Document 57:-- J Liberty Tadd, Manual Training Methods in Philadelphia Public Schools

CHAPTER XIII.[page 77]


JOINERY.

SOME of the surfaces of finished joints are more conspicuous and important than the rest. This is true of those surfaces of the joined parts of a picture-frame, which can be seen when the picture is viewed. In such cases, the appearance of the work is improved, if pains are taken to select for those more conspicuous positions the best surfaces of the sticks, to be joined. Conspicuous surfaces of one stick, are often intended to be flush with conspicuous surfaces of the other stick, to which it is to be joined. These may be called the flush surfaces. All of the lines that are drawn, in laying out the work, should have their positions fixed with reference to these flush surfaces. Frequently, one piece is used as a measure or pattern, for determining the dimensions of the parts of the other piece that are to fit it.

Any stick that is to be used in the following exercises, should have its edges made either parallel to or square with one another, before beginning the exercise. The first step to be taken in any of the exercises is to select and mark each of the flush surfaces with an X. Whenever it is desirable to prevent the work from slipping about, hold it against the wooden bench-hook, fasten it in the vise, or fasten it upon the bench with a wooden hand-screw. When cutting cross- grained wood with a chisel, cut diagonally across the grain, in such direction that no splits shall extend into the stick, but all into the chips.


Halving Together.[page 78]

EXERCISE XIII, I. - To halve together two sticks, at their ends. (See Fig. XIII, a.) Mark one stick A and the other B. To mark the flush surfaces. Notice that, as is indicated by the sketch of the finished joint, the top of A is to be flush with the top of B ; a long side of A is to be flush with an end of B; and an end of A is to be flush with a long side of B. Select, and mark with an X, the surfaces of A and of B, that will make the handsomest and best flush surfaces.

To line out the work. Place the try-square upon B, with its beam touching the long, vertical, marked surface, with its tongue upon the top, and with its edge a little less than the width of A from the marked end of B. Place A, right side up, upon the top of B, with one long, lower edge, touching the edge of the square, and with its marked end flush with the marked, vertical side of B Slide A and the try-square, together, along the top of B, until the marked, vertical side of A, becomes flush with the marked end of B. Remove A, and,

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with a sharp knife, line across B, at the edge of the square. Extend this line half-way down each of the long, vertical sides of B. Draw similar lines upon the lower side, and the long, vertical sides, of A, using the upper side of B as a mea­sure, and turning the tops of both pieces downward, in order that the lines may be easily drawn. Set the spur of the gauge at a distance from the head equal to half of the com­mon height of the sticks. Guide the head of the gauge by the upper surfaces of A and B, in turn, and gauge along both of the long vertical sides of each, from the vertical lines pre­viously drawn to the marked ends. Gauge also across the marked ends. Place each stick, in turn, in the mitre-box, or in the vise, or against the bench-hook. Saw across each, with a sharp, fine-toothed back-saw, close to the knife-marks, and down to the gauge-marks. Take care not to remove: with the saw, any portion of either of the knife-marks or of the gauge-marks.


To remove, from A and B, in turn, the wood between the saw-cut and the plane of the three gauge-marks.First method. Place each stick, in turn, on one side, upon a board on the bench, and fasten it with a wooden hand-screw. With a paring-chisel, that is wider than the cut to be made, split or pare off several chips, parallel to the grain. Incline the chisel, so that the chips shall grow thinner as the tool cuts deeper. Incline it so much that the chips shall not split beneath the plane of the three gauge-marks. Let the last cut coincide with the upper gauge-mark. Turn the other side of the stick uppermost and repeat the operation. This will leave a ridge, running lengthwise of the stick. Its lower lines will coincide with two of the gauge-marks. With the wide chisel, pare away the outer end of the ridge. Let the last cut coincide with the gauge-mark at the end. Turn the stick half-way over, bringing the ridge uppermost, and fasten it again with the hand-screw. With a narrow paring 

80 WOOD-WORKING TOOLS. - HOW TO USE THEM.

chisel, bevel away the inner end of the ridge to terminate in a straight line joining the corners where the knife-marks and the gauge-marks meet. Split away, with the chisel, nearly all of the pyramidal ridge remaining. Pare off the rest, and, occasionally, test the surface produced, with a straight edge of the chisel.


