The two side screws c, d,constitute with the the chop e, a kind of vice screw c, simply compresses, the screw d, has a piece f, called a garter (shown detached), which enters a groove in the cylindrical neck of the screw d, so that when the screws are both opened, d serves to bring the chop e outwards. The chops are greatly used for fixing work by the sides or edges, and as they open many inches, small boxes, drawers, and other works, may be pinched between them.

There are other constructions of benches which it is unnecessary to describe; some have only one of the screws c, d, the other being replaced by a square bar fixed in e, and many are not furnished with the end screw g, which draws out the sliding piece h, that is very carefully fitted. The end screw serves also as a vice for thin works which are more conveniently held at right angles to the position of the side screws; but its more valuable purpose is for holding work by the two ends, which mode is exceedingly convenient, especially in making grooves, rebates, and mouldings, as the work is in no danger of slipping away from the tools. There are several square holes along the front of the bench, for an iron stop i, which has a perpendicular and slightly roughened face, and a similar stop j, is also placed in h, and as the latter slides a quantity not less than the interval between the holes, pieces of any length below the longest may be securely held.

For holding squared pieces of wood upon the bench, as in making mortises or dovetails, the holdfast k, is used in the manner shown, it is an L formed iron, the straight arm of which fits loosely in a hole in the bench; the work is fixed by driving on the top at k, and it is released by a blow on the back at /. Sometimes also the holdfast is made in two parts jointed toge-ther like the letter T, with a screw at the one end of the transverse piece, by which the work can be fixed without the hammer, but the former mode is far more common and is sufficiently manageable. And m is a pin which is placed in any of the holes in the leg of the bench, to support the end of long boards, which are fixed at their other extremity by the screws, c, d. We will now proceed to the management of the planes. See

Appendix, notes A K, A L, and A M, pp. 978 and 980.

Of the bench planes enumerated in the list on page 476, the following are most generally used, namely, the jack plane for the coarser work, the trying plane for giving the work a better figure or trying its straightness and accuracy, and the smoothing plane for finishing the surface, without detracting from the truth obtained by the trying plane. Sometimes when the wood is very rough and dirty, two jack planes are used still more to divide the work, and these instruments are managed in the following manner.

The remarks on pages 477-8 explain that, for long planes, the iron is released by a blow of the hammer on the top of the plane at the front; the smoothing, and all short planes, are struck at the back of the plane, and never on the top, or the wedge may be tapped sideways, and pulled out with the fingers.

The top iron is then removed, by loosening the screw, and sliding it up the mortise, until its head can pass through the circular hole in the cutting iron.

The plane iron having been ground to an angle of some 25 degrees, with the stone running towards the edge, it is next sharpened at an angle of about 35 degrees on the oilstone. The iron is first grasped in the right hand, with the fore finger only above and near the side of the iron, and with the thumb below; the left hand is then applied with the left thumb lapping over the right, and the whole of the fingers of that hand on the surface of the iron; the edge should be kept nearly square across the oilstone, as when one corner precedes the other the foremost angle is the more worn.

When the iron is required to be very flat, as for the finishing planes, the surface of the oilstone should be kept quite level, and the blade must be held at one constant angle; but when it is required to be round on the edge, a slight roll of the blade is required edgeways; lastly, the flat face of the iron is laid quite flat on the oilstone, to remove the wire edge, and if required, the edge is drawn through a piece of wood to tear off this film, after which the iron is again touched on the oilstone, both on the chamfer and flat surface, as the edge when finished should be perfectly keen and acute.

The iron is frequently held too high to expedite the sharpening; it is clear, that should it be elevated above 45°, or the pitch of the plane, the bevil would be in effect reversed, and it could only act as a burnisher; exactly at 45° the keen edge would be soon worn away, and the condition of the burnisher would remain; and, within certain limits, the lower or thinner the edge is sharpened the better. Perhaps the angle of 35° which is assumed, is as favourable as any, as if the edge be too acute the durability greatly decreases, and therefore Some regard is also shown to the degree of wear and fatigue the iron is called upon to endure.*

The edge of the iron is likewise ground to different forms according to the work; thus, the jack plane is found to work more easily when the iron is rounded as an arc, so that whether it project in the center more or less than one-sixteenth of an in the common measure, the angles of the iron should sink down to the sole of the plane at the corners of the mouth.

The ease thus afforded appears more or less due to three causes. The rounded iron makes its first penetration more easily, as it commences as it were with a point, or very narrow edge: the iron has to penetrate the wood as a wedge, first to cut and then to bend the shaving; and it is likely that the reduction of labour in the cutting, by the narrow portion of the edge being employed, is greater than the increase, in bending a thicker but narrower shaving; and lastly, the curved iron distantly approaches the condition of the skew-iron, and in all inclined blades then is a partial sliding or saw-like motion, which is highly favourable cutting. The irons for the finishing planes, although sharpened as flat as possible at other parts, arc faintly rounded at the corners to prevent their leaving marks upon the wood.