The long handled gouge used for hollowing, varies from three eighths to about threequarters of an inch in width, according to the size of the aperture to be made. The end of the work is first turned true and moderately flat, the gouge is then traversed from the circumference to the center, cutting upon the surface in the usual manner, lying on its side, the bevil in coincidence. Instead of being withdrawn when it arrives at the center, while still cutting, it is thrust further forward in the same line a little beyond it; and at the same time, is urged into the face of the work, by the cutting bevil being made to assume a greater angle than when surfacing. The increased inclination being effected by a slight pull upon the shaft of the tool with the left hand, accompanied by a slight sway of the body to the right.

The cutting edge thus thrown out of coincidence, buries t 2 itself in the face of the work, whereupon, while still cutting it is raised by gradually depressing the handle, until the gouge arrives at the dotted position fig. 364. As the cutting edge travels upwards, the shaft of the gouge is also made to rotate a quarter turn upon itself, by slowly turning the right wrist; the two motions are simultaneous and terminate as the tool arrives at the end of its ascent, when its convex side is uppermost, and its cutting edge at a tangent to the internal circle. The path of the gouge in hollowing therefore, carries the bevil of the tool from the position of coincidence with the surface, to that of a rather oblique tangent to the internal circle, and is the effect of a quadruple motion; the tool is advanced considerably beyond the center, is raised in the curve of the dotted line, is turned one quarter round, and travels laterally upon the rest, fig. 366, a distance equal to the depth hollowed in the work. The cut commenced on the surface, is carried on without cessation into the hollowing, when the whole of the cutting takes place with the edge of the tool pushed beyond the center and reversed; the lathe having continuously revolved towards the operator.

Fig. 364. Fig. 365. Fig. 366.

Hollowing With The Gouge Hook And Side Tools 400286

It is however by no means necessary that the tool should proceed along its entire path, to make the cut at one sweep, but it may be arrested and the cut recommenced, as often as may be found convenient. The gouge cuts with avidity and requires to be held with considerable firmness, and this is the more necessary as the aperture becomes deeper by every succeeding cut. The first, sinks a hollow or dishes the surface, leaving an opening rather high at the center, with a round corner at the circumference. The succession of cuts, fig. 365, leaving the work an irregular internal cylinder, the sides and base of which are subsequently turned square. The reversed position of the tool beyond the center is unique and confined to the gouge, with which it is rapid, very efficient and not difficult to acquire. Hollowing with the gouge however, cannot usually be carried to a greater depth than that of about the radius of the aperture; at increased depths the tool is difficult to direct, and is exchanged for the hook tool, fig. 359 or 362.

In hollowing the internal cylinder with the hook tool, the rest is placed above the center, sometimes parallel with the surface and at others rather obliquely to it. The left hand grasped around the shaft of the hook tool, and the right at the extremity of the handle, are both well above its cutting edge which overhangs the rest, fig. 368 ; when the tool is said to be held "underhand," in distinction to its overhand position, as on the cylinder fig. 335.

In holding the tool under hand, the left hand is grasped around its shaft, knuckles uppermost. The right hand may either grasp the handle as before, the thumb uppermost, the arm at right angles bent by the elbow, or, which is generally more convenient, with the knuckles uppermost, the wrist underneath the handle; the whole arm close to the body almost in the same plane with the tool, and the right hand against the right side of the chest. The end of the handle is sometimes placed on the right shoulder, the hand is then shifted down the handle, so as to be midway between the shoulder and the rest; this position is more required for metal than for wood turning. The height of the rest, fig. 368, places the stem of the hook or side tool, at about the vertical angle required for the cutting edge to assume its correct cutting position. In the other direction, the hook is presented to the center of the work, with the stem at a horizontal angle fig. 367; and while cutting the tool is made to swing upon the rest as on a center, describing the curve indicated by the dotted lines, producing a very similar shape in the hollow, to that produced by the gouge. The hook tool sometimes also acquires a slight tilt upon the left under corner of its stem.

Fig. 367. Fig. 368. Fig. 369.

Hollowing With The Gouge Hook And Side Tools 400287

The cut is obtained principally by pressure, and sometimes but in a less degree, by slight leverage or lowering the handle to obtain a trifling alteration in the vertical angle. In turning large work the weight of the body is moderately thrown upon the tool, which then obtains the cut without great muscular exertion. A succession of cuts from the center to the circumference is continued to the required depth, but as this increases, in order to avoid the internal edge of the cylinder, the vertical angle of the shaft necessarily becomes less; sometimes, the rest has to be lowered and the tool held more nearly horizontal, which is much less favourable to its action. The sides of the internal cylinder, left irregular by the gouge or hook tool, may be turned fairly smooth and parallel with the latter. The tool is now supported quite horizontally, grasped by the hands in the manner described for the gouge, fig. 335, the rest being lowered sufficiently to place the cutting edge at, or near to the height of center. The tool is traversed to and fro, with its shaft parallel with the line of the mandrel, slightly tilted on its left under corner, to place the edge in the position for cutting; the shaving being obtained by simple pressure or by slightly twisting the handle to reduce the angle or tilt. The cylinder is frequently tested with the callipers to ensure that it is not turned taper in either direction, and is finished by a series of light cuts taken from the bottom outwards, which leave the sides in fair condition for smoothness, but of necessity with a round corner at the junction of the cylinder with the surface. The rough internal surface, is more or less concave and in rings, but for many purposes this also may be sufficiently corrected with the hook tool.