rotating.

The spindle is moved to and fro by a pivoted lever shown.

Another style of tailstock (not shown) is similar to Fig. 137, but has a cross working slide, in order that facing and similar operations may be effected.

The slide rest, Fig. 139, has concealed screws, as seen, and a swivel base; ball handles are used on the screw ends, though not shown. The tool post is of single screw pattern. A special double type of rest is also employed, having front and rear slides, so that turning, forming, cutting off, &c., can be done without having to change tools. A rest is also fitted

revolves. The swivelling table has a graduated arc, to set to definite angles, and small files, saws, or diamond laps held in the chucks pass through a bush in the table, and rectify hardened work, or perform delicate sawing, &c.

A milling attachment, Fig. 141, bolted to the bed, carries a spindle with division plates, and slides to move this up, and down, and crosswise in both directions. The hollow spindle takes the same fittings as the headstock spindle, so that work already turned may be held in the milling fixture and milled with the aid of cutters gripped in the head.

For cutting threads, an attachment is made

D

for grinding, carrying a small spindle, with endlong movement, and rise-and-fall motion for height of grinding wheel. A rapid unlocking device is fitted, whereby the rest can be run back out of the way, for testing the work, and returned again to position, without affecting the setting. Two other small tool post and rest grinders are used, clamped on the slide rest.

The filing attachment, Fig. 140, is worked in jig-saw fashion, by a face plate on the spindle, the plate being shown drawn off a little in the illustration. A pin in this engages with the jaw of the up-and-down rod of the attachment, and serves to reciprocate it as the lathe spindle

to bolt to the tee slot on the back of the bed. Change gears from the headstock spindle rotate a hob, and this serves to traverse a small slide, after the fashion of the Fox chasing lathe. Many variations are effected by the change gears, and by substituting another hob of different pitch. Various other fittings as faceplates, centres, &c., are employed, and the countershaft is of special design, to provide means for driving the grinding and other attachments.

With lathes of this type almost any piece of fine mechanical work can be tackled, even though it involves operations never done on lathes in the practice of the larger machine

work. Extreme accuracy is attained, by the precision with which the lathes are constructed. For toolroom use they are very handy, in the production of little cutters of all kinds, as well. as for fine mechanisms, gauges, scientific work, gears, models, &c.

Bench Milling Machine.-In fine mechanical work the bench miller plays an important part in conjunction with the bench lathe,-both precision machines of the highest class. The

16 in. in total height, and the slide travels 4 in. vertically, 8 in. longitudinally, and 21 in. crosswise (to and from the spindle). The top table, provided with a central stud, so that it may be swivelled to an angle, has a graduated base, and can be clamped by the two bolts seen. Cross traverse is given by the screw and balanced handle. The longitudinal movement of the knee is effected by a similar handle on the end of the screw which

work performed is generally delicate, and although it may frequently be done upon the bench lathe, with the help of suitable attachments, the miller is more convenient in setting up and operating. Fine mechanisms, small tools, gauges, and experimental work are the chief applications, taking the place by milling of much hand filing and scraping, previously employed in such jobs.

An example of a bench miller, the Sloan & Chace, is given in Fig. 142. This is about

is seen in section between the vertical vees. The nut in which the screw works has also a rack cut upon one side; and a pivoted and handled sector gearing in this allows of rapid movements of the knee, for certain purposes, the nut being disengaged from the knee while the lever feed is in operation. The knee swivels upon the vertical slide, with a divided base, similarly to the table slide. The upand-down motion of the entire slide, &c., is effected by the vertical screw seen, driven

through bevel gears by the handle and inclined shaft.

The hollow spindle has a spring draw-in chuck, which in the illustration is shown holding a cutter arbor. The fittings attached to the table are a vice and a pair of centres (not shown), comprising head and tailstock, the former being fitted with an index plate. These centres are especially useful for cutting small pinions and gears, and for milling cutters, reamers, taps, &c. The dividing head is fitted with a spring chuck also, for convenience of interchanging mandrels, &c., already held in the bench lathe for operations leading up to the milling.

