Rural Building; Basic Carpentry

By: J. van Winden

CONTENTS

TECHNICAL TERMS

TESTING BOARDS

Winding strips / How to test small work pieces / How to test long work pieces

MEASURING AND MARKING OUT TIMBER

Measuring with a rule / Marking out with a rule / Marking with a pencil / Marking with a chalk line

TIMBER CONSTRUCTIONS

PREPARATION OF TIMBER

Sequence of operations for preparing timber / Timber marks / Marking of frames / Cutting list

FASTENING WITH NAILS

Driving nails / Holding power / How to prevent splitting during nailing / Finishing off

FASTENING WITH SCREWS

Holding power / Driving screws in soft wood / Driving screws in hard wood

ANGLE JOINTS

Nailed butt joint / Plain mitred joint / Rebated butt joint / Sequence of operations for constructing a box with this joint / Housed joint / Sequence of operations for constructing the joint / Common mortice and tenon joint for box-like constructions / Sequence of operations for constructing the joint / Cornerlocked joint / Sequence of operations for constructing the joint

FRAMING JOINTS

Halved joints / Sequence of operations for constructing the joint / Corner-halved joint / Cross-halved joint / Stopped tee-halved joint / Common mortice and tenon joint for frame-like constructions / Sequence of operations for constructing the joint / Haunched mortice and tenon joint / Stub tenon joint / Twin tenon joint / Securing the joints / Bridle joint / Sequence of operations for constructing the joint / Corner bridle joint

WIDENING JOINTS

Plain glued butt joint / Dowelled widening joint / Rebated joint / How to plane a rebate with an ordinary rebate plane / How to plane a rebate with an adjustable rebate plane / Loose tongued joint / How to plane a groove for a loose tongued joint

MISCELLANEOUS CARPENTRY TECHNIQUES

Marking a board to fit an irregular surface / Measuring the width of openings / Marking out irregular designs with templates

BASIC CARPENTRY TECHNIQUES

TECHNICAL TERMS.

GRAIN: This refers to the direction of the wood fibres. Length is measured along the direction of tte grain. Width is measured across the grain at right angles to the length. When wood is cut across the grain, END GRAIN is exposed.

WITH THE GRAIN: This term is used in connection with planing. If the fibres are cut cleanly and smoothed down by the cutting iron, the wood is said to be planed with the grain; like stroking a dog's coat so the hair lies down smoothly.

AGAINST THE GRAIN: Tills means that the plane goes in the opposite direction, lifting and breaking the wood fibres and leaving a rough surface; as If a dog's coat were brushed the wrong way and roughened.

STRAIGHT GRAIN: The wood fibres lie straight and parallel to the length of the piece of wood. Such wood planes smoothly and easily.

CROSS GRAIN: The wood fibres do not lie parallel to the length of the piece. This mates the wood hard to work,

BEVEL: This is made by planing off the sharp edge to form a new surface which is not at right angles to the side of the piece of wood. A CHAMFER is a special bevel, cut at 45 degrees. A "through" chamfer or bevel runs the whole length of the edge (Fig. 1). A "stopped" chamfer or bevel is stopped at one or both ends (Fig. 2).

GROOVE: This is a recess cut along the grain. A "through" groove runs the whole length or. the piece (Fig. 3, a); while a "3topped" groove is stopped at one or both endu (Fig. 3, b).

TRENCH: This is a recess cut along the grain. A trench can also be either through (Fig. 4, a) or stopped (Fig. 4, b).

REBATE: This is a recess cut along the edge or across the end of a board as in Figs. 5 & 6.

TRUE: in woodworking this indicates that a surface is flat and perfectly level.

SQUARE: Square angles are exact 90 degree angles. "Square" is used to describe pieces in which all the corners and edges have 90 degree angles.

SHOULDER: The vertical portion of a trench or rebate (arrows, Figs. 5 & 6).

TESTING BOARDS

When you prepare a board for use in some project, you must make certain tests on it to make sure that it is flat and true in all directions and that the angles and corners are all square. These tests are made during the actual preparation of the timber, but we describe them here separately because they are generally useful techniques which you will need again and again in your work.

Before you continue reading, look in your Rural Building Reference Book, Tools section, and read about the try square, which is one of the tools you will need for testing boards. You will also need winding strips (Fig. 2) and a straight edge (Fig. 1), which is usually a piece of wood with one long edge that you are sure is perfectly flat and straight.

Also look in the Reference Book, Materials section, and find out what is meant by the words: twisting; cupping; and bowing.

WENDING STRIPS

These are used as an aid to help you to see ii a board twists or "winds". They are two strips of wood about 35 cm long, 2, 5 cm wide and 1,5 cm thick. The top edge has a bevel and all the edges must be perfectly straight. One of the two strips may be made darker so that sighting along them is easier (Fig. 2).

