Plain turning in wood and ivory has so wide a range, that illustration by examples can necessarily indicate but few of its results. The indulgence of the reader is therefore claimed for the attempt made in the following chapters, as also for the short preceding references to construction and design; which, serviceable to beginners, must in many points be already appreciated by the practised amateur. The series of typical designs offered, presents no difficulties, but gradually increasing elaboration in form and manipulation; and it is hoped may also serve as suggestions, to be carried out in other shapes as individual taste may determine.
In simple plain turning, the work revolves and is entirely executed upon one axis. The specimen may be produced from a single piece of material, or it may be constructed of many pieces, perhaps of several contrasting materials, all its parts still possessing one common axis or center; the entire work may be of the plainest character, or it may be distinguished by elegance of form, or enriched by ornament. Combined plain turning, to which the succeeding chapter is devoted, may be divided into specimens formed by a central principal and axial figure, into which turned ornaments or subordinate parts are inserted eccentrically; and into those in which the solid itself is turned from two or more axes, for the production of surfaces, ornaments or projections at various angles to the main axis.
The combination of many pieces in simple plain turning is frequent and necessary ; for economy of material, convenience in construction and manipulation, for strength, and for contrast in color. Small and moderate sized works, when no contrary reason exists, are however often advantageously made from a single piece as one solid; but when the work presents any considerable variations in diameter, and is of large or even moderate size, it is generally necessary to construct it of two or more pieces fitted one into the other or screwed together, as will be shown.
All the above mentioned reasons it may be said, have about equal force in determining whether the entire work should be turned in one or in several portions; and if in the latter, as to whether its main subdivisions should themselves be constructed of one or more pieces. The increase in stability attained by chucking the work as several short lengths instead of in one long piece, greatly conduces to the production of smooth and well finished surfaces. Separation into parts, generally permits greater freedom in the management of the tools, which otherwise often have to be restrained and are with difficulty prevented from encroaching upon neighbouring portions of the work; while the short lengths of the individual pieces very frequently enable the popit head to be dispensed with. In forms, such as figs. 633. 663, and others, where portions of the work of comparatively large are connected by those of small diameter, the neck or connecting piece when turned from the solid is more or less deteriorated and weakened by the strain it suffers in the process; diminished diameters in such positions are therefore much stronger, when turned upon one only of the two large diameters and attached in an aperture turned in the other; or sometimes, the smaller portion may be turned as a separate piece to be affixed to both its neighbours. Lastly the comparative rarity of hardwood and ivory of the larger diameters, makes it desirable to economise these by employing portions of no greater length than is essential to the design.
It should also be remarked, that some among the following subjects are relatively of large and others of small size, this circumstance, together with the limited space at disposal, does not allow of the entire series being drawn to the same scale; but as every figure exhibits its due proportions, the variation may perhaps be considered as of less importance. All are taken from a tabulated list, placed at the end of this section, possibly convenient as a collection of works of utility or ornament produced in the lathe; most possess the former characteristic, and while it is premised that all are intended to elucidate modes of procedure, rather than to serve as models of form, it is hoped that none may offend good taste. While, without assuming to lay down canons on so inexhaustible a subject, this chapter can hardly be passed over without using the same examples, in hazarding a few words upon form and ornament and their appropriate application in plain turning.
In the production of any specimen marked by good taste, the elements of success are found to lie in the adoption of simple proportions in the section or outline of the main figure; followed by a co-relation to this form in the details of a subordinate ornamentation; which together, give a homogeneous, natural character to the design. In turning however, the outline is often and correctly influenced by the appropriateness of the form to the purpose to which the work is to be applied; and secondly, the proportions that appear most desirable may have to submit to variation, to be more or less recast, by reason of imperfections or of want of sufficient size in the material, either of which may only become apparent during the progress of the work. The former of these contingencies need but rarely interfere with an agreeable shape; and the latter may be overcome, in the infinite gradations that may be given to the principal curves forming the outline, which in almost every case will submit to variation in depth or curvature, height or breadth, and still remain elegant. A convenient property, in great measure neutralizing any ill effect the accidents of the material might otherwise exercise over beauty of form, and affording scope for ingenuity and taste, to satisfactorily vary the original proportions of the design.
Correct balance or proportion between the principal curvatures of the outline, differing as it does with every individual figure, cannot be easily defined, but inappropriate form and the class of error to be avoided may be broadly indicated. Thus, it is evident that the graceful, tapering curve of an amphora, employed in fig. 700, or the outlines of any of the vases, figs. 670 to 678, would be destroyed by the superposition of secondary, quicker and abrupt curves, merging into the first at any part of their length ; but on the other hand, such curves becomes appropriate as part of the bowl of a chalice or tazza. The lower portions of any form it is equally apparent should be of sufficient magnitude to convey a feeling of stability, and yet not so extended as to appear unduly heavy; while cornices and other projections towards the summit, poor and feeble, when too slight in depth or width, become in most cases equally ungraceful when too far extended in proportion to the foot or to the body of the work from which they spring. On the other hand, many among the illustrations exhibit the extent to which the curvature of the main outline may sometimes rapidly taper from a large to a small diameter, without giving the effect of weakness, and others, that to which lips and similar projections may occasionally extend. Artistic feeling demands a balance in the form of every figure, but so arbitrary are the curvatures that may be successfully adopted that the elegance or otherwise of the outline produced, must always in great measure depend upon the taste and knowledge of the operator; with results more successful from one hand than another in corresponding degree.