To remove, from A and B, in turn, the wood between the saw-cut and the plane of the three gauge-marks.—Second method. Place each stick, in turn, upright in the vise. With a sharp, medium-fine-toothed ripping-saw, cut along the gauge-marks, nearly to the cut made by the back-saw. Finally, pare the surfaces, as when using the first method, or, pare the wider surface, with a small plane that is made for the purpose.

To remove, from A and B, in turn, the wood between the saw-cut and the plane of the three gauge-marks. — Third method. Place each stick, in turn, upright in the vise. With a sharp, fine-toothed ripping-saw, cut, very accurately, close to the gauge-marks, nearly to the cut made by the back-saw. Take care not to cut away any portion of the gauge-marks, and not to saw beyond the knife-marks. Square out the corner with a narrow paring-chisel.

When both sticks have been treated by either method, as has been directed, they will fit together as shown in Fig. XIII, a.


Mortising.

Ex. XIII, a. — To make an open, mortise-and-tenon joint. (See Fig. XIII, b.) Select, and mark with an X, each of the flush surfaces. Mark that stick which is to contain the mortise, A, and the other, B.


To line out the work. Mark the length of the mortise in
A, by laying the try-square, and B, upon it. (See Ex. XIII, I.)
Mark a point, in each edge of the top of A, at the

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edge of the blade of the square, with a sharp knife. Rest the beam of the square upon the top of A, and, with the edge of the blade at each of the points, in turn, make fine knife-marks, on the sides of A, where the end of the mortise will be. These knife-marks should not extend entirely across the sides of A, but they should be a little longer than the thickness of the mortise. Obtain the length of the tenon of B, by laying the try-square, and A, upon it. Line across the top of B with a sharp knife. Rest the beam of the

square upon the top of B, and carry lines down both sides through the ends of the line upon the top. Join the lower ends of these lines, by a straight knife-mark across the bottom, thus lining entirely around the stick. Set the spur of the gauge at a distance from the head of the gauge equal to about one-third of the thickness of either piece. Rest the head of the gauge upon the top of both pieces, in turn, and gauge along the sides, as far as the cross-lines previously drawn. Gauge, also, across the flush ends of both pieces.

8 2 WOOD-WORKING TOOLS. - HOW TO USE THEM.

Then set the spur at a distance from the head equal to about two-thirds of the thickness of either piece, and gauge along the sides and across the ends, of both pieces, near the other gauge-lines.


To remove the superfluous wood from the tenon. Notice that the shape of that part of the stick, which is to be re­moved from either side of the tenon, is like that which was removed from the sticks that were halved together in Ex. XIII, I. Remove, then, the superfluous wood, by either method of that exercise.


To remove the chief part of the superfluous wood from the mortise. — First method. Place A upon a board, upon the bench, with one of its sides uppermost, and fasten it there with a wooden hand-screw. Take a mortising-chisel which is, about an eighth of an inch, narrower than the thickness of the mortise. Rest its cutting-edge upon the wood to be removed, at about a quarter of an inch from the flush end, and with its centre upon the centre of the thickness of the mortise. Hold the straight face of the chisel upright, and next to the flush end. Take care not to tip the chisel sidewise. Drive the chisel in with a mallet. The bevelled side of the chisel will cause the chisel and the chips to work out through the open end of the mortise. Take each succeeding cut nearer to the blind end of the mortise, the last one beginning at about one-eighth of an inch from that end. Do not cut closer to the blind end than one-eighth of an inch. Turn the stick the other side over. Fasten it, again, with the hand-screw. Cut, as before, from the side now uppermost, begin­ning the last cut from this side at about one-eighth of an inch from the blind end. Next, turn the chisel around so that the bevelled face is next to the flush end. Hold the chisel verti­cal and trim nearly to the end of the mortise.


To remove the chief part of the superfluous wood from the mortise.— Second method. Place the stick upright in the

JOINERY. 83

vise, and, with a medium-fine-toothed saw, saw just within the gauge-marks, on both sides, nearly to the blind end of the mortise. Take care not to remove any part of the gauge-marks or of the knife-marks, with the saw. — With a sharp, narrow mortising-chisel, remove the wood that is between the saw-cuts.

To remove the chief part of the superfluous wood from the mortise. — Third method. With a bit, of a diameter that is a little less than the thickness of the mortise, bore a number of holes, in regular succession, entirely through the mortise, as in Ex. XII, 2, or Ex. XII, 3. Begin near the open end of the mortise.