HOW TO TEST SMALL WORK PIECES

Test with the try square or the edge of a jack plane in different positions for flathess. Also test the squareness of the edges with a try square at a few different spots (Fig. 3).

HOW TO TEST LONG WORK PIECES

Test for winding (twisting) using the winding strips; one at each end of the board, across the grain. Go to the end of the board and look along the board, with your eye just at the same level as the strips (Fig. 1), When the top edges of the strips do not appear parallel (Fig. la), the board is not flat. Check with the winding strips at different spots, making sure that the strips are parallel (Fig. lb).

Test for cupping by putting a try square across the grain at different spots along the board. If you check this against the light, you will see all of the uneven places (Fig. 2).

To check for bowing you can do the same test, using a straight edge along the grain (Fig. 3).

For long boards you can sight along the boards with one eye closed, to see the places which are uneven (Fig. 3a).

Using a try square, check whether the angle between the face side and the edge is exactly 90 degrees. Make this test at several places (Fig. 4).

When all these tests have been performed with satisfactory results, the board will be straight and true in all directions and it is ready to be used in a project.

MEASURING AND MARKING OUT TIMBER

Accurate measuring and marking out are the first requirements for success in the building trade. Common measuring and marking tools are the folding rule and zig-zag rule.

MEASURING WITH A RULE

To measure between two points, place the role on one point and read the mark nearest to the other point (Fig. 1).

When the end of the rule has become worn and inexact, you can still get an exact measurement. Place the 1 cm mark of the ruler at the first point and read at the second point. The true measurement is that reading minus 1 cm. For example, the measurement in Fig. 2 is: 3.5 cm minus 1 cm equals 2.5 cm.

MARKING OUT WITH A RULE

To mark out measurements with a rule, place the end of the rule (or the 1 cm mark) carefully at the start of the measurement and then make a fine mark with a pencil exactly even with the marking on the rule at the correct distance.

For very accurate marking and measuring, lay the rule on its edge so that the marks on the rule touch the work (Fig. 3).

To mark out several measurements on a line, it is best to mark all of the measurements without raising the rule or moving it. If the rule is moved and each measurement is made separately, there is a much greater possibility of error.

MARKING WITH A PENCIL

When a marking gauge is not available, straight lines can be gauged along timber by one of the following methods.

Grasp the pencil lightly in your closed fist with the point protruding the desired distance. For example, to make a line 1 cm from the edge of the timber, the point of the pencil should stick out exactly 1 cm from your fist. Now pull the pencil along the board keeping your thumbnail pressed firmly to the edge of the board (Fig. 1).

To gauge lines further from the edge of the board, use a rule and a pencil. Grasp the rule in one hand with your thumbnail at the desired marking. Then draw the rule along while keeping your thumbnail against the edge of the board. With your other hand hold a pencil at the end of the rule to make the line (Fig. 2).

With these methods you should be careful not to get splinters in your fingers.

Another method of drawing lines parallel to an edge is with a small pencil gauge. This is simply a small, rebated wooden block which is pressed against the edge of the timber and used to guide the pencil, as shown in Fig. 3. The pencil gauge is often used to mark out the position of chamfers.

A straight edge can also be used in marking out longer lines. MARKING WITH A CHALK LINE

A quick and simple way of marking out a straight line on any surface is with a chalk line. This is simply a piece of string that has been rubbed with chalk until it is coated in chalk dust (charcoal may also be used for this purpose).

To use the chalk line, stretch the line between two points which are the ends of the line you want to mark. Hold it in place by tying the ends to nails, or have a helper hold it for you.

Lift the line up in the middle and allow it to snap back (Fig. 4), making a straight chalk line on the surface.

TIMBER CONSTRUCTIONS

The last few lessons were about the very basic things you will need to know before you can actually make any construction of wood. Therefore we started with some technical terms which are important because you will see them again and again in the lessons and will use them in practical work.

The next sections include all the information you will need to prepare for a project: how to get the wood pieces to the right size and shape; how to mark the timber; and how to plan a project using a cutting list. included here is a section on nailing and one on driving screws. Before you study those sections, look up nails and screws in the Reference Book, so that you are familiar with the parts of nails and screws and how they look.

Each section starts with a list of tools. Refer to the Reference Tools section, and learn about each of these tools before you study the rest of the section.

PREPARATION OF TIMBER

In order to carry out the construction of any practical exercise or project, it is essential to have the wood pieces for the project prepared so that they have the correct size, true and flat surfaces, and square corners and angles.

There is of course a correct procedure to be followed for this preparation. It is important to carry out the following steps in their correct order on every piece of timber, whether large or small.

An easy way to remember the steps in their correct order is to keep the following word in mind: FEWTEL.

