TOOLS FOR GRADING.
Picks are made of various styles, according to the class of material in which they are to be used. Fig. 28 shows the form usually employed in street work. Fig. 29 shows the form generally used for clay or gravel excavation.
The eye of the pick is generally formed of wrought iron, pointed with steel. The weight of picks ranges from 4 to 9 lb.
Shovels are made in two forms, square and round pointed, usually of pressed steel.
Ploughs are extensively employed in grading, special forms being manufactured for the purpose. They are known as "grading ploughs," " road ploughs," " township ploughs," etc. They vary in form according to the kind of work they are intended for, viz.: loosening earth, gravel, hardpan, and some of the softer rocks.
These ploughs are made of great strength, selected white oak, rock elm, wrought steel and iron being generally used in their con struction. The cost of operating ploughs ranges from 2 to 5 cents per cubic yard, depending upon the compactness of the soil. The quantity of material loosened will vary from 2 to 5 cubic yards per hour.
Fig. 31 shows the form usually adopted for loosening earth. This plough does not turn the soil, but cuts a furrow about 10 inches wide and of a depth adjustable up to 11 inches.
In light soil the ploughs are operated by two or four horses; in heavy soils as many as eight are employed. Grading ploughs vary in weight from 100 to 325 lb.
Fig. 32 illustrates a plough specially designed for tearing up macadam, gravel, or similar material. The point is a straight bar of cast steel drawn down to a point, and can be easily repaired.
Scrapers are generally used to move the material loosened by ploughing; they are made of either iron or steel, and in a variety of form, and are known by various names, as " drag," " buck," " pole," and " wheeled". The drag scrapers are usually employed on short hauls, the wheeled on long hauls. Fig. 33 illustrates the usual form of drag scrapers.
Drag scrapers are made in three sizes. The smallest, for one
horse, has a capacity of 3 cubic feet; the others, for two horses, have a capacity of 5 to 71 cubic feet. The smallest weighs about 90 lb., and the larger ones from 94 to 102 lb.
Buck scrapers are made in two sizes—two-horses, carrying 7 cubic feet; four-horses, 12 cubic feet.
Pole scraper, Fig. 34, is designed for use in making and leveling earth roads and for cutting and cleaning ditches; it is also well adapted for moving earth short distances at a minimum cost. Wheeled scrapers consist of a metal box, usually steel, mounted on wheels, and furnished with levers for raising, lowering, and dumping. They are operated in the same manner as drag scrapers, except that all the movements are made by means of the levers, and without stopping the team. By their use the excessive resistance to traction of the drag scraper is avoided. Various sizes are made, ranging in capacity from 10 to 17 cubic feet. In weight they range from 350 to 700 lb.
Wheelbarrows. The wheelbarrow shown in Fig. 36 is con structed of wood and is the most commonly employed for earth work. Its capacity ranges from 2 to 21 cubic feet. Weight about 50 lb.
The barrow, Fig. 37, has a pressed-steel tray, oak frame, and steel wheel, and will be found more durable in the maintenance department than the all wood barrow. Capacity from 31 to 5 cubic feet, depending on size of tray.
The barrow, Fig. 33, is constructed with tubular iron frames and steel tray, and is adaptable to the heaviest work, such as moving heavy broken' stone, etc., or it may be employed with ad vantage in the cleaning department. Capacity from 3 to 4 cubic feet. Weight from 70 to 82 lb.
The maximun distance to which earth can be moved economic ally in barrows is about 200 feet. The wheeling should be per formed upon planks, whose steepest inclination should not exceed 1 in 12. The force required to move a barrow on a plank is about part of the weight; on hard dry earth, about part of the weight.