The geared engine has also been used as a subst.i.tute for cable power, in "yarding" operations. The "turns" of logs are drawn over the ground between the rails, being fastened to the rear of the engine by hook and cable. This has proved to be a very economical use of power and plant.
[Ill.u.s.tration: Fig. 29. Donkey Engine Yarding.]
[Ill.u.s.tration: Fig. 30. Giant Raft. In the background is a completed raft; in the foreground a cradle in which a raft is being built.]
Another method of traction where the woodland is open enough is with a traction engine. The ones employed have sixty to one hundred horse power. The great logs may be placed on wood rollers, as a house is when moved, or the logs may be hauled in on a low truck with broad wheels. The "tractor" hauls the log direct to the railway if the distance is not too great.
[Ill.u.s.tration: Fig. 31. Snow Locomotive. Takes the place of 12 teamsters and 12 horses. Minnesota.]
In Northern Michigan a "snow locomotive," Fig. 31, is coming into use, which has tremendous tractive power, hauling one hundred to one hundred fifty tons of lumber over snow or ice. It moves on runners, but there is between them a large cylinder armed with teeth. This cylinder can be raised or lowered by the operator as it moves over the surface of the ground. The teeth catch in the snow or ice, and since the cylinder is heated by the exhaust steam, it melts and packs the snow for the trucks following it. The drum is six feet in diameter, with walls an inch and a half thick, and it weighs seven tons. It is used in all sorts of places where horses cannot go, as in swamps, and by subst.i.tuting wheels for runners it has even been used on sand.
In the Canadian lakes there has been devised a queer creature called an "alligator," a small and heavily equipped vessel for hauling the logs thru the lakes. When its operations in one lake are finished, a wire cable is taken ash.o.r.e and made fast to some tree or other safe anchorage, the capstan on its forward deck is revolved by steam and the "alligator" hauls itself out of the water across lots to the next lake and begins work there.
The greatest improvement in water transportation is the giant raft, Fig. 30. When such a raft is made up, logs of uniform length are placed together, the width of the raft being from sixty to one hundred feet and its length, one thousand feet or more. It may contain a million board feet of timber. The different sections are placed end to end, and long boom sticks, i. e., logs sixty to seventy feet long, are placed around them to bind the different sections together, and finally the whole ma.s.s is heavily chained. Such a raft has been towed across the Pacific.
LOGGING.
REFERENCES[*]:
River Lumbering.
Pinchot, _Primer_, II, pp. 40-53.
White, _Blazed Trail_, pp. 5-15, 25, 38-39, 52-53, 63-65, 72-85, 91-99, 113-125, 134, 181-196, 216-229, 257, 268, 320-343, 355, 365 ff.
_For. Bull._, No. 34, pp. 33-41, Fox.
White, _Jun. Mun._, 10: 362.
Hulbert, _Outl._, 76; 801.
_Wood Craft_, 4: 55.
Smith, K., _World"s Work_, 7: 4435.
Mechanical Methods.
_World"s Work_, 7: 4435.
_Outl._, 76: 812.
Bruncken, p. 86.
Bruncken, pp. 76-87.
Munn, _Cosmop._, 37: 441.
Roth, _First Book_, pp. 133-174.
Hovey-King, _Rev. of Rev._, 27: 317.
Jones, _Cosmop._, 15: 63.
Price, _World"s Work_, 5: 3207.
_For. Bull._, No. 61.
_Ca.s.sier_, 29: 443, April, "06.
_Cosmop._, 37: 445.
_Rev. of Rev._, 28: 319.
[Footnote *: For general bibliography see page 4.]
CHAPTER II.
SAWMILLING.
The princ.i.p.al saws in a mill are of three kinds, the circular, Fig.
32, the gang, Fig. 33, and the band, Fig. 34. The circular-saw, tho very rapid, is the most wasteful because of the wide kerf, and of course the larger the saw the thicker it is and the wider the kerf.
The waste in sawdust is about one-fifth of the log. In order to lessen this amount two smaller saws, one hung directly above the other, have been used. One saws the lower half of the log and the other the upper half. In this way, it is possible to cut very large logs with the circular-saw and with less waste. The circular-saw is not a perfectly flat disc, but when at rest is slightly convex on one side and concave on the other. This fullness can be pushed back and forth as can the bottom of an oil-can. When moving at a high rate of speed, however, the saw flattens itself by centrifugal force. This enables it to cut straight with great accuracy.
[Ill.u.s.tration: Fig. 32. Double Circular-Saw and Carriage.]
A gang-saw is simply a series of straight saw-blades set in a vertical frame. This has a reciprocating motion, enabling it to cut a log into a number of boards at one time. It has this drawback, that it must cut the size of lumber for which it is set; that is, the sawyer has no choice in cutting the thickness, but it is very economical, wasting only one-eighth of the log in sawdust. A special form is the flooring gang. It consists of a number of saws placed one inch apart. Thick planks are run thru it to saw up flooring.