Face	Edge	Width	Thickness	End	Length
F	E	W	T	E	L

The tools which are required for this preparation are the bench, jack plane, straightedge, winding strips, pencil, try square, marking gauge, charcoal line, back saw, ruler and crosscut saw. Look these up in the Reference Book and make sure that you understand what they are and how they are used.

SEQUENCE OF OPERATIONS FOR PREPARING TIMBER

Step 1. Plane the face side (F)

Put your work on the bench with the better side up. If the board is not flat, put the hollow side down to keep it from rocking or moving around. in the case of very long or thin boards or twisted or deformed boards, put thin wedges of wood underneath where needed, to keep the work steady and keep it from bending in the middle during planing.

Plane this side perfectly true.

Test for flathess with the straight edge, winding strips and try square.

Mark this side as the face side; the face mark should point to the edge which will be the face edge. The face edge will be the best edge of the board.

Step 2. Plane the face edge (E)

Fasten your board to the side of the bench, with the face mark up. The planed side must be towards you and not against the bench, unless this would mean

you would have to plane against the grain. in that case, you should turn the board so the other edge is up, keeping the face side towards you because the try square has to be set against the face side.

Plane the face edge perfectly straight and square to the face side.

Test for straighthess with the straight edge and for squareness with the try square.

Mark it with a face edge mark pointing to the face side.

Step 3. Plane the width (W)

With a marking gauge, mark the width of the board. Press the gauge against the face edge and mark on the face side.

Plane down to the middle of the gauge line and be careful to get a square, straight edge when you reach the mark.

Test for flathess with a straight edge and try square.

NOTES:

During planing mind the direction of the thread of the wood.

Step 4. Plane the thickness (T)

Use a marking gauge to mark the thickness of your board. Press the gauge against the planed side and mark both edges.

Plane down to the middle of the gauge lines.

Test for flathess as you get near the two marked lines. Be sure to check for flathess across the board at several points. Check for winding with the winding strips.

Generally timber is not prepared to the exact length. Waste is left on each end to protect the corners from damage. If it is necessary to prepare it to the exact length, the procedure is as follows:

Step 5. Cut one end (E)

With a try square, square the best end; with as little waste as possible.

Cut that end perfectly square to the face side and face edge. Saw on the waste side of the line.

Test for squareness in all directions.

Mark the end with a cross, so that you know whijh is the prepared and tested end.

Step 6. Cut the length (L)

Measure the required length from the prepared end and square with the try square.

Cut that end perfectly square in all directions.

Test it with a try square.

TIMBER MARKS

The purpose of face marks, as they are shown under preparation of timber, is to show clearly the prepared and tested sides and the adges which are square.

During all further marking, squaring and gauging we should try to work from these sides and edges.

MARKING OF FRAMES

Making frames is an important part of Rural Building. We have to mark the members of a frame in a standard way so that we do not confuse their positions.

Select and prepare the timber according to the sequence given in the section on preparation of timber. Lay out the various members as they will be when they are finally assembled into a frame (Fig. 1).

Take care that all surfaces which will be visible in the finished product are of good timber and without defects. Usually these will be the face sides and face edges. Always try to keep the face sides on one side, and the face edges all on the inside or all on the outside.

Now put the inside edges of the horizontal members together, mark the length of the members and put the triangular mark as shown in Fig. 2. The triangle always should point up.

New do the same thing for the vertical members. Put the inside edges together, mark the lengths and put the triangular sign, again pointing upwards (Fig. 3).

All further marking should be done using these sides as a reference.

CUTTING LIST

After you design and make the drawing for a piece of work, you need to make a cutting list showing the length, width and thickness of all the parts. These will be the finished sizes. So that each part will be straight, true and smooth, we must begin with slightly bigger pieces to have an allowance for planing the sawn timber true.

The planing allowance for a board is: 3 mm extra in thickness 6 mm extra in width 12 mm extra in length

For square pieces the allowance is: 3 mm extra on each aide 12 mm extra in length

An example is shown below of a cutting list for a simple box (Fig. 1). The list shows the parts of the box, the kind of wood, the number required of each part and the finished size of the part. in the last column we find the size of the timber that will be required when the planing allowance has been added.

Usually it is best to plan a project according to the sizes of timber you have available, subtracting the planing allowances first in order to prevent waste.

Cutting list:

			finished size (cm)			timber size (cm)
part	wood	no.	L	W	T	L	W	T
A	Odum	1	10,6	8	2,2	11,8	8,6	2,5
B	Odum	1	10,6	8	2,2	11,8	8,6	2,5
C	Odum	1	25	8	2.2	26,2	8,6	2.5
D	Odum	1	25	8	2,2	26,2	8,6	2,5

When you are choosing timber for a piece, choose the best, straight boards for the long pieces. The crooked or defective boards can be used for the shorter pieces.

