Before grinding this tool, notice the shape it should have. The end is ground in an elliptical form, the bevel being practically a straight line, as shown at AB, Fig. 14.
To grind the gouge, apply it to the grindstone, following the general rule given; then slowly rotate it from side to side until the end is the desired shape (see Fig. 14).
The gouge is sharpened on the slip stone. Hold the gouge in the left hand and the slip stone in the right, as shown in the illustration, Fig. 15. Oil is used on the slip stone. After the edge on the outside of the gouge has been rubbed enough, apply the round edge of the slip to the inner or concave side, taking care that the slip is in contact with the gouge the whole length of the slip. Remove the wire edge by rubbing with the slip stone and leather strop.
The skew chisel. The skew chisel is a tool commonly used to finish straight-lined work, such as the sides and ends of cylinders and cones, and in making beads and long convex curves. By referring to Fig. 16 it will be seen that the end is not a right angle, as is the case with the carpenter's chisel, but is beveled or "skewed." This beveled or skewed end is made so that the operator will have better control of the cutting edge. If it were at right angles, he would have to swing the handle so far to the side that it would be rather difficult to obtain a perfectly straight cut. As will be seen from Fig. 16, the chisel is ground on both sides, bringing the cutting edge into the center of the blade. If the tool is ground unevenly, as indicated by Fig. 17, it will be much more difficult to control. The tool is guided more by the side of the blade than by its edge; therefore, if the cutting edge is parallel with its sides, as in Fig. 16, the angle at which the tool is held for any cut is easily judged by the side of the blade, whereas if the edge is unevenly ground, the angle at which it must be held can only be determined by experimentation.
Fig. 18 shows the position of the chisel on the grindstone. Apply the tool to the stone by the general rule given for grinding (page 13), and move it from side to side of the stone, as indicated by the arrow points. The angle, or skew, at which to grind the end should be about 750 (see Fig. 16). The skew is sharpened on the oilstone. The bevel should be held flat on the stone, first on one side and then on the other, until the wire edge is removed. By continued sharpening the chisel becomes rounded, as shown by Fig. 19, and must be ground again. Time is saved by grinding and sharpening promptly. Tools will cut faster and smoother when the cutting edges are "keen and sharp" than when "blunt and dull."
The round-nose scraping tool. This tool, shown in Fig. 20, is used (as its name implies) to cut by scraping rather than by paring. It is used on fillets and concave surfaces. The method of scraping is given on page 26. Sharpen the tool on the large oilstone, revolving it in the same manner as a gouge; turn, and keep the flat side of the tool in contact with the stone. Grind it as you would the gouge.
The square-nose scraping tool. This tool (see Fig. 21) is, used in the same manner as the round-nose scraping tool, and is applied on straight and convex surfaces. Sharpen it on the large oilstone, just as you would sharpen an ordinary bench chisel.
The diamond-point tool. This tool, sometimes named a "spear-point" or a "right-and-left" tool, is used on inside work or on work where the ordinary skew chisel could not be used to advantage. Fig. 22 shows the general shape it should have, but the angle can be changed to suit special work. Grind the bevels as shown in figure; sharpen on a slip stone.
The cut-off or parting tool. Fig. 23 shows this tool; as its name implies, it is used to cut off work where another tool could not be used to advantage. It is also used for "sizing" work (see Fig. 44 B as an example of its application in sizing). Grind to the shape shown in Fig. 23 and sharpen on the oilstone.
The sizing tool. The sizing tool (Fig. 24) is used on work where a number of pieces are to be of the same diameter, as, for instance, the dowels on the ends of spindles, and the ends of chisel handles where ferrules are to be used. Grind and sharpen, the same as the cut-off tool.
Tools used for measuring. The calipers. The outside calipers (Fig. 25) are used to measure the outside diameters; the inside calipers (Fig. 26) are used for inside diameters of rings, holes, etc.
The rule. A two-foot folding rule, graduated to sixteenths, makes a serviceable tool for measuring.
The dividers. The dividers (Fig. 27) are used in many ways. Their application in measuring will be given with the problems with which they are to be used.
Tools used for sharpening. The slip stone. The slip stone (Fig. 28) is used to sharpen gouges and tools that are curved in their section.
The oilstone. Oilstones are either natural or artificial. The so-called India oilstone is preferable for ordinary sharpening. Use oil on any stone when sharpening a tool.
The strop. The strop is a piece of leather cut into such shape as to conform on its edge to the curve of a gouge. The side of the strop is used for tools that are flat or straight on the edge.
Sizes of chisels and gouges. The size of a gouge or chisel is determined by its width. Turning chisels and gouges come in sizes ranging by eighths, from one eighth of an inch up to two and one-half inches.
Lathe-tool practice.1 The art of wood turning cannot be learned from a book, but book instruction, supplemented by practice under the guidance of an instructor, will quickly enable the careful student to do good work. The exercises that follow are intended to teach the art of wood turning through various operations on the speed lathe.