Farm Woodwork And Carpentry

CHAPTER'!

MEASURING AND MARKING

Although there is an increase in the amount, of steel and other metals used in farm machinerjr and equipment, there will always be a need for the farmer to make repairs and construct appliances involving the use of wood. It is a simple matter to become reasonably proficient in the use of woodworking tools, bccause woodworking, like most other kinds of mechanical work, is based upon a comparatively few fundamental tool processes or operations, like sawing and planing. Once these are mastered, one is well on his way toward becoming a proficient woodworker.

1. Measuring with the Rule.—Accurate measuring and marking is the first, requirement for good work in the shop. In making accurate raeas-

Fig. 1.—Accurate measurement« can best be made with a rule laid on edge. When making several measurements in a straight- line, do not raise the rule until all are marked.

urements with a rule, the measurer should lay the rule on edge so that the graduations touch the work being marked.

In making several measurements in a straight line, it is best to mark off all measurements without raising the rule, for if the rule is raised and each measurement made separately, then there is much more possibility of errors.

Fig. 1.—Accurate measurement« can best be made with a rule laid on edge. When making several measurements in a straight- line, do not raise the rule until all are marked.

An easy method of locating the middle of a board is to place the rule across the board at an angle so that major divisions, as even inch marks, coincide with the edges of the board. The middle of the board is then midway between these two major divisions of the rule. A similar method may be used for dividing a board into several equal widths.

In reading a fractional measurement on a rule, it is best to think of the measurement as a major fraction plus or minus a small fraction. For example, in. is % in. minus in. is yi in. plus etc.

2. The carpenter's steel square is also used for measuring and dividing distances. In addition, it is used for marking off lines at right angles to an edge of a board or to another line, and for laying out other angles (see Art. 17, page 12).

Fig. 2.—A. An oaey method of marking tho middle of a board. The rule is laid across the board at an angle with two oven inch marks coinciding with the edge«, and then the mid-point. is marked.

B. In a similar manner, a hoard is easily divided into a number of »qual widths.

Fig. 2.—A. An oaey method of marking tho middle of a board. The rule is laid across the board at an angle with two oven inch marks coinciding with the edge«, and then the mid-point. is marked.

B. In a similar manner, a hoard is easily divided into a number of »qual widths.

3. The try square is used mostly at the workbench for (1) measuring short distances, (2) laying out lines perixmdicular to an edge or side of a board, (3) checking edges and ends of boards to see if they are square with adjoining surfaces, and (4) checking the width or thickness of narrow boards. In order to keep the try square accurate, care should be taken not to drop it. The try square should never be used for hammering or prying.

In squaring with a try square, the handle should always be held firmly against either the working surface or the working edge of the board. (Bee Art. 37, page 30, for definitions of working surface and working edge.)

4. Testing a Square.—If a square is suspected of not being true, it may be tested easily. Use a board that has a perfectly straight edge. Place the blade of the square along the straight edge and mark a line across the board (presumably at right angles to the edge). Turn the square around (Fig. 5) and see if the line still checks square. If not, the square is not true.

If a steel square is found not true, it may be adjusted by placing the corner of the square flat on an anvil and hammering carefully to stretch the outer part or the inner part of the corner, as may be required.

5. The bevel is used for laying out and checking angles and bevels. The blade is adjustable and is held in place by a thumbscrew. After it is

A. Marking off short measurements.

B. Cheeking an edge for squareness with a surface.

C. Checking an end for squareness with an edge.

D. Squaring across a surface.

E. Squaring aoroas an edge.

stretch the outer part or the inner part of the corner, as may be required.

5. The bevel is used for laying out and checking angles and bevels. The blade is adjustable and is held in place by a thumbscrew. After it is

A. Marking off short measurements.

B. Cheeking an edge for squareness with a surface.

C. Checking an end for squareness with an edge.

D. Squaring across a surface.

E. Squaring aoroas an edge.

set to the desired angle it is used in a manner similar to the try square. For setting the bevel at angles of 30,45, or 60 deg., the methods illustrated in Fig. 7 may be used.

6. Marking with a pencil or knife should be done carefully. The square or rule should first be very carefully placed, and then a sharp pencil or knife should be drawn along the straight edge of the rule or square so as

against the edgo and mark close to the tongue of the square.

r i i 1

^——j- ■

________

L____________

1 l'i! ill 1 il .1.1. i.i, l.l.l

Fig. 5.—To teat a square, square a line acrosa a board that has a straight edge. Then turn the square over and ?ee if the line chock* square.