FASTENING WITH NAILS

Before you read this section, look up Nails in the Reference Book, Products section, .

DRIVING NAILS

To start a nail, hold it steady between your thumb and fingers with one hand and strike one or two light blows with the hammer (Fig. 1).

After the nail is well started, drive it in with firm blows. Hold the handle of the hammer near the end and strike the nailhead straight.

When you drive a nail all the way in, be careful on the last blows not to hit the wood and leave a hammer mark on it.

HOLDING POWER

The holding power of the nail depends on the pressure of the wood fibres against the shank of the nail and also on the size of the nailhead (Fig. 2).

Hard dry wood holds better than soft or wet wood. End grain doesn't hold nails very well. If the nail is driven across the fibres, the nail's length should be 2| times the thickness of the top piece (Fig. 3). If it is driven into end grain, the length should be 3 times the thickness of the top piece (Fig. 4).

The holding power of nails in end grain can be improved by dovetail nailing, which means the nails are inserted at slight angles (Fig. 5) instead of straight in (Fig. 6) which is the usual way.

If possible the nails should be inserted at right angles to the force that will be applied to the piece; so that any force tends to shear off the nail rather than pull it out.

The correct placing of the nails is important with respect to the strength of the finished piece.

HOW TO PREVENT SPLITTING DURING NAILING

Nails can be staggered (inserted out of line) to prevent splitting along the fibres of the wood (Fig. 1).

Blunting the nail with, one or two hammer blows on the tip also helps to prevent the nail from splitting the wood (Fig. 2).

If large nails are to be fixed, drill holes first to keep them from splitting the timber. The holes should be slightly smaller in diameter than the nails.

FINISHING OFF

Lost head nails are punched (knocked below the surface of the wood) with a nail punch or a large blunt nail. The remaining hole can be filled with putty (Fig. 3).

When the sharp points of nails come all the way through the timber and out on the other side, they are clenched; that is the tips are bent over and flattened against the wood, out of the way There are two ways of doing this:

Knock the tip flat and punch It into the wood with a nail punch (Fig, 4).

Bend the point at a right angle first, and then knock It back into the wood (Fig. 5; a, b, & c). This is done where the nail projects more than 1 cm.

The head of the nail should be supported during clenching to keep it from being pushed out again.

Bent nails can be straightened If you tighten one end in a vice and support the other end with a hammer while knocking out the bent part with another hammer (Fig. 6).

FASTENING WITH SCREWS

Before you read this section, look up screws and screwdrivers in the Reference Book.

HOLDING POWER

The holding power of a screw depends on how the thread embeds in the fibres, the length of the screw and the strength of the head which holds the top piece.

When a screw is driven across the grain, the screw's length should be about twice the thickness of the top piece (Fig. 1).

Screws driven into the end grain should be longer, about 3 times the thickness of the top piece (Fig. 2).

DRIVING SCREWS IN SOFT WOOD

Bore a hole in the top piece with the same diameter as the shank of the screw (Fig. 3a). The bottom piece may be punched with a large nail or awl (Reference Book, page 73).

Countersink if necessary (Fig. 3b).

Drive the screw (Fig. 3c).

DRIVING SCREWS IN HARD WOOD

Bore a hole in the top piece with the same diameter as the shank of the screw (Fig. 4a).

Bore a hole in the bottom piece with the same diameter as the core of the screw (Fig. 4b).

Countersink if necessary and drive the screw (Figs. 4c & 4d).

Use a screwdriver with the correct tip only. If the screw turns too hard, the hole may be too smali or not deep enough. Remove the screw and find out what the problem is so it can be corrected, otherwise the screw may break or split the board.

Turn the screw down until the head is just seated. Overturning weakens the holding power and may break the screw.

To make driving easier and to protect against rust, a bit of soap or oil may be put on the tip of the screw.

ANGLE JOINTS

Angle joints are joints where the sides of the pieces (the wide surfaces) meet at right angles to each other. Angle joints are used for box-like constructions such as small boxes, tool boxes etc. For an example of a box using angle joints, see the illustration for the Cutting List lesson, on page 89. in this chapter we will consider the most common types of angle joints and their construction.

NAiLED BUTT JOINT

The simplest angle joint is the nailed butt joint. The end of one piece of wood is cut square, then butted against the face of the other piece. It is held in place with nails, or both nails and glue (Fig. 1).

PLAIN MITRED JOINT

The ends of the pieces are mitred (cut at 45 degrees) across the thickness. The mitred ends are butted together and held in place with glue and nails (Fig. 2). This is a weak type of joint although it is stronger than the butt joint because it is nailed from two sides. Its advantage is that the end grain is not exposed to damage from witer or Insects, and It has a neater appearance.