[Ill.u.s.tration: Fig. 33. Gang-Saw.]
[Ill.u.s.tration: Fig. 34. Band-Saw.]
The band-saw is fast displacing the other two, wherever it can be used. It cuts with great rapidity and the kerf is narrow. When first used it could not be depended upon to cut straight, but by utilizing the same principle that is used in the circular-saw, of putting the cutting edge under great tension by making it slightly shorter than the middle of the saw, it now cuts with great accuracy. Band-saws are now made up to 12 inches wide, 50 feet long, and run at the rate of 10,000 feet a minute. They are even made with the cutting teeth on both edges, so that the log can be sawed both going and coming. This idea was unsuccessful until the invention of the telescopic band-mill, Fig. 35. In this the entire mechanism carrying the wheels on which the band-saw revolves can be moved up and down, so as to bring the point where the saw leaves the upper wheel as close to the top of the different sized logs as possible.
[Ill.u.s.tration: Fig. 35. Double-Carrying Telescopic Band-Mill. Mill in raised position for large log.]
[Ill.u.s.tration: Fig. 36. Jack-Ladder, with Endless Chain.]
The usual modern mill is a two story building, Fig. 37, built at a convenient locality both for receiving the logs and for shipping the lumber. Whether the logs arrive by water or by rail, they are, if possible, stored in a mill-pond until used in order to prevent checking, discoloration, decay, and worm attack. From the pond they are hauled up out of the water on to a "jack-ladder," by means of an endless chain, provided with saddles or spurs which engage the logs and draw them up into the second story on to the log slip, Fig. 36.
[Ill.u.s.tration: Fig. 37. Two-Story Mill at Virginia, Minnesota, Showing Jack-Ladders and Consumer.]
[Ill.u.s.tration: Fig. 38. Log-Flipper.]
[Ill.u.s.tration: Fig. 39. Log-Stop and Loader. By letting steam into the cylinder, the projecting arm revolves, rolling one log over onto the carriage and holding the next one till wanted.]
After the logs have entered the mill, they are inspected for stones lodged in the bark, and for spikes left by the river men, and then measured. Under the log-slip is the steam "flipper" or "kicker," Fig.
38, by means of which the scaler or his a.s.sistant, throwing a lever, causes the log to be kicked over to one side or the other, on to the log-deck, an inclined floor sloping toward the saw-carriage. Down this the log rolls until stopped by a log-stop, or log-loader, Fig. 39, a double-aimed projection, which prevents it from rolling on the carriage till wanted. This stop is also worked by steam. By letting the steam into the cylinder which controls it, one log is rolled over on the carriage and the next one held. The log on the carriage is at once "dogged," that is, clamped tight by iron dogs, the carriage is set for the proper cut, and moves forward to the saw which cuts off the first slab. The carriage is then "gigged" or reversed. This operation offsets the carriage one-eighth of an inch so that the log returns entirely clear of the saw. In the same way two or three 1"
boards are taken off, the dogs are then knocked out, and the log canted over half a revolution. This is done by means of the "steam n.i.g.g.e.r," Fig. 40, a long, perpendicular toothed bar which comes up thru the floor, engages the log, and turns it over till the sawn side comes up against the knees of the carriage. The log is dogged again and a second slab and several boards are taken off. The log or "stock"
as it is now called, is 10", 12", 14", or 16" thick; the "n.i.g.g.e.r" then gives it a quarter-turn, leaving it lying on a sawn side. It is dogged again, and all sawn up except enough to make a few boards. This last piece is given a half-turn, bringing the sawn side against the knees, and it is sawn up. Each board as it is sawn off is thrown by the board-flipper or cant-flipper,[2] Fig. 41, on to the "live rollers,"
which take it to the next process. Another log comes on the carriage and the process is repeated.
[Footnote 2: A "cant" is a squared or partly squared log.]
[Ill.u.s.tration: Fig. 40. The Steam n.i.g.g.e.r. The toothed bar turns the log over into the desired position.]
[Ill.u.s.tration: Fig. 41. Steam Cant-Flipper. This machine is used to move cants, timber, or lumber from live rollers to gangs, band resaw mills, or elsewhere. The timber is discharged upon skid rollers, as shown, or upon transfer chains.]
[Ill.u.s.tration: Fig. 42. Log-Carriage, holding quartered log in position to saw.]
The saw-carriage, Fig. 42, is propelled forward and back by a piston running in a long cylinder, into either end of which steam can be turned by the operator.
[Ill.u.s.tration: 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.]
[Ill.u.s.tration: Fig. 44. Automatic Steam Transfer for Timber, Lumber and Slabs. The boards are carried along by the cylinders, CCC, until they hit the b.u.mper, 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.]