- Measuring Tapes
- Framing Squares
- Plumb Bob
- Surveyors Transits and Electronic Instruments
- Draw Knives
- Bark Spuds
The standard tools used for trail construction are also needed for building a trail in a wetland. Standard trail tools are not described here. Instead, this report focuses on tools specifically needed for wetland trail construction. Find out more about handtools in MTDC's Handtools for Trail Work report (0523-2810-MTDC) and video (98-04-MTDC).
Measuring tapes are a necessity for estimating and constructing a wetland trail. Construction measurements for wetland trails are often taken from the trail centerline. It is frequently necessary to divide by two. Metric measurements offer an advantage over English measurements in such cases. In addition, there is a move from the English system of measurement to the metric system (Appendix F). Buy new tapes that are graduated in both systems.
Tapes 50 feet and longer are made of fiberglass, cloth, or steel. Fiberglass is best for the wet, brushy environment of wetlands. Cloth is not recommended because it will wear and rip easily. Long steel tapes may rust, kink, and break when used in wetlands. Short steel tapes, 6 to 30 feet long, are essential.
The longer tapes are best for estimating quantities of materials and hours needed for construction and for laying out centerlines of sleepers, bents, and other structures. The shorter steel tapes are handy for the actual construction.
Framing squares (figure 73) are thin, L-shaped pieces of steel with a 90-degree angle at the corner. Each leg of the L is 1 to 2 inches wide and graduated in inches (or centimeters) from both the inside and outside corners of the L. The legs may be 8 inches to 2 feet long. Framing squares are used to mark hole centers and timbers to be cut at a 90- degree angle and to provide a straight, firm edge for marking angled cuts.
A plumb bob is a solid steel or brass cone, 3 inches long by 1½ inches in diameter. The plumb bob accurately transfers measured points above the ground to comparable points on the ground. It is useful for locating the centers of holes to be dug.
Specialized levels are useful for wetland trail work. An Abney hand level or a clinometer is accurate enough to be used for setting grades during the preliminary layout of most wetland trails (figure 74). String or line levels and carpenters and masons levels are needed during construction.
There are two types of string or line levels: one establishes percent of grade easily, the other does not. Each level is about 3 inches long by ½ inch in diameter and has a hook at each end to hang the level on a string. The string is pulled tight between two points in an almost horizontal line. One of the points must be at a known elevation. The string level will be used to establish the elevation of the other point.
The most common type of string level has two marks on the level tube. These marks are equidistant from the high point of the level tube. Center the level bubble between the two marks on the tube by raising or lowering the string at the second point. When the bubble is centered, the string is level. If the tread is to be level, this is the elevation to be met. If the tread is to be sloped, the difference between the two points must be calculated; the elevation to be met is established by measuring the difference needed, up or down, from the level line.
In the second type of string level, the high point of the level bubble is off center. The level tube has five graduations. The first two are widely spaced. The rest are closer together, but evenly spaced. When the bubble is centered between the two widely spaced marks, the string is level. When the edge of the bubble touches the third mark, the string is at a 1-percent grade, the fourth mark is at a 2-percent grade, and so forth. A string level is accurate enough to begin to establish relative elevations and slopes for small wetland trail projects (figure 75).
Almost any type of string can be used for a stringline, but for repeated use a professional stringline is best. This type of stringline is a tightly braided string wound around a short, narrow piece of wood, plastic, or metal. Usually there is a metal clip, or a loop, tied on the end.
The stringline extends a straight line to reference the location of the next section of construction. The stringline can also be used with string levels to establish relative elevations and slopes.
A chalkline is another type of stringline used to mark a straight line between two points on a flat surface. The marked line is commonly a guide for sawing.
Professional chalklines come in a metal case that holds the coil of string and the chalk dust. One end of the chalkline is held tightly at a fixed point on the surface of the object to be marked. The chalkline is stretched to the mark at the opposite end and held tightly at that point. Hold the chalkline at about midpoint, pull the chalkline straight up from the surface and release it. The chalkline will snap back into place, leaving a sharp, straight line of chalk between the two points.
A chalkline is useful for marking the centers of sleepers and bents for a deck that needs to be in a straight line, or the edges of a deck to be trimmed uniformly, or the edges of a log to be cut with a flat face.
There used to be a distinction between carpenters levels and masons levels. Carpenters levels were wood or wood with steel strips to protect the edges. The masons level was all or mostly steel. Today, wood, steel, aluminum and plastic are used in either type of level.
These levels are available in lengths of from 2 to 6 feet. Given the abuse trail tools take, steel or aluminum levels are best. A 3- to 4-foot-long level is more accurate than shorter levels. These levels are easier to pack than 5- to 6-foot-long levels. Plastic levels are also available and cost less.
The levels have three tubes mounted in the body of the level. One level tube is parallel with the length of the level, one is perpendicular to it, and one is at 45 degrees to the other two. When a level bubble is centered, the edge of the level is either level, vertical, or at 45 degrees.
A torpedo level is steel or aluminum and plastic and only 8 to 12 inches long and 1 to 2 inches wide. It is used to determine if a surface within a confined area is level, for example the surface of a notch. Although the torpedo level is not as accurate as the longer levels, it can be used to check whether an item is out of level, or out of plumb. If so, a more accurate level can be used to make the corrections.
Post levels save time when setting posts and piles. They are basically plastic right angles that are 4 inches long in three dimensions. Two level tubes are mounted in the two faces of the level. Set the level along the side of the post or pile, and use a crowbar or shovel to adjust the post or pile until it is plumb (figure 76).