REBATED BUTT JOINT

The end of one piece fits into a rebate at the end of the other piece. This joint is strong because two surfaces are available for nailing, and because the shoulder of the rebate supports and helps to hold the other piece (Fig. 3).

The lap is the section of wood which is left projecting after the rebate is cut (Fig. 3). The lap is usually one-half of the thickness of the board. This lap will be important later when we are figuring out the length of our pieces for making a box.

The rebated butt joint is simple to construct. in the following sequence of operations we will describe how to make a simple box with this joint while also practising some techniques discussed earlier, like making a cutting list and preparing timber to size.

The tools required here will be the same ones we used for the preparation of timber; with the additions of a firmer chisel, a smoothing plane, and a backsaw. Make sure you know what these tools are and how to use them before you go on.

CONSTRUCTING A BOX WITH THIS JOINT

Step 1. Preparation of timber

Make a cutting list. The end pieces can be cut to the required length, that is the outside width of the box minus the width of the two laps. Allow 3 mm extra at each end of the side pieces, for planing off after assembly (Fig. 2).

Prepare the pieces (see Preparation of Timber section).

Step 2. Marking out

Mark the sides and ends as shown in Fig. 1, on the face edges (Marking of frames, page 88). All further jiarking will be done from the sides with these marks.

Place the two sides together and mark the position of the rebates, squaring with the try square (Fig. 2).

Mark the shoulder lines of the rebate on the inside face of the piece, using the try square (Fig. 3).

Mark the depth of the rebate on the end grain and the edge, using a marking gauge (Fig. 3). Show the waste with crosses.

Step 3. Cutting the rebate

Saw the shoulders down to the gauge line. Cut on the waste side of the line. If the piece is very wide, nail or clamp a guide over the line to guide the saw. Ut:e a backsaw (Fig. 4).

Remove the waste carefully to the gauge line with a firmer chisel (Fig. 5). Find out the direction of the grain by chiselling out small pieces first, so that you don't accidentally chisel too deep.

Step 4. Assembling

Clean up the inside faces with a smoothing plane (Fig. 6).

Assemble the box with glue and nails.

Measure the diagonals to check for squareness.

Clean up the face and bottom edges with a smoothing plane.

Plane off the waste from the sides with the smoothing plane. Prevent splintering by working inwards from the ends (Fig. 7).

HOUSED JOINT

These joints are another type of angle joint, also used in box-like constructions.

Housing consists of sinking the end of one piece into a trench which is cut into the face of another piece (Fig. 1).

The tools required for making this type of joint are the same ones used to make the rebated butt joint.

CONSTRUCTING THE JOINT

Step 1. Preparation of the timber

Make a cutting list.

Prepare the timber (see Preparation of Timber section). Step 2. Marking out

Mark one edge of the trench with a try square and the other edge by using piece A as a guide (Fig. 2). (Smooth piece A before using it to mark the trench).

Gauge the depth of the trench at each edge (Fig. 3).

Show the waste with small crosses (Fig. 3). Step 3. Cutting the trench

Saw the sides of the trench (on the waste side of the lines) down to the gauge lines (Fig. 4).

Chisel out the wasta from the trench (Fig. 5). Step 5. Assembling

Assemble the two parts with nails and glue.

Clean up the edger with a smoothing plane.

COMMON MORTICE AND TENON JOINT FOR BOX-LIKE CONSTRUCTIONS

This is one of the commonest and strongest joints. The two parts are (Fig. 1): the tenon (B) which is a projection on the end of one part and the mortice (A), the hole in the other part into which the tenon fits. The tenon is usually l/3rd of the width of the board.

The tools we need are ones we have discussed before, plus a mortice chisel, a brace and drilling bits.

CONSTRUCTING THE JOINT

Step 1. Preparation of timber

Make a cutting list.

Prepare the timber to the required sizes. (In the following steps, the piece with the mortice is "piece A" and the one with the tenon is "piece B".)

Step 2. Marking out

Mark out the length of the tenon on piece B. Allow 3 mm waste in the length and make square lines all around with a try square and pencil (Fig. 2).

Take piece A and mark out the position of the mortice on the face edge and make square lines on the edges on both sides with the try square (Fig. 3).

Set the marking gauge to the width of the tenon and mark the lines around piece B at the width. Mark the waste with small crosses (Fig. 4).

Use the same setting to mark both faces of piece A and use a try square and (already smoothed) piece B to mark the remaining two lines for the width of the mortice (Fig. 5). Mark the waste with a small cross.

If the marking gauge has two pins, set each at its correct measurement and mark both lines at onoe. If not, mark with the first setting on all the members, then change the setting and mark the other measurement on all the members.