To remove the chief f part of the superfluous wood from the mortise.— Fourth method. With a bit, of a diameter that is a little less than the thickness of the mortise, bore a single hole, entirely through the mortise, near its blind end. Make two saw-cuts, as in the second method.


To finish the mortise, having removed the chief part of the superfluous wood, by either one of the four methods. With a paring-chisel, of the same width as the mortising-chisel, square out the blind end and bevel the sides to terminate in a straight line joining the corners where the knife-marks and the gauge-marks meet. Then, with a wide paring-chisel, bevel the sides and the outer edge of the mortise until the bevels terminate in the gauge-marks. Then split and pare, to the planes of the gauge-marks, as in Ex. XIII, I.


To remove the superfluous wood from the mortise.—Fifth method. Place the stick, upright, in the vise, and, with a sharp, fine-toothed back-saw, saw, very accurately, close to the gauge-marks, just within them, on both sides of the mortise, and near to its blind end. Take care not to remove any part, of the gauge-marks, or of the knife-marks. With a sharp, narrow mortising-chisel, remove the chief part of the wood that is between the saw-cuts. With a sharp, narrow paring 

84 WOODWORKING TOOLS. HOW TO USE THEM.

chisel, that is a little narrower than the thickness of the mortise, square out the blind end of the mortise, to the lines.

Ex. XIII, 3.— To make an open, double, mortise-and-tenon joint. (See Fig. XIII, c.) Make the thickness of each mortise and tenon about one-fifth of the thickness of the sticks. Proceed otherwise, as in Ex. XIII, 2.

Ex. XIII, 4. — To make a mortise-and-tenon joint. (See Fig. XIII, d.) Select, and mark with an X, each of the flush surfaces. Mark the stick that is to contain the mortise, A, and the other, B.

To line out the work. — Lay the stick, A, upon the bench, with its top uppermost. Place the blade of the try-square upon the top of A, in such position that its edge shall be directly over the intended position of one end of the mortise. With a sharp knife, mark a point in each edge of the top, at the edge of the blade. Without changing the position of the

JOINERY. 85

edge of the blade, rest B upon A, with its top uppermost, with its flush end flush with the flush side of A, and with one of its lower edges touching the edge of the blade. Mark a point, in each edge of the top of A, at the lower edge of B, and over the intended position of the other end of the mortise.

Square down from each of the four marked points, in the top of A, and make four knife-marks, of the proper length, upon the sides of A, where the ends of the mortise will come. Find the length of the tenon of B, and line entirely around, at the inner end of the tenon, as in Ex. XIII, 2. Gauge the sides of the mortise and tenon, as in Ex. XIII, 2.

To remove the chief part of the superfluous wood from the mortise. First method. Bore a number of holes, entirely through the block, in regular succession, as in Ex. XII, 2, or as in Ex. XII, 3.

86 WOOD-WORKING TOOLS. —How TO USE THEM.

To remove the chief part of the superfluous wood from the mortise.Second method. With a sharp, mortising-chisel, that is a little narrower than the end of the mortise, cut deep and across the grain, at about one-eighth of an inch from one end of the mortise. Hold the chisel upright, and with

its straight face toward the nearer end of the mortise. On withdrawing the chisel a gap is left in the wood, as in Ex. III, 4. Carry the chisel a short distance toward the farther end of the mortise, and cut again into the wood. The bev­elled edge of the tool will cause both the tool and the chip to work out into the gap. Repeat this process until the gap has been sufficiently enlarged. Then turn the piece the other side up, and meet the first gap by a similar one from the other side. Next, proceed to finish the mortise, as in Ex. XIII, 2.

To remove the superfluous part of the wood from the mor­tise.Third method. Bore one hole entirely through the wood and near the end of the mortise. Pass a narrow saw-blade, (such as a gig, fret, or key-hole saw-blade,) through the hole, and saw out the superfluous wood along both sides, and across the further end, of the mortise. Whichever method is used to remove the chief part of the wood, finish with two paring chisels. One should be a little narrower than the sides, and the other a little narrower than the ends, of the mortise. First, with the narrower chisel of the two, square out the ends of the mortise, to the knife-marks, and bevel the sides, to terminate in straight lines joining the cor­ners of the ends. Then, with the wider chisel, bevel the sides, to the gauge-marks. Finally, split away the ridge and pare to the plane of the gauge-marks, with the wider chisel ; testing the accuracy of the work with a straight edge of the chisel.