Handwork in Wood. William Noyes

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СКАЧАТЬ wanted, as at the edger, Fig. 43, or the slasher. From the live rollers the boards are transferred automatically, Fig. 44, by chains running at right angles to the rollers and brought within reach of the edger man. About one-third of the boards of a log have rough edges, and are called "waney." These must go thru the edger to make their edges parallel. The edger man works with great speed. He sees at once what can be made out of a board, places it in position and runs it thru. From the edger the boards are carried to the trimmer, which cuts the length. The lumberman's rule is to "cut so that you can cut again." The so-called 16' logs are really 16' 6". The trimmer, Fig. 45, now trims these boards to 16' 1", so that if desired they can still be cut again. The trimmer may be set to cut at any desired length according to the specifications.

      Fig. 42. Log-Carriage, holding quartered log in position to saw.

      Fig. 43. Double Gang Edger. This machine trims off the rough edges of the "waney" boards by means of the four saws in the main frame of the machine.

      Fig. 44. Automatic Steam Transfer for Timber, Lumber and Slabs. The boards are carried along by the cylinders, CCC, until they hit the bumper, B. This movement admits steam to the cylinder, CY, which raises the revolving chains or skids, which transfers the stock sidewise to other live rollers as required.

      Fig. 45. Automatic Gang Lumber-Trimmer. It may be set to cut automatically to any desired length.

      Fig. 46. Lumber Sorting Shed. Virginia, Minnesota.

      Fig. 47. Wood is carefully and regularly piled in the seasoning-yard.

      The boards are now graded as to quality into No. 1, No. 2, etc., Fig. 46, and run out of the mill, to be stacked up in piles, Fig. 47. Big timbers go directly from the saw on the rolls to the back end of the mill, where the first end is trimmed by a butting-saw or cut-off-saw which swings, Fig. 48. The timber is then shoved along on dead rolls and the last end trimmed by the butting-saw to a definite length as specified, and shoved out.

      One of the most remarkable features of the modern mill is its speed. From the time the log appears till the last piece of it goes racing out of the mill, hardly more than a minute may have elapsed.

      Fig. 48. Cut-off-Saw. This saw trims the ends of timbers.

      A large part of the problem of sawmilling is the disposal of the waste. The first of these is the sawdust. In all first class mills, this together with shavings (if a planing-mill is combined) is burned for fuel. It is sucked up from the machines and carried in large tubes to the boiler-room and there is mechanically supplied to the fires. The slabs, once considered as waste, contain much material that is now utilized. From the live rolls, on which all the material falls from the main band-saw, the slabs are carried off by transfer chains, and by another set of five rollers to the "slasher," Fig. 50, which consists of a line of circular-saws placed 4' 1" apart. This slasher cuts up the slabs into lengths suitable for lath or fence-pickets, Fig. 49. Or they can be resawn into 16" lengths for shingles or fire-wood.

      Fig. 49. Ten Saw Gang Lath Bolter. This machine cuts up material lengthwise into laths.

      Fig. 50. Slab-Slasher. This machine cuts up the slabs into lengths suitable for lath or fence-pickets.

      From the "slasher" the 4' 1" lengths are carried on by traveling platforms, chains, etc., to the lath-machines, Fig. 51, where they are sawn up, counted as sawn, bound in bundles of 100, trimmed to exactly 4' in length and sent off to be stored. The shingle bolts are picked off the moving platforms by men or boys, and sent to the shingle-machine, Fig. 52, where they are sawn into shingles and dropped down-stairs to be packed. Shingle-bolts are also made from crooked or otherwise imperfect logs.

      Of what is left, a good part goes into the grinder or "hog," Fig. 53, which chews up all sorts of refuse into small chips suitable for fuel to supplement the sawdust if necessary. Band-saws make so little dust and such fine dust that this is often necessary.

      Fig. 51. Combination Lath-Binder and Trimmer. With this machine the operator can trim the bundles of lath simply by tilting the packing frame over from him causing the bundles to pass between the saws, thereby trimming both ends at one movement.

      Fig. 52. Hand Shingle-Machine. This machine is used in Sawmills in which it is desired to utilize slabs and trimmings by sawing shingles therefrom, or to saw shingles from prepared bolts.

      If there is any refuse that cannot be used at all it goes to the scrap-pile, Fig. 54, or to the "consumer," the tall stack shown in Fig. 37, see p. 33.

      Boards ordinarily sawn from logs are "slash-sawn," i. e., they are tangential or bastard, each cut parallel to the previous one. By this process, only the central boards would be radial or "rift" boards.

      Fig. 53. Edging grinder or Hog. It cuts any kind of wood into coarse or fine chips suitable to be handled by chain conveyor or blower.

      But, for a number of reasons, radial boards are better. They warp less because the annual rings cross the board more evenly. Yellow pine flooring that is rift-sawn is more valuable than slash-sawn, because the edge of the annual rings makes a more even grain, Fig. 55. Where slash-grained flooring is used, the boards should be laid so that the outside of each board will be up in order that the inner rings may not "shell out."

      In sawing oak for valuable furniture or trim, the log is first "quartered" and then the quarters sawn up as nearly radially as is desired. There are various methods of cutting quartered logs, as illustrated in Fig. 56.

      In making staves for water-tight barrels, it is essential that they be cut radially in the log, in order that the staves be as non-permeable to water as possible.

      Fig. 54. Scrap-Pile. Oscilla. Georgia.

      Fig. 55. Slash-Grain and Comb-Grain Flooring.

      Fig. 56. Methods of Sawing Quartered Logs.

SAWMILLING

      References4

      Trout, Cassier 11: 83, 184.

      Woodcraft 5: 56, СКАЧАТЬ