Fig. 5.—To teat a square, square a line acrosa a board that has a straight edge. Then turn the square over and ?ee if the line chock* square.

to make a line narrow line very close to the edge. A knife makes a finer line than a pencil and is recommended for very accurate work. For most farm shopwork, however, a sharp-pointed pencil is accurate enough. A hard pencil stays sharp longer and makes a finer mark than a soft one.

7. The marking gage is used to mark lines parallel to the sides, edges, or ends of a board. The spur in the gage should be filed to a sharp point so as to make a very fine line, and it should be set to protrude through the

Fig. 7.—Methods for sotting the bevel at common angles. A, 45 deg.; B, GO deg.; C,

30 deg.

beam about % in. After setting the gage it is best to check the setting with a rule. In using the gage, the head should be held firmly against the surface from which the line is being gaged, normally against the working surface or the working edge. Also the gage should be rolled forward slightly to allow the spur to drag at a slight angle \ / ^ ;V

and thus prevent gouging (see Fig. 10). M I V ' ' \ 1

8. Gaging with a Pencil.—Gaging may be done with an ordinary rule and a pencil. The rule is grasped in one hand i^^^^j^^Y^Sl with the thumbnail firmly placed against the edge of the rule and at the desired ftg. s.—For »count« work, distance from the end. The rule is then marking with a knife is better than drawn along with the thumbnail against apo,i'" the edge of the board and with a pencil held in the other hand at the end of the rule (see Fig. ll^i).

For gaging narrow widths where extreme accuracy is not required, a pencil may be held between the thumb and first two fingers and drawn

Fig. 7.—Methods for sotting the bevel at common angles. A, 45 deg.; B, GO deg.; C,

30 deg.

along the edge of the board with the second, third, and fourth fingers against, the edge of the board (see Fig. MB).

Another simple method of pencil gaging is illustrated in Fig. 11C. The pencil is grasped in the closed fist with the point protruding out the

Fio. 9.—The setting of the marking gage ahould be checked with a rule.

distance the line is to be marked from the edge. The pencil is then drawn along with the thumb and first finger firmly against the edge.

9. Dividers are used for (1) marking out circles and part circles, (2) transferring or duplicating short, measurements, and (3) dividing distances

Fro. 10.—In using the marking gage. hold the head firmly against- the edge of the board and roll the beam slightly forward so that the spur drags at a slight angle.

Fro. 10.—In using the marking gage. hold the head firmly against- the edge of the board and roll the beam slightly forward so that the spur drags at a slight angle.

into a number of equal parts. In setting a pair of dividers, the thumbscrew is loosened until the legs are approximately set, and then it is tightened. A fine or close adjustment is then made with the thumb nut at the end of the arc (see Fig. 12).

To divide a line into a number of equal parts, say three, the dividers are set by guess to one-third the total length. The setting is then checked by stepping off three steps and seeing if the three steps equal the total length. If the setting is too large, then the dividers are set closer, by guess, by one-third (why one-third?) the distance overstepped on the last step. (If the setting is too small, the dividers are set wider.) The new setting is then checked by stepping off the line again.

10. Laying Out Duplicate Parts; Superposition.—In marking out two or more pieces that are to be alike in all or part of their dimensions, much time may be saved and more accurate work insured by marking all pieces at the same time, or from a pattern.

Frequently in shopwork a piece can be marked for the required sawing, cutting, or boring by superposition—that is, by properly placing the parts together and marking them.

In marking out a number of pieces that are to be alike, rafters for example, the same piece should always be used as the pattern to insure uniformity.

Thumb screw for coarse adjustment

Fi q. 12.—To set a pair of divider», make an approximate adjust men t with the thumbscrew and then make the fine adjustment with the nut at the end of the arc. Steadying the knuckle against the bench top helps to hold the points accurately.

Fig- 13.—One leg of the dividers may be accurately placed by holding it between the thumb and finger and steadying the hand against the bench top.

Fig. 14-—Forethought and planning in laying out and marking duplicate part« save* time and help« to insure accuracy.

A. Marking duplicate parts at the aame time.

B. Marking duplies parts with a pattern. (Alwaya use the same piccc for tho pattern).

C. Marking the width of a notch by auperporition.

Fig. 14-—Forethought and planning in laying out and marking duplicate part« save* time and help« to insure accuracy.