Hand-held tapes and levels are adequate for short destination or loop trails in a wetland, or for low, poorly drained sections of existing trails. However, for trails longer than a quarter mile or over undulating terrain, more precise measurements might avoid future problems. Control points for elevation and slope can be established using surveyors transits or a variety of electronic instruments.
Old surveyors levels or transits may be hiding in a closet or storage area at some agency offices. Blow the dust off and try to find someone who knows how to run the instrument. A builders level or transit may be less accurate, but should work. A surveyors level rod will be needed to obtain distances and elevations. Distances can be quickly measured optically using stadia.
Two types of electronic distance-measuring instruments (EDMs) are available. The least expensive type is hand held and can measure distances across a flat surface to a point from 2 to 250 feet away. This type of instrument does not provide elevations of points or information needed to determine slopes and relative elevations. It will not provide accurate distance measurements if vegetation impedes the line of sight.
More expensive instruments can measure distances up to 12,000 feet with an accuracy of 0.02 to 0.03 feet. This type of instrument can only be used where there is a direct, clear line of sight.
Global positioning systems (GPS) provide horizontal positioning through the use of coordinates and can provide elevations. This equipment may cost from a hundred dollars to several thousand dollars depending on the quality. The skills needed to operate GPS equipment vary depending on the equipment's sophistication and accuracy.
The accuracy of small hand-held instruments can be close to 1 meter (3.28 feet), in open, relatively level terrain, sufficient accuracy for trail work if frequent points are taken along the route.
High-resolution GPS instruments are also available for more precise work. These instruments require extensive training and experience in their use. They are also very expensive. This technology changes quickly. Technological advances and reduced costs, coupled with the recent relaxation of military security coding, suggest a much wider use of GPS in the future.
Most timbers and logs used in wetland trail construction are of relatively small diameter. Usually the largest are the piles, 6 to 10 inches in diameter.
If only a few pieces must be cut, or if wilderness regulations require, a one- person crosscut saw can do the job. This is an old-fashioned large handsaw. The blade is 3 to 4 feet long and heavier than a carpenter's handsaw, with much larger teeth (figure 77).
If many pieces of wood need to be cut, and if regulations permit them, chain saws do faster work for cutting the small sleepers, piles, and planks used for some wetland trails. A small, light-weight saw designed for tree pruning is better for cutting horizontally on vertical piles, posts, and other items. Pruning saws are available weighing 8 pounds, with a 12- to 14-inch bar.
The sawyer should be adequately trained and experienced in the use of the chain saw and the safety equipment. Most government agencies, the Forest Service included, require workers to receive special training and certification before they are allowed to use a chain saw.
Small hand-held pruning saws are used on most projects. Most types have a curved blade 12 to 26 inches long. For wetland work, the shorter saws are adequate. Some saws have a wood or plastic handle that the blade folds into when it is not being used. Small pruning saws with a straight blade 6 to 8 inches long are available. The short saws with the straight blade work well for cutting shallow notches in log sleepers. When the saws are folded, they can be carried in a pocket (figure 78).
Three kinds of axes are commonly used in trail work: single-bit, double- bit, and broad axes. The hatchet is not included in this tool list. A Maine guide once wrote that the hatchet is the most dangerous tool in the woods. He may have been right. It takes only one hand to use a hatchet. The other hand is often used to hold the piece of wood to be cut-not the safest thing to do. Few trail crews include a hatchet in their toolbox.
If the hatchet is the most dangerous handtool in the woods, the carpenters adz is the second most dangerous. A person getting hurt with a hatchet has usually been careless. It is not necessary to be careless to get hurt using an adz. The carpenters adz is used for cutting a level surface on a log for some types of puncheon and gadbury and for removing knots and bulges on log surfaces.
The blade of a carpenters adz is 5 inches wide and similar to an ax except that it is mounted perpendicular to the line of the handle, similar to a hoe. The edge must be sharp. The handle is curved, similar to a fawn's-foot handle on a single-bit ax.
Workers using an adz normally stand on a wide log (16 inches or more in diameter) and swing the adz toward their feet, almost like hoeing a garden. An adz can be used on smaller- diameter logs by a worker standing next to the log and chopping sideways along the length of the log. When one face of the log is cut to a level plane, the log can be turned and another face can be cut. It is extremely difficult to use a long-handled adz to cut anything but the upper surface of a log.
Two other types of carpenters adzes have short handles. They are not suitable for shaping large logs, but work well for removing knots and bulges and for cutting notches. Short- handled adzes are made with a straight or concave blade, about 3 inches wide. Striking the back of the adz head with a hammer will eventually crack the head (figure 79).
Small block planes can be used for shaping bevels and chamfers, for removing unevenness where two pieces of wood butt together, and for smoothing splintery edges that visitors might touch. Block planes are small, about 2 inches wide and 4 inches long, and easily packed to the work site (figure 80).
Draw knives are often used to peel the bark off logs. Logs will last longer without the bark. Draw knives work best on logs with thin bark.
Draw knives have either straight or concave steel blades that are 12 to 15 inches long with a wooden handle at each end. The draw knife is pulled toward the worker. The straight draw knife does not put as much of the edge against the wood as the concave knife, making the concave knife more efficient and more popular (figure 81).
Bark spuds are better suited for removing the bark from thick-barked or deeply furrowed logs and logs with many knots or large knots. Normally, logs are most easily peeled when the tree is still green, but this characteristic varies by tree species. Bark spuds are from 18 inches to 6 feet long. All have a steel head that is 2 to 3 inches wide and 3 to 5 inches long, sharpened on the end and both sides. The wooden handle is 15 inches to 5½ feet long (figure 82).