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CHAPTER XXV.

HAND-POWER MACHINES.

ONE of the most general operations in joinery is that of mortising, and there are few but the very smallest establishments that cannot employ a machine driven either by steam or hand economically. It is a matter of some doubt when a machine for mortising was first made in this country. Probably rotary machines driven by water power were in use at the end of the last century. However that may be, Bentham in his specifications in 1793 distinctly claims both reciprocating and rotary machines; and it seems that he, in connection with his brother, Jeremy Bentham, was commissioned some few years later by the Government to fit up several of the dockyards with machinery, amongst which mortising machines are mentioned. In the first thirty years of this century little or no progress was made, and very little appears to have been done in manufacturing machines for sale. Even in the year 1848 the manufacture was confined to a very few firms in this country, amongst which we may name the following as the most important :-Worssam, London; Horn, London; Powis, James, and Co., London; Robinson, Rochdale; Furness, Liverpool; McDowall, Johnstone; Forrest and Barr, Glasgow; and most of these

[graphic]

FIG. 38.-HAND-POWER MORTISING AND BORING MACHINE.

When we compare

made only on a very small scale. the large establishments now in operation, and the great range of machines turned out, we cannot but admit that sawmill engineers have, to say the least, kept pace with any other branch of engineering.

A mortising machine worked by the foot was invented by Mr. John Mortimer, of Aberdeen, in the year 1847; and the hand-power lever mortising machine was introduced into this country from America by Mr. Coulson, of York, about the same time.

The mortising and boring machine we illustrate herewith (fig. 38), although somewhat modernised, is substantially the same as one brought out by Messrs. Wilson and Lewis, for the firm of Powis, James, & Co., in the year 1852, and for the combination of the operations of mortising, tenoning, and boring in one machine letters patent were granted to them. The illustration does not show the tenoning arrangement, which, however, is easily added. As a strong, well-made machine it compares favourably in the ratio of six to one against hand labour with chisel and mallet; the wonder is, in these high-pressure days of cheap production, that they are not more universally used than they are, as they would pay a handsome interest on the amount invested if they were idle one-half of the year.

The action of the machine is easily understood. Motion is given to the chisel by a counterbalanced forked lever (worked by one or both hands), which is connected with a gun-metal cross-head at the top of the vertical spindle by two wrought-iron double eye-pieces. The wood to be mortised is placed on a table immediately beneath the chisel. This table can be worked by the large hand-wheel, which is perhaps the most

convenient for light work, but for heavy work a selfacting arrangement can be used with advantage. This self-acting motion is gained by a side rod from the forked lever, acting by means of a stop-piece on another small weighted lever, at the end of which is a wroughtiron paul, acting on a toothed wheel which is fixed to a spindle. A pinion on this spindle works in a rack beneath the table; thus, when the forked lever is in work, a lateral motion is given to the same. It is easily thrown out of motion when not wanted by moving the stop-piece. The chisel used is of solid cast steel, tapered somewhat on back and sides, which, after trial of hollow and many other forms, is undoubtedly the best for all practical purposes. It has a plain tapered end fitting into a socket. Some makers fit a 'feather' on to their chisels, with the idea of always keeping them square to the work.

This I do not recommend, as after a time the 'feather' is apt to get loose or twisted. Forked or double-mortise chisels have also been tried, but without much success. This machine is adapted for doing any kind of mortising in soft or hard woods; in the latter, however, it is necessary a hole should be bored in the line of mortise to clear the chisel. It can be worked by unskilled labour, hence its great practical value in the Colonies as well as at home. In fixing the chisel to commence work, press it up in its socket; making a light indentation in wood, reverse chisel, and bring same down again, and note that it falls square between gauge-lines. In wedging a mortise, it is only necessary to raise one end of wood and make the wedge cut before removing same. To take the jar off the cross-head at the top of vertical spindle (which is cou

siderable in hard wood) an india-rubber washer about an inch in thickness is fitted on spindle immediately beneath it. The boring motion needs no explanation, it consisting merely of a pair of bevel wheels worked by a handle which gives a rotary motion to the spindle, and an auger is inserted in the spindle socket in place of a chisel. The tenoning arrangement consists of a pair of adjustable bevelled knives, fixed to a forked tool-holder, fitted into the chisel socket, and working in a slide fixed to the table.

The operation is the same as for mortising; the wood, however, is cut away on the edges, and the tenon is left in the centre. Tenons can be cut rapidly in this manner, but great care is necessary to keep the knives in order, as they are, even with careful management, apt to spring, thus cutting an untrue tenon, thicker at the bottom than at top. When mortises or tenons have to be cut or holes bored at an angle, the table which holds wood can be arranged to cant and fixed to any angle desired; by means of a quadrant and pointer worked by a worm and worm wheel, it can also be made to rise and fall when the work varies very much. Some few machines worked by the foot are in use; they may auswer tolerably for very light work, but for the general rough work of a builder's establishment they are of little value.

In 1861 Mr. Jackson, of Leeds, patented some improvements in the method of operating hand-lever mortising machines.

In the year 1876 Mr. John Phillips, of London, patented some improvements in hand mortising machines, the chief of which was the mounting of the hand lever at the upper end of a rocking fulcrum bar.

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