may be used in ripping stock wider than 12 inches, which can not be fed through the stationary set-ups, and will handle stock as wide as 27 inches. This section may also be used in manufacturing crating stock. Placed in a temporary location, where it was impossible to install an automatic trimmer and sorter to handle the output, this mill has reduced the cost of producing small dimension stock from mill waste by about 66 per cent. Lumber lifts.-The modern trend is toward the use of lumber lifts in handling stock from the kiln stack to the cut-off saw. The stacks are spotted beside a cut-off saw or between two saws. The stack is then lowered until the top course of stock is on a level with the top of the saw table. When the top course is removed, the lift is elevated until the next lower course is in the same position. Thus, the topmost layer of stock is always at the exact level to permit the sawyer to slide the material on to his table with the least amount of exertion and without the assistance of a helper. In addition to the obvious advantages of decreased handling costs, there is a decrease in the amount of stock damaged in tearing down the kiln load. A Michigan firm found that the installation of a lumber lift eliminated two laborers, one teamster, and three wagons with a gross annual saving of $3,348.05. The purchase and installation cost of a lumber lift amounted to $2,800 and cost $441.25 per year to operate. The net saving of $2,906.80, after deducting operating costs, paid a return of 104 per cent yearly on the investment in lifting equipment. Lumber-marking device.-A lumber-marking device, patented by W. B. Clubine, of Ashland, Wis., may be of interest to producers of small dimension stock. This device is shown in Figure 13 and con FIGURE 12.-Diagram of McHale small dimension mill showing detail of set-ups. Three of these set-ups are stationary, one with 8 saws spaced to cut 1-inch squares, one with 7 saws to cut 14-inch squares, and the third with 6 saws to cut 11⁄2-inch squares. The saw spacing of the set-ups may be changed as indicated in the description. (Courtesy National Lumber Manufacturers Association) sists of a metal frame holding two movable crossarms placed at right angles to each other. The horizontal arm permits the insertion of four rows of cardboard disks at intervals of 12 inch. The vertical arm permits the insertion of disks at intervals of 14 inch. In operation this device is used as follows: Cardboard disks of various colors and with different legends may be used to indicate the various orders. These disks are inserted in the spaces provided on the horizontal and vertical arms at points corresponding to the exact length and width of the rough sizes to be cut. The device is suspended over the cut-off saw infeed table, and an operator marks the location of the various cuttings before the board or flitch goes to the cut-off saw. It is said that one operator can mark stock for one line of production. This method makes cross-cutting and ripping a mechanical operation and should result in closer utilization of raw material. Ο The necessary FIGURE 13.-Lumber marking device for indicating on a board or flitch the location of rough cuttings before the material goes to the cut-off saw. tesy W. B. Clubine) and give other information. (Cour MANUFACTURING ORDERS Desirable orders. It is impossible to arrive at a simple, practical set of rules which will enable the small dimension operator to decide as to whether or not an order is desirable. Various conditions of equipment, transportation, material, etc., have an important influence on these decisions. Generally speaking, a desirable order includes a sliding scale of lengths, widths, and thicknesses from the largest to the smallest. In cutting this type of order it is possible to rework defective pieces to a smaller size, and it is also possible to rework the offal from the largest sizes into other items of the order. Orders for extremely large or extremely small sizes should be avoided. High-grade stock in large sizes is difficult to cut and very wasteful unless manufactured from a good grade of material. However, handling and labor costs on large sizes are considerably reduced. A reasonable amount of small sizes permits closer utilization but also tends to increase labor and handling costs. In discussing the requirements of a desirable order the average width of the stock or lumber from which the dimension is being cut should receive some consideration. Provided that the average width of the grade used is about 512 inches, the following order can |