Introduction

The great diversity found in the form, size and materials, of works executed in the lathe, has led to the production of a corresponding variety in the chucks and appliances used for fixing. Necessary to meet the requirements of works that may be long or short, large and heavy, or small and delicate in character; simple or complex in form, and also, as they may be in their first rough or final and finished stages.

Lathe chucks, may nevertheless be divided into two principal groups; the first for long works, those in which the length is several times the diameter; the second for short works, in which the diameter is several times the length. Each of these groups, may be subdivided for convenience of arrangement, viz., into

Section I. Chucks for long objects supported at both ends. ,, II. ,, ,, ,, ,, at one end.

,, III. Chucks for short objects, grasped by their edges. ,, IV. ,, ,, ,, fixed against one of their surfaces.

Without attempting the difficult and perhaps unnecessary task, of collecting all the numerous contrivances, that may have been used for every different purpose, the more general and useful of the chucks under each head, will be described; and it will be seen that these comprehend a wider range of work than would probably be required by any one individual or establishment. Many of the chucks are nearly duplicates, while some different forms, apply to the same purposes. These varieties are very valuable, permitting a choice of method of carrying the work; the selection of that most appropriate,

Section I. Chucks For Long Objects Supported At Both Ends; The Popit Head Always Required

PHONG Chuck . . .189 FLANGE Chuck with Points 190 TAPER FLUTED Chuck . 191

For solid blocks of wood, much used for large and small common works, for toys, and also for preparing material for other chucks.

SQUARE-HOLE Chucks . . 191

For smaller solid pieces of wood, ivory and metal, of less size than, the above and squared at one end. Much used in metal, for screws, spindles and other objects in which the centers are not required after completion, -for general purposes and for preparing work for other chucks-Centering and setting the work for the Square-hole and other chucks-Centering tools.

DKIVER OR RUNNING-CENTER Chucks . . . 196

VARIOUS CARRIERS used

WITH THE ABOVE . . . 197

CLEMENTS and other DOUBLE-DRIVER Chucks. 200

Extensively and exclusively used for metal works ; in which the centers are to be retained - Clements chuck, for the correction of an incidental error.

Scribing tools, and centering works turned from many centers, as cranks, eccentrics - works at right angles.

Section II. Chucks For Long Objects Supported At One End; The Popit Head Occasionally Used

SQUARE-HOLE Deill Chuck 205

PAD Chuck..... 205

BORING BIT Chuck . . 206

ROUND-HOLE DRILL Chuck 206

ARBOR Chuck foe Cieculae Cuttees .... 207

Carrying drills, bits and countersinks-for works in wood or metal at rest and advanced by the popit head- for notching joints, screwheads, and for ornamental carving by hand.

HOLLOW Chucks with PINCHING SCREWS . . 207

DIE Chuck with Two Slides 208

DIE Chuck with One Slide 209

BENNETT'S DIE Chuck . . 210

MORDAN'S „ „ . 211

BEACH'S „ . . 212

DIE Chuck with Split Dies 213

Possessing the power of contraction, for short cylindrical and other pieces of wood and metal; assisted by the popit head for long works.

The Screw chucks sometimes of considerable diameter - the Die chucks with slides, have radial adjustment for concentric or eccentric chucking-the Mordan and Beach chucks for wires and drills and small concentric work -Split dies for fixed diameters and arbitrary shapes.

Section III. Chucks For Short Objects Supported By Their Edges

METAL PLAIN, CUP, OR DRIVING Chucks . . 214

WOOD Plain Chucks . . 216

WOOD „ „ with

METAL SCREWS . . 216

ARBOR Chucks . . . . 221

Conical driving chucks without loose parts ; for rough pieces of wood rounded with the paring knife or turned circular ; the work driven in or upon them by slight blows. The wood chucks turned to the diameter of the work-Arbors, principally metal, for hollow works - Metal chucks filled with wood or lead.

WOOD SPRING Chucks. . 222

METAL „ . . 223

BENNETT'S „ . . 225

EXPANDING MANDRELS. Brunels, Hicks, Yuiles, Le Counts and Double Cone...... 226

Provided with a small power of central contraction or expansion, for more delicate purposes than the driving chucks. The wood chucks turned to the diameter of the work, the work turned to that of the metal chucks and nearly to that of the arbors.

UNIVERSAL Chucks with Two, Three or Four Slides 229

SURFACE Chucks with Dogs 234

Chucks for wood and metal of various constructions, with considerable power of simultaneous adjustment for contraction and expansion - used for circular objects held from within or without -for square and other pieces - Some chucks with independent adjustment.

Section IV. Chucks For Short Objects Fixed Against One Of Their Surfaces

STEEL-WORM Chucks . . 236

DOUBLE SCREW Chucks. . 237

ARBOR Chucks with Nut and Washers . . . 238

ARBOR Chucks with Cone . 238

WILLIS' DISC Chuck . . 238

Fixing the work by one central screw - for wood principally plank-ways. For numerous wood, ivory and metal works attached to each other by screws also fitting the screws of the chucks. The Arbor and disc chucks for the completion of works pierced with central apertures.

CEMENT Chucks for Wood and Metal .... 239

SURFACE Chucks for Wood attached by screws and Washers..... 240

SURFACE Chucks for Metal with Clamps and Bolts . 242

Largely used for comparatively thin works in wood and metal,-different methods of centering - Various different methods of attaching works to the surface chucks, - counterpoise to eccentric work.

UPRIGHT WOOD Chucks . 248 UPRIGHT METAL Chucks . 251

For rectangular works in wood, ivory and metal - angular varieties concentric and eccentric - Apparatus attached to the metal chuck for analogous larger works. Chucking blocks, used for carrying work at right and other angles to its previous position on the mandrel.

being generally a question either of comparative accuracy or facility. On the other hand, however extensive the collection of chucks, it constantly happens that none are precisely suitable to the work in progress, which, presenting some peculiarity in form, requires either a modification to be made in one of the chucks already possessed, when such occasional alteration presents no difficulty, or otherwise, the construction of a new chuck of a suitable character.

The chucks run absolutely true, only upon the one lathe mandrel upon which they have originally been made; and they do not admit of being changed from one lathe to another, even when the screws of the mandrels are made as nearly as possible to the same size. Should it happen moreover, as is occasionally the case, that one or two chucks out of a series, run nearly equally well upon two different mandrels, the degree of inaccuracy of the remainder, is equally a matter of uncertainty. The want of truth shown by a chuck when placed upon another mandrel, is usually greater and more visible edgewise than upon the surface, and the central point of the chuck, instead of revolving exactly upon itself, revolves describing a small circle, varying according to the degree of error. It is therefore indispensable that all the center chucks pointed or otherwise, and all chucks requiring accuracy, should be fitted and turned true in their place upon their own mandrels; but it will also be observed, that a few of the chucks are always turned out true to fit the work, with these therefore except for appearance, the external want of truth is not of so great importance.

The sets of metal chucks usually vary in number, from about nine to thirty, among which several sizes of the simpler kinds should always be included; the variety or class of chucks and their dimensions, being in accordance with the particular lathe and the purposes to which it is devoted. The chucks enumerated in the foregoing tabulated list apply, some exclusively to wood, others only to metal, while some are employed for either; their names are accompanied by short notes on their general application, with references to matters in connection, which latter, together with the practical use of the different chucks, are described in the four sections of this chapter.