A. Marking duplicate parts at the aame time.

B. Marking duplies parts with a pattern. (Alwaya use the same piccc for tho pattern).

C. Marking the width of a notch by auperporition.

LAYING OFF LINES IN BUILDING CONSTRUCTION

11. Making a Chalk Line.—A quick and simple method of marking off a straight line on a floor, wall, ceiling, or piece of lumber is to use a chalk line, that is, a string or cord that has been rubbed with chalk and coated with chalk dust. The line is stretched tightly between the two points on the surface that are to be joined by a straight line and held in place by a helper or fastened, as by wrapping or tying around nails. The line is then raised off the surface at a point between the two ends and allowed to snap back into place. A straight chalked line is the result.

12. Laying Off Long Lines at Right Angles.—A method, known as the 6-8-10 method, is very good for laying off long lines at right angles to each other, as in laying out the sides of a foundation for a building. The carpenter's square is too small for accuracy on such work. This method and from the other end an arc with a radius of 10 ft. A line from the point of intersection of these arcs to the center of the 8-foot arc, that is, to that end of the 6-ft. line from which the 8-ft. are was swung, will be perpendicular to the first line.

13. Laying Off a Line Parallel to Another.—One method of laying off a line parallel to another is to erect a perpendicular to the first line and measure out on it a distance equal to the distance the two parallel lines are to be separated. At this point on the perpendicular erect a second perpendicular, using the 6-8-10 method. The third line will then be parallel to the first.

Another method is to erect perpendiculars to the first line at two widely separated points on the line. Measure out on each perpendicular the same distance. A line passed through these two points will be parallel to the first line.

Fig. 16.—The 6-8-10 method of laying off lines at right angle«.

Fig. 16.—The 6-8-10 method of laying off lines at right angle«.

is based upon the fact that, if one side of a triangle is 6 ft. long, the second side 8 ft. long, and the third side 10 ft. long, then the triangle is a right triangle. Instead of 6, 8, and 10 ft., multiples or sub-multiples of these figures, as 30, 40, and 50, or 3, 4, and 5, may be used. The larger the numbers, the more accurate the work is likely to be. A practical way of using this method is to measure a distance of 6 ft. along one line (see Fig. 16). From one end of this 6-ft. line swing an arc with a radius of 8 ft.,

14. Use of the Plumb Bob.—The easiest method of locating a point directly beneath another Is to suspend a plumb bob from the first point, being careful to allow the bob to come to rest before marking beneath it, and being careful not to let the wind blow it. In case a plumb bob is not available, a symmetrical weight like a nut may be carefully suspended from a string and used for rough work.

Figure 18 illustrates a method of establishing a level line by means of a plumb bob and square.

Plumb Bob Divide Image
Fio. 17.—Using the plumb bob.

15. The Level.—The level is used to indicate when a surface is horizontal. The bubble vial or tube has a very gentle curvature and is almost filled with a nonfreezing liquid. The tube is mounted so that when the base of the level is horizontal, the bubble will be in the middle.

Levels are commonly equipped with a second bubble tube located near one end. This second tube is mounted perpendicular to the base of the level, and is used in checking vertical pieces for plumb.

16. Testing a Level for Accuracy.—To test a level, place it on a bench or some other convenient surface, and wedge up under one end until the bubble comes to center. Then turn the level end for end. The bubble should return to center; if it does not, the level is not in adjustment. Mast good levels can be adjusted by turning a screw in the bubble-tube mounting.

17. Laying Off Angles with the Square.—The carpenter's steel square is commonly used for marking off angles in carpentry and in measuring

Fig. IS.—Establishing a level line by means of a plumb bob and square.

angles and describing them so they may be duplicated. Suppose that the end of a board is cut off at an angle and it is desired to cut another board just like it. The square is placed with the tongue along the end of the board (see Fig. 20) and then the readings are noted where both the body

Fig. 19.—Testing a level for accuracy. The bubble should return to oent^r when the level is turned end for end on a level surface.

of the square and the tongue touch the edge of the board. If the square is placed on the second board with these same two readings along one edge of the board, a mark along the tongue will give exactly the same angle as on the first board.

Fig. IS.—Establishing a level line by means of a plumb bob and square.

angles and describing them so they may be duplicated. Suppose that the end of a board is cut off at an angle and it is desired to cut another board just like it. The square is placed with the tongue along the end of the board (see Fig. 20) and then the readings are noted where both the body

Fig. 19.—Testing a level for accuracy. The bubble should return to oent^r when the level is turned end for end on a level surface.

The readings on the square should be taken as large as convenient in order to insure accuracy. For instance, a setting of 1.2 and 4 would be preferable to 6 and 2 or 3 and 1.