A type of vertical profile miller is also made for the bench, doing fine work of a few inches

trated here, but instead we include a drawing of a combination type, the Parkinson, which is both instantaneous and screw, thus combining the advantages of both. Fig. 143 shows the vice in longitudinal section and end view, from which it will be seen that the thread of the screw, buttress shaped, engages in a movable half-nut. The latter is thrown downwards by clasping the lever A to the shank of the screw; on releasing the lever, the spring B throws a back, and pushes the nut up into engagement with the screw, in which state the vice becomes an ordinary screw type. The jaw may therefore be pushed rapidly up to touch a piece of work, and then screwed tightly against it without loss of time.

The same

B

only in size. The principle of operation is the same as the regular profilers, a pin and slide, controlled by a former.

Bench Planes. The jack, trying, and smoothing planes, because these are always kept for use on the bench, while rebates, rounds, and others are not.

device is employed for wood-workers, but the shape of the jaws is different, see Fig. 144, made to fasten underneath the bench.

Another popular type of instantaneous vice has a cam that pushes forward a block, the teeth of which engage in serrations and draw the jaw along to a certain extent. The chief

Bench Vice. Engineers employ two main forms of bench vice, the ordinary screw, and the instantaneous, the relative advantages of which are a matter of opinion, some men preferring the screw type, notwithstanding that it is rather wasteful of time in operating. The pattern is well known, and need not be illus

not suitable for continued squeezing, or forcing, such as is often wanted in fitters' work, for pushing pins, or bushes into holes, &c. Some vices are made with a swivel jaw, to accommodate tapered work in lieu of the use of taper wedges, inserted between work and jaw. Vices are also made with swivel bases, to revolve on the bench, for convenience in handling long work.

For outdoor work bench vices are often mounted upon portable stands, which must however stand firmly, to avoid annoying shake and rocking. Vices range in size from about 3-in. width of jaw to 8-in., opening from about 3 in. to 12 in. See also Machine Vice, Pin Vice, Tube Vice.

Bench Work. This denotes work done at the bench as distinguished from that which, owing to its size, character, or position, has to be performed away therefrom. In woodwork and fitting and erecting the building-up of a large structure is not bench work, even though it may be done on the floor or trestles adjacent to a bench. The bench work involved is only the preparation of parts at the bench.

In pattern-making a considerable amount of lathe work is often involved, and the pattern - maker consequently gets оссаsional intervals at the lathe, so that in the pattern shop, bench work is generally distinguished as opposed to that done at the lathe. Bench work comprises everything that is done thereon, from the marking out of material to the completion of the work, or the stage at which the portions have to leave the bench for fitting together elsewhere.

provided, and be only laid on the floor for casting. Brass-moulders have always made the greater portion of their moulds on the bench and there is no reason why all light iron-work should not be so done, with increase in the comfort and health of the workman. The practice of machine moulding is favourable to the growth of bench work. Since men stand at machines, they can easily stand also at benches for hand work. Firms now fit up benches more frequently than formerly, when their work

As applied to moulding it distinguishes work done upon a bench from that on the floor. The latter is unavoidable in heavy and medium heavy castings, and then all mending up and detail work done in the mould has to be performed in a kneeling posture. But a great deal more floor moulding is done than is necessary, very many moulds in boxes no larger than 12 to 18 inches square being so done, which might be just as readily made on a bench, if such was

consists largely of light castings. In some foundries the sand floor is dispensed with for a mere casting floor.

Bending Blocks.-The bending block, in the upper part of Fig. 145, pierced with numerous holes, used in the boiler and plating shops, is employed for bending operations, though it is equally adapted for levelling plates, sheets, or correcting sectional forms on; hence also termed a levelling block. The holes are cast for the pur