Always mark from the face edge. Check the marking by setting piece B against the marks on piece A to see if they fit. Piece B must be smoothed first.

Step 3. Cutting the mortice

Bore out most of the waste, using a brace nud bit (Fig. 6). Clamp a piece of wood to the underside to prevent splintering and damage to the bench.

Chop out the remaining waste with a mortice chisel, chiselling halfway through from both sides. Leave about 2 mm extra waste on all sides to prevent damage to tbe sides. Keep the cutting edge of the chisel across the grain.

Carefully chop out the rest of the mortice up to the lines (Fig. 7). Keep the bevel of the chisel towards the inside of the mortice. Do not use the mallet.

Step 4. Cutting the tenon

Rip the sides of the tenon, sawing on the waste side of the line (Fig. 8). Cut in stages as shown in Fig. 11, a, b, c, &d).

Carefully saw the shoulders, making sure to hold the saw straight. Keep on the waste side of the line (Figs. 9 & 10).

Step 5. Assembling the joint

Check the fit of the members. The tenon should fit tightly into the mortice without splitting the morticed piece. There should be no gap between the shoulders of the tenon and the morticed member. Don't force the members together. If they don't fit, find the problem and correct it.

Clean up the inside of the joint where it can't be reached after assembly with a smoothing plane. (Remember that the tenon should be smoothed before using it to mark out.)

Assemble the joint.

Plane off the waste end of the tenon, clean up all sides and edges with the smoothing plane.

CORNERLOCKED JOINT

The cornerlocked joint is similar to the mortice and tenon joint. It is an angle joint with a series of tenons on one member which correspond to slots on the other member (Fig. 1). The resulting joint is strong because it can be nailed from two sides, and the interlocking tenons and slots also help hold the pieces together.

The tools required to make this joint are the same ones used for the mortice and tenon joint.

CONSTRUCTING THE JOINT

step 1. Preparation of the timber

Make a cutting list.

Prepare the timber to the required sizes. (In the following steps, the member with the slots is piece "A" and the one which has the tenons is piece "IV.)

If the members are to be used for a box whera the external appearance is important, the face sides should be outside.

In most cases the face edges are kept upwards.

Step 2. Marking out

Mark out the position of the tenons and slots by gauging or squaring lines at the corners on the ends of the pieces: on piece A the depth should be equal to the thickness of piece B (Fig. 2); while on piece B the depth should be equal to the thickness of piece A (Fig. 3). Allow 2 mm waste for cleaning up after assembly.

Mark out the shape of the tenons on piece B. Keep all tenons the same size (Fig. 4).

Immediately mark the waste between the tenons with crosses (Fig. 4).

Step 3. Cutting the tenons

Rip the sides of the tenons down to the gauge line (Fig. 5). Saw on the waste side of the line.

Chop out the waste by chiselling alternately vertically and then at an angle, making "V" cuts halfway through from each side (Figs. 6, 7, & 8).

Step 4. Cutting the slots

Place piece B (with the tenons) over the end of piece A, with the face side towards the outside as indicated in Fig. 9.

Mark the shape of the tenons onto piece A with a pencil (Fig. 9).

Square the sides of the slots down both sides (Fig. 10).

Mark the waste with small crosses (Fig. 10).

Rip the sides of the slots, sawing on the waste side of the line.

Chop out the waste from the slots, chiselling from both sides as explained in the previous step (Fig. 11).

Step 5. Assembling the joint

Clean up the inside faces of the joint.

Assemble the joint with glue and nails.

When the glue is dry, clean up the waste of the tenons and slots with a smoothing plane. Make sure the nails are punched well below the surface to prevent damage to the sole of the plane.

Clean up the outside faces and edges with a smoothing plane.

FRAMING JOINTS

Framing joints are those used in frame-like construct ions. The members are usually constructed with their edges at right angles to each other; in contrast to the angle joints used in box-like constructions, where It is the sides which form the right angle (previous pages).

HALVED JOINTS

Halved joints are one type of framing joint. The name is applied to joints where the pieces of timber which meet or cross each other are halved; that is, at the place where they cross, each piece is 1/2 the thickness of the rest of the piece. The result is that in the assembled joint, the surfaces of both pieces are flush.

Halved joints are used for constructing simple frames.

In Rural Building, we deal with four different kinds of halved joints. Here we will cover the description and construction of the "tee-halved joint", since the construction of the other joints follows much the same procedures.

The tee-halved joint consists of a pin (a) on the end of one piece which fits into a socket (b) in the other piece (Fig. 1).

The pin is half the thickness of the timber, and the depth of the socket equals the thickness of the pin. The shoulder of the pin (c) fits against the face edge of the socket (Fig. 1).

The tools required to make this joint are the same ones we used to make the mortice and tenon joint in the last chapter.

CONSTRUCTING THE JOINT

Step 1. Preparation of timber

Make a cutting list.

Prepare the pieces to the required size.

Step 2. Marking out

Mark the length of the pin by placing the socket piece on top of it and marking at the width. A small amount of waste can be left on the end of the pin, to be planed off after the joint is assembled.

Make lines square at the shoulder of the pin, drawing them across the side and halfway down the edges, with a try square and pencil (Fig. 2). Mark the waste.

Mark the position of the socket, using the piece with the pin as a guide. Smooth the pin before using it to mark the socket.

Square the lines across the side and halfway down the edges with a try square. Mark the waste (Fig. 3).

Gauge the thickness of the pin around its edges and mark the waste (Fig. 2).

With the same setting, gauge the depth of the socket on both edges and mark the waste (Fig. 3).

Both pin and socket should be gauged from the face side.

Place the pin over the position of the socket and check the fitting (Fig. 4).

Step 3. Cutting the pin

Rip the thickness of the pin. Cut in stages as shown in Fig. 5, a through d. Take care to keep on the waste side of the line.

Saw the shoulder of the pin, keeping on the waste side of the line (Fig. 6).

Step 4. Cutting the socket

Saw down to the gauge lines of the socket, keeping on the waste side of the lines (Fig. 7).

Chisel out the waste, chiselling halfway through from both edges (Figs. 8 & 9).

Test the flathess of the socket with the blade of the try square.

Step 5. Assembling the joint

Clean up the inside edges with a smoothing plane.

Assemble the joint with glue and nails.

When the joint is dry, plane off the waste of the pin.

Clean up all sides and edges with the smoothing plane.

CORNER-HALVED JOINT

Another halved joint is the corner-halved joint (Fig. 1). It is used where the pieces meet at their ends to form a corner.

The sequence of operations to construct this joint is similar to the one for the tee-halved joint, except that instead of a pin and a socket, two pins have to be marked and cut.

CROSS-HALVED JOINT

The third halved joint we deal with is the cross-halved joint (Fig. 2). It is used where two members cross each other.

The sequence of operations to construct this joint is similar to the tee-halved joint, but instead of a pin and a socket, two sockets have to be marked and cut.

STOPPED TEE-HALVED JOINT

In this joint the socket is stopped away from the edge and the pin is cut short, so that in the assembled joint the end grain of the piece is not seen (Fig. 3).

Otherwise, the same sequence is followed as for the tee-halved joint.

COMMON MORTICE AND TENON JOINT FOR FRAME-LIKE CONSTRUCTIONS

One of the most common and strongest forms of framing joint is the mortice and tenon joint (Fig. 1).

The sequence of operations to construct a mortice and tenon joint for frame-like constructions is almost the same as for box-like constructions. Of the four types of mortice and tenon joints mentioned in this chapter, we will only go into detail about the construction of one of them, the common mortice and tenon. No new tools will be needed.

CQNSTRUCTING THE JOINT

Step 1. Preparation of timber

Make a cutting list.

Prepare the timber.

Step 2. Marking out

Mark out the position of the mortice and square the lines across the face side and edges, using a try square and pencil (Fig. 2).

Mark out the length of the tenon on the other member. Allow 3 mm waste on the end.

Square lines all around (Fig. 3).

Set a marking gauge to the size of the tenon (one-third of the width of the piece) and mark around the end of the tenon (Fig. 5). Mark the waste.

Use the same setting to mark both edges of the mortice and mark the waste (Fig. 4).

Do all marking from the face side.

Check the marking, using the pieces as a guide by placing them over the marks (compare this sequence to the mortice and tenon for box-like constructions).

Step 3. Cutting the mortice

Most of the waste may be bored out (Fig. 6). Bore halfway through from both edges. Make sure you keep the brace at a 90 degree angle to the edge.

Chop out the remaining waste, cidselling halfway through from both edges. Leave about 2 mm extra to prevent damage to the sides of the mortice during chiselling (Fig. 7).

When most of the waste is out, chisel out the remainder to the line (Fig. 8).

Keep the cutting edge of the chisel across the grain. Step 4. Cutting the tenon

Rip the sides of the tenon, sawing on the waste side of the lines (Fig. 9).

Saw in steps (see tee-halved joint).

Carefully saw the shoulders, keeping the saw vertical and on the waste side of the line (Fig. 10 &11).

Step 5. Assembling the joint

Check whether the members fit together (see Assembly section for the mortice and tenon joint for box-like constructions).

Clean up inside the joint where it cannot be reached after assembly.

Assemble the joint with glue.

When it is dry, plane off the waste of the tenon.

Clean up the edges and sides with a smoothing plane.

Note the importance of marking the waste as you mark out the pieces. This cannot be over-emphasized. Most construction mistakes are made by cutting on the wrong side of the line, due to improper marking.

HAUNCHED MORTICE AND TENON JOINT

Another type of mortice and tenon for frame -like constructions is the haunched mortice and tenon (Fig. 1). This joint is used where one member meets another at a corner.

The width of the tenon is reduced to 2/3rd of the width of the board and the mortice size is reduced to suit (Fig. 1).

A haunch is left on the tenon to prevent it from twisting in the mortice. The length of the haunch is equal to the thickness of the tenon and it fits into a recess above the mortice, called the haunching.

Otherwise, the sequence of operations for construction of this kind of joint is the same as for the common mortice and tenon joint.

When you make the cutting list for this type of joint, the allowance in length for the member with the mortice should be 25 mm instead of 12 mm to help prevent splitting of the haunching.

STUB TENON JOINT

Where the end grain of the tenon and the opening of the mortice must be hidden, the stub tenon joint is chosen (Fig. 2). in this joint the tenon does not pass through the morticed member, but is stopped inside. The sequence of operations for constructing this joint is the same as for the common mortice and tenon joint. Stub tenons are also used for box-like constructions.

At times a combination of the haunched and stub tenons is required. This is called a haunched stub mortice and tenon joint.

TWIN TENON JOINT

Where the members to be joined are very thick, twin tenons are used (Fig. 3). Each tenon is then not 1/3rd, but 1/5th of the thickness of the members.

The sequence of operations is almost the same as for the common mortice and tenon joint, with the only difference being that two mortices and tenons have to be marked and cut instead of only one.

This joint can be used for both frame-like and box-like constructions.

SECURING THE JOINTS

Instead of nails to secure mortice and tenon joints, either pegs or wedges can be used.

One or two holes are drilled through the assembled joint and wooden dowels, or pegs, as they are called in this case, are inserted with glue to securely fix the join (fig. 1).

To make the dowels, plane off the corners of a square piece of hard wood, until the piece is round. When the dowel is cut to length, chamfer the ends and cut a groove along the length to permit air and excess glue to escape (Fig. 1, a - e).

Follow the steps below to secure a joint by means of wedges.

Cut the mortice with an allowance of 2 mm in width, tapering from the outside edge to about 2/3rd of its depth (Fig. 2).

Make cuts in the tenon to receive the wedges.

To prevent splitting of the tenon, drill small holes at the end of each cut.

Cut the wedges from small pieces of waste wood; they should have the same length as the tenon.

Haunched mortice and tenon joints in frame-like constructions should not be wedged, because of the danger of breaking off the small haunch at the corner of the joint.

Both wedges and pegs can be used for securing mortice and tenon joints in boxlike constructions.

BRIDLE JOINT

Bridle joints are similar to mortice and tenon joints. They consist of a pin and a socket (Fig. 1). The thickness of the pin is 1/3rd of the thickness of the member. The two types of bridle joint are the tee bridle (Fig. 1) and the corner bridle. Here we will only go into detail about the tee bridle, since the" construction of the corner bridle joint follows much the same procedure.

CONSTRUCTING THE JOINT

Step 1. Preparation of the timber

-Make a cutting list. -Prepare the timber.

Step 2. Marking out

-Mark the position of the pin on one member, making the distance between the shoulders equal to the width of the other piece. Square the lines all around the piece with a try square and pencil (Fig. 2).

-Mark the length of the socket (plus 2 mm waste) on the end of the other member, making the length equal to the width of the pin. Square the lines across the face side and on both edges (Fig. 3). Remember to smooth the pieces before using them to mark.

-Set a marking gauge to l/3rd of the thickness of the member and gauge along both edges of the pin. Use the gauge from the face side only. Mark the waste with small crosses (Fig. 4).

-With the same setting on the gauge, mark around the end of the socket. Mark the waste (Fig. 5).

-Mark the other side of the socket in the same manner, from the face side, with the gauge set at 2/3rds of the thickness of the piece. If you have a gauge with 2 pins, mark both lines at once.

-Check the fitting.

Step 3, Cutting the pin

Carefully saw the shoulders down to the gauge line, sawing on the waste side of the line (Fig. 6).

Chisel away the waste, chiselling halfway through from both edges (Fig. 7). Step 4. Cutting the socket

Rip the sides of the socket down to the required depth, sawing on the waste side of the lines (Fig. 9). Saw in steps (see Tee-halved joint, Cutting the pin, page 114).

Chop out the waste with a mortice chisel, chiselling halfway through from botn edges (Figs. 10 &11).

Step 5. Assembling the joint

Clean up the inside edges which cannot be reached after the joint is assembled.

Assemble the joint with glue and nails.

When the glue is dry, plane off the waste of the socket.