Read Ebook: Essentials of woodworking by Griffith Ira Samuel Lawrence Edwin Victor Illustrator

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Ebook has 374 lines and 38780 words, and 8 pages

INTRODUCTION.

Care of tools and bench 3

TOOLS AND ELEMENTARY PROCESSES.

SIMPLE JOINERY.

WOOD AND WOOD FINISHING.

TOOLS AND ELEMENTARY PROCESSES.

LAYING-OUT TOOLS--THEIR USES.

The rule should not be laid flat on the surface to be measured but should be stood on edge so that the knife point can be made to touch the divisions on the rule and the wood at the same time. Fig. 2.

Whenever there are several measurements to be made along a straight line, the rule should not be raised until all are made, for with each placing of the rule errors are likely to occur.

The rule is used to find the middle of an edge or surface by placing it across the piece so that the distances from the edges of the piece to corresponding inch, or fractional marks shall be the same, Fig. 3, the middle of the piece being at a point midway between the marks selected.

The try-square is used for three purposes: First, to act as a guide for the pencil or knife point in laying out lines across the grain at right angles to an edge or surface; second, to test an edge or end to see whether it is square to an adjoining surface or edge; third, to test a piece of work to see whether it is of the same width or thickness thruout its entire length.

Fig. 5 shows the various positions assumed in lining across a piece. The beam should be held firmly against either the face side or the face edge.

If the beam projects beyond the end of the wood, it should be reversed. The knife should be inclined forward and away from the blade of the try-square slightly. A light, firm line should be made the first time across the piece.

In testing edges or ends for squareness, the beam should be held, as in lining, firmly either against the face side or the face edge. Fig. 6. Care should be taken to test the extreme ends of the piece. Also test at a sufficient number of points to show fully the condition of the edge. Sliding the try-square along the edge is not objectionable if the blade be held lightly on the surface. Under no circumstances should the try-square be used to scrape the wood.

In testing a piece to see whether it is of the same width or thickness thruout its entire length, place the blade across the surface to be tested, holding the beam lightly against the face side or face edge, slide the try-square along the piece with the eye fixed upon the graduations at the outer edge. Fig. 7.

There are various ways of setting the bevel to the required angle. Should the triangle used in mechanical drawing be available, angles of 30 degrees, 45 degrees and 60 degrees are easily obtained by adjusting the bevel to the sides of the required angle.

To set the bevel to 45 degrees by means of the framing square, hold the beam against one of the arms, Fig. 10, and move the blade so that it shall pass through corresponding points on both blade and tongue. Fig. 11 illustrates a method in which no other tools are needed. A line is squared across a board having a straight edge. Equal distances are measured from the point at which the line cuts the edge, the blade then being made to pass through these points while the beam is held tightly against the edge.

For angles of 30 degrees and 60 degrees, square a knife line at right angles to an edge. Fig. 12. Measure from the edge, along this line, or from this line along the edge any given distance. Take twice this distance upon the blade of the bevel and adjust so that a right triangle is formed in which the length of the longest side shall be twice that of the shortest.

The graduations on the beam are seldom reliable. It is safer to set the gage with the rule by measuring the distance from the spur to the gage block. This is done by holding the gage bottom side up in the left hand. With the right place the end of the rule against the head. Fig. 13. After the screw has been tightened, apply the rule again to make sure of the correctness of the setting.

To gage the line, take the tool in the right hand, three fingers grasping the beam, first encircling the head for narrow work, and the thumb back, or nearly back, of the spur. Fig. 14. The head should be kept against one or the other of the face sides. Begin at the end of the piece which is towards you, hold the block firmly against the piece, roll the beam forward until the spur barely touches the surface and make a very light line. Fig. 15 illustrates the manner of raising the spur from the wood by raising the wrist during the backward stroke. It will be found convenient to hold the piece against the bench stop. This steadies the piece and permits the worker to see how deep the spur is cutting and whether the head is against the face properly. Avoid deep lines. They are inaccurate even if straight and always cause trouble in the making unless the grain of the wood is perfectly straight.

Fig. 17 illustrates a method frequently used by carpenters. The fingers act as a gage head.

In laying out rough stock, if the first edge is sufficiently straight, it is usual to thumb-gage for width. This is done by holding the pencil at the end of the rule and using the thumb of the left hand as the gage head, drawing the whole towards you with the rule acting as gage-beam. Fig. 22.

A straight-edge, a board with a straight edge, is often used in marking out. Mark off the length of the piece of wood required. Mark off the breadth at the end of the board, also mark it near what is to be the other end of the piece. Place the straight-edge on these two marks and draw the line. Fig. 23. The try-square should be used to mark across the grain.

SAWS.

To prevent the sides of a cut or kerf from binding the saw, the teeth are bent alternately from side to side, that the opening may be wider than the blade is thick. The saw teeth are then said to have "set." To do good work, a saw should have no more set than is necessary to allow a free movement. Fig. 25. Damp, spongy lumber will require considerable set, while well seasoned lumber necessitates but little.

The rake, or pitch of the teeth of a saw is the degree of slant which the cutting edges possess with reference to an imaginary line passing thru the points of the teeth. Fig. 25. The amount of pitch given will depend upon the use to which the saw is to be put, whether for ripping or cross cutting, and somewhat upon the hardness or softness of the wood to be cut. Fig. 26 shows the saw in proper position. It should be held in the right hand with the left hand grasping the board, the thumb of the left hand acting as a guide in the beginning. The thumb should be held firmly on the board and the blade of the saw should be pressed lightly against it. The cutting edge of the saw should be held at an angle of about forty-five degrees to the board and should be started on a backward stroke. The first few strokes should be short ones, increasing gradually in length.

If the tool is sharp, but little pressure will ever be required and, in starting, the tool must be held up so that its weight shall come upon the wood gradually. Saws can be guided better if the index finger of the right hand is allowed to extend along the side of the handle. Test occasionally, sighting down the saw blade to see that the sides of the saw are at right angles to the surface of the board. A try-square may be used by the beginner, as shown in Fig. 26.

If the saw does not follow the direction of the line, the blade should be slightly twisted, as the sawing proceeds, in the direction it ought to take. This must be carefully done so as not to cause the blade to bind and kink. In sawing a board which has been fastened in the vise, the most convenient position is obtained by sawing at right angles to the surface. Unless the saw has considerable set, difficulty will be experienced in changing the direction of the cutting should this be necessary. This may be overcome by lowering the handle so that the cutting edge shall make the same angle with the board as when the board rests on trestles.

When making a long cut, should the kerf bind, a wedge may be inserted as shown in Fig. 26.

All saws will work easier and will be found less likely to rust if their sides are rubbed occasionally with an oily rag or a piece of tallow.

The pitch given the teeth of a crosscut saw will vary with the hardness or softness of the wood which is to be cut. For all-around use the amount of slant is about one-third of the whole tooth. Fig. 27.

In using this saw, Fig. 31, hold the work firmly against the stop of the benchhook with the left hand, guiding the saw with the forefinger or thumb placed against the blade just above the teeth. Begin on the backward stroke, holding the handle end of the saw highest. Begin at the farthest corner, using short, easy strokes. Gradually lower the handle to a horizontal position, meanwhile increasing the number of teeth used, but continuing the slow, regular strokes.

In accurate cutting, Fig. 32, where no paring or block-planing is to be done, the saw teeth should cut just by the line, with the kerf in the waste, but with no wood between the line and the kerf. To allow for paring or block-planing, saw about one-sixteenth of an inch in the waste. Fig. 33.

When ripping, place the piece in the vise and begin sawing as indicated in Fig. 34. Place the saw so that just the whole of its thickness is in what is to become waste wood. Begin sawing as was done in crosscutting. Gradually lower the handle, while sawing, until most is being cut from the side nearest you. Fig. 35. Reverse the wood several times, working down one side then the other until the cross lines are reached. Fig. 36 illustrates the result of good and bad sawing.

This saw may be used for cutting enclosed curves by boring a hole, releasing one end of the blade and inserting it thru this hole then replacing it in the saw frame.

As the cut of the turning saw is not very smooth, it is advisable to leave about one-sixteenth of an inch between the kerf and the line, to be removed later with the spokeshave.

The teeth are first set. Fig. 39 shows a common form of saw-set in position. Beginning at one end of the saw, every other tooth is bent outward by means of this instrument. The saw is then reversed and the remaining teeth are similarly treated.

As these saw-sets are adjustable, the teeth may be bent much or little as the work to be done demands.

Second, the teeth are jointed. A flat file is run lengthwise over them the full length of the saw so that none of the teeth may project more than others. Fig. 40 shows a flat file in position for jointing. This block keeps the surface of the file at right angles to the blade of the saw.

Third, the saws are filed, a three-cornered file being used for this purpose. The kind of saw determines the angle or angles at which the file is held with reference to the saw blade. Fig. 41 illustrates the position when filing the crosscut and Fig. 42 the rip-saw.

Fourth, the teeth are side jointed by laying the saw flat upon the bench and rubbing an oil-stone over each side lightly, once. Fig. 43. This is to even the sides of the teeth that the kerf may be smoothly cut.

PLANES.

The two irons of the plane, the plane-iron or plane-bit, and the cap-iron are fastened together by means of a stout screw. Fig. 46.

This cap-iron serves a double purpose. First: It stiffens the plane iron; second, it serves to bend and break the shaving and thereby prevent a splitting action in front of the cutting edge. This action would surely occur were the grain in the least unfavorable and the cap-iron not used. Fig. 47.

The cap-iron and plane-iron are fastened in the throat of the plane by a cap on one end of which is a little lever or cam.

Should this cam fail to hold the irons firmly, the screw which holds the cap to the frog should be turned with the screwdriver. It should be remembered, however, that this screw, once set, seldom needs adjusting.

Beginners frequently, in ignorance, place the plane-iron and cap-iron together so that the side of the plane-iron having the bevel is next the cap-iron. This results in a loose acting cam and they should look to see that the irons are properly set before changing the screw.

Should it be impossible to force the cam into place without great pressure, first look to see whether the blade rests flat upon the frog before releasing the screw. Frequently the little lever which should enter the small opening in the cap-iron will be found to have entered the opening in the plane-iron only.

A little observation of the action of the screw upon the lever which connects it to the plane iron will show that there is often quite a little lost motion so that it becomes necessary to turn the screw a little before the iron is raised or lowered any. One soon learns by the sense of feeling when the lost motion has been taken up.

The second adjustment is by means of the lever, 9, Fig. 46. Moving this lever to the right or the left serves to straighten the plane-iron, so that the cutting edge shall extend evenly through the mouth and not take a shaving thicker at one side of the iron than at the other.

In adjusting a plane-iron, turn the plane upside down with the toe towards you, hold it toward the light and sight along the bottom, Fig. 49. If the plane-iron projects, observe whether it projects evenly or not. Usually one side will be found to project more than the other. Move the adjusting lever until it shall project uniformly. The cutting edge should project about the thickness of a piece of drawing paper for average work.

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