Woodwork and mechanical drawing

TO THE TEACHER

MANUAL TRAINING as a school study has successfully passed the stage of experimental teaching and reached a recognition that requires neither defense nor apology. But there remains, as in all school work, a distinct necessity for relating it to the every-day needs and desires of the child, not so much the young child as the developing child in his teens. To meet these needs by stimulating inquiry and promoting activity along the line of directed work is the aim of the author. The desire for the beautiful is also met by the large number of projects offered, among which the pupil is left free to select the ones he admires for construction. Mechanical drawing is a necessary adjunct of good manual training; the eye must aid the hand in the task set by the brain. The exercises presented are designed to promote that skill which in time would make the youthful worker able to select and prepare his own drawing and to apply his knowledge to any problem he may encounter.

Tools, hardware, stains, waxes, and lumber, in so far as they come under the observation of the young student, receive mention. No attempt has been made to formulate a hard and fast text; on the contrary the natural limitations incidental to widely differing school districts have been kept in mind. It is hoped the teacher will not only permit but encourage the greatest possible freedom of choice in selecting the task.

Saws may be divided into two groups; first, power saws, such as band and circular saws; second, all kinds of hand saws. The second group is used in manual training. They are classified as follows:

(1) The Cross-cut Saw, for cutting across the grain of the wood. The teeth of this saw are sharp pointed, Fig. 1, and act like so many knives cutting a double knife line across the board. The sharp point cuts, and the body of the tooth tears out the wood between the knife lines.

(2) The Rip Saw, for cutting in line with the grain of the wood. This saw has chisel-pointed teeth, Fig. 2. Each tooth cuts like a small chisel. A rip saw must be used in line with, not across, the grain of the wood.

(3) The Back Saw, for fine, accurate cutting and fitting. This is a cross-cut saw with a steel back to stiffen the blade. It has very small teeth, which are not set, but depend for their clearance upon the wire edges left by the file in sharpening; may be used for either ripping or cross-cutting.

(4) The Turning Saw, for circular and irregular shaped cutting. This saw has a blade 12 or 14 inches long, and from 1/8" to 1/16"  wide, with rip saw teeth, and adjustable handles. The frame is wood, with an iron or rope tie-bar.

(5) The Coping Saw, for circular and irregular shaped cutting of thin boards. This saw has a narrow blade about 32" wide, with small teeth, and a metal frame.

It is very important that a saw should be set correctly, that is, it must cut easily without binding. A saw that is properly sharpened must be set with every alternate tooth projecting to one side. The other teeth must be bent slightly in the opposite direction, Figs. 1 and 2.


EXERCISE IN LAYING OUT AND SAWING

1. Measuring from one end of the board, lay out the length given by the instructor. Use a two-foot four-fold rule and lay on edge so that the divisions on the rule are against the boards, Fig. 3. This is the correct way to use this type of rule for accurate measuring.

2. Place handle of try square against one edge of the board and with pencil mark across the board, Fig. 4. Mark in this manner all boards which are to be squared. Never saw a board without first drawing a line. In ordinary work a good test of accuracy is to saw this line completely out; that is, it should not show anywhere after the cutting is completed.

3. Lay the board on top of the bench with line to be sawed outside the edge of the bench. If the board is a short piece, place it in vise instead of on top of the bench. The weight of a long board held by the hand secures firmness so that a vise is not needed.

4. Start the saw by drawing the first few strokes towards the body. Then push steadily away along the marked line, Fig. 5. Do not press down on the saw ; it cuts on the for- ward and not on the backward stroke.

5. Set the marking gauge at the width given by the instructor. Mark this width on board, Fig. 6.

6. Place board in the vise, and with a rip saw cut along the line,

1. Study carefully the drawing of the plane and its parts, Plate 1. Note the lateral adjusting lever, adjusting nut, the frog, the Y adjustment, the plane iron, cap iron, cap, the double plane iron (which is the plane iron and cap iron together), the knob, and the handle.

2. To sharpen the plane take apart and remove the double plane iron. Loosen the cap iron screw which holds the plane iron to the cap iron. The plane iron is the only part which is sharpened. If the bevel on plane iron is too rounded or too short from sharpening on oil stone very often, have it ground again. The bevel should be about 25 degrees or T y to 14" long.

3. Grinding - Place the plane iron against a tool rest set at a distance suitable to obtain the bevel wanted, Fig. 8. The tool rest shown is a strip of wood nailed to the grindstone frame. Grindstones having cast iron frames sometimes have adjustable tool rests. Hold the plane iron against the stone with both hands and grind the edge square and straight. The safe way is to have the stone turn away from you, though it cuts much faster when it is turning toward you, which is the way mechanics use it.

4. Oil Stoning - Grinding does not sufficiently sharpen a plane; it only gives the correct bevel. To sharpen a plane iron hold in both hands on the oil stone at the same angle as the bevel of the plane iron, and rub on the stone, Fig. 9, until you raise a feather or wire edge, that is, until you can feel the metal turned over on the straight side of the plane iron. Do not make the feather edge large, as it is unnecessary. Press harder on each edge in order to round the corners a trifle so as not to dig into the wood and cause ridges. Turn the plane iron over and hold perfectly flat on the straight side and rub, Fig. 10, until the feather edge disappears on that side. You will be able to feel it on the beveled side now. Turn the plane iron over again on the beveled side and rub a few strokes. Continue these operations until the feather edge disappears entirely. Feel for it on both sides, but be careful not to cut your fingers.

5. Adjusting the Plane - The adjusting nut is for gauging the thickness of the shaving the plane is to cut. An easy way to set a plane is to draw the plane iron up by means of the adjusting nut until it is even with the bottom of the plane. Then carefully turn the adjusting nut while moving the plane across the board until the shaving is of the proper thickness. If the plane cuts on either edge of the blade instead of the center, turn the lateral adjustment toward the edge that it is cutting until the shavings are being cut in the middle of the plane iron. Always cut very thin shavings, and have your plane sharp.