18. Measuring the Width of Openings.—A convenient method of measuring the -width of a door opening, or similar opening, is to extend two yardsticks or pieces of scrap lumber until they span the opening. The measurement may then be transferred to a single board or picce and the exact measurement determined in feet and inches if desired.

19. Board Measure.—Lumber is sold by the board foot, or foot, board ■measure, which is the amount of lumber in a piece 1 in. thick, 1 ft. wide, and 1 ft. long. Since a foot, board measure, is one-twelfth of a cubic foot, the number of feet, board measure, in one or more pieces of lumber may be determined by first finding the cubic feet contained in the piece or pieces and multiplying by twelve. This method at 6rst may seem to be very tedious, but in practice it is a very simple and easy one. To use it, simply apply the following simplified formula:

Feet, board measure =

number of pieces X inches thick X i nches wide X feet Ion g

For example, to find the feet, board measure, in three two by fours, 10 ft. long:

it . u a « X 2 X 4 X 10 OA Feet, board measure = --—j^---— 20

Cancellation will nearly always simplify the figuring so that it may be done without tedious multiplication and division.

Lumber that is less than 1 in. thick Is commonly figured in square feet instead of board feet.

Mill-surfaced lumber is never full width nor full thickness, owing to waste removed when the boards are surfaced or planed. In figuring the board measure, however, it is always figured as if it were full width and thickness. For example, a two by four actually measures only about by in. but is always figured as full 2 by 4 in.

When ordering or buying lumber to cover a given surface, the area of the surface is first determined, which will be theoretically the number of board feet of lumber required, assuming that the lumber is 1 in. thick. In practice, however, it is always necessary to add a certain amount to this figure, the amount depending upon how much the board lacks of covering its nominal width. About one-twelfth will need to be added when one by twelve sheathing or barn boards are used; about one-tenth for one by tens; and about one-eighth for one by eights. For tongue-and-grooved or matched lumber like shiplap, flooring, siding, and ceiling, an amount varying from one-eighth to one-third or more must be added, depending upon the width of the boards and the amount of lapping in the grooves.

Questious

1. (a) Why should the rule be laid on edge when making measurements? (b) In makiug several measurements in a straight lino, why should all measurements be marked without raising the rule? (c) Describe an easy method of locating the middle of a board, (d) How may a board be divided into several equal widths? («) How can such measurements as be easily located on the rule?

2. Give three or four uses of the carpenter's steel square.

3. (a) Give four uses of (he* try square, (&) How should (he try square be held in squaring lines on a board?

4. (a) How may a square be tested? (6) How may a steel square be adjusted if not, true?

6. (a) What is the bevel and for what work is it used? (6) How may a bevel be set for angles of 30, 4o. and 00 dcg.?

6. (a) What precautions should be used in marking with a pencil or knife? (b) For what kind of work is marking with a knife preferred to marking with a pencil?

7. (a) For what is the marking gage used? (6) How far should the spur protrude through the beam? (c) How may the setting of a marking gage be checked? {d) What precautions should be observed to prevent gouging and to insure good work with the marking gage?

8. Describe and be able to demonstrate two methods of pencil gaging.

9. (a) Give three uses for dividers. (6) How arc dividers set? (c) How may the dividers be used to divide a line into a number of equal parts?

10. Describe two good methods of marking duplicate parts.

11. Explain how to make a straight line by using a chalk line.

12. (a) Explain how a right angle may be laid off with the G-8-10 method. (&) In what respects is this method superior to using a carpenter's square?

13. Describe two methods of laying off parallel lines.

14. For what is the plumb bob used?

16. (a) How is a level constructed so that it can be used to indicate when a surface is level? (6) Why do some levels have more than one bubble tube?

16. How may a level be tested for accuracy?

17. (a) Explain how the steel square may be used to lay off. or to duplicate, angles. (b) Why is it better to use large readings than small ones on the square when laying off angles?

18- Explain an easy way of measuring the exact width of an opening like a door opening.

19. (a) What is a foot, board measure? (b) State a rule for figuring the board measure of a piece of lumber and give an example of its use. (c) When is lumber figured in square feet instead of feet, board meaaure? (<d) Why will 100 ft.b.m. of lumber not cover a full 100 sq, it. of surface?

References

Kjorth: "Basic Woodworking Processes."

Brown and Ttjstison: "Instructional Units in Hand Woodwork."

Griffith: " Essentials of Woodworking/'

JJoss, Dent, and White: "Mechanical Training/'

Educational charts and pamphlets, Stanley Tool Works, New Britain, Conn.

CHAPTER IT

Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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Responses

  • chiara
    How far should the spur protrude through the beam?
    2 years ago

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