Handtools for Trail Work

Tools for Sharpening, Continued

Files

Files come in single, double, curved, or rasp cuts. Single-cut files have one series of parallel teeth angled 60° to 80° from the edge, and are used for finishing work. Double cuts have two series of parallel teeth set 45° to each other; they are used for restoring shape. Curved and rasp cuts are used for shaping soft metals and wood, respectively.

This file has a knuckle guard made
from old linen hose.

Files vary in length and shape. Files are measured from the point to the heel, excluding the tang (the tip used to attach a handle). Length determines the coarseness of files. There are generally three degrees of file coarseness: bastard, second cut, and smooth. The bastard will be the coarsest file available, however only when it is included among different cuts of files of the same length. Of the many shapes of files currently on the market, you will probably not often use mill and flat files. Mill files are single-cut, and flat files are double-cut. A 10-inch mill bastard file is good for all-around tool sharpening.

Comparative coarseness of
files of uniform length.

Before filing, fit the file with a handle and knuckle guard. Always wear gloves on both hands to prevent cuts from the sharpened edge. Secure the tool so both hands are free for filing. Use the largest file you can, depending on the size, nature, and workable stroke length of the job. Remember that files are designed to cut in one direction only. Apply even pressure on the push stroke, then lift the file up and off the tool while returning for another pass. Store or transport files so they are not thrown together and protect them from other tools.

Maintain files with a brush or file card. A file brush has coarse and fine bristles and a wire pick for extracting trapped filings. A card has a small brush and a wire scorer.

Always wear gloves and goggles while filing.

Grinders

A manually operated sandstone wheel that runs through or receives dripping water is the best all-round grinding tool. The wheel turns slowly enough to allow monitoring of the amount of metal being removed and the water keeps the blade cool. For volume sharpening, a sandstone wheel may be provided with mechanical power, but only if it remains geared to the same maximum rpm that a hand operation would allow.

Electric bench grinders quickly reshape damaged tools, but extreme caution must accompany their use. Improper electric grinding can ruin both the bevel and temper of a tool. High speeds remove metal from the blade quickly, which can cause it to weaken and chip easily. High speeds also allow heat buildup in tool heads, which can destroy temper and make it impossible for the blade to hold an edge. Using electric grinders, grind slowly and keep the blade cool. Inspect blades frequently to prevent too much metal from being ground from the blade. Dip the tool in water or cool it in open air. Avoid grinding on flat sides of electric wheels because they will weaken and break.

Grinding parallel to bevels maintains the correct angle.

Sharpening a blade on
a grinding wheel.

Finish the edge with a whetstone as if you were touching up. Blade and edge bevels may vary with individual preference and based on the task at hand. When sharpening an ax, for example, the blade bevel for use in softwoods might be thinner than one for hardwoods. Experience, observation, and experimentation will determine the appropriate bevels for each tool and cutting job.

Use adequate safety equipment when grinding tools. Always wear heavy leather gloves. Long-sleeved shirts and leather aprons will help prevent small burns from sparks or metal shavings. Proper eye protection is essential, including eye shields or safety goggles for operators and shields and hood guards on grinders. Hold portable grinders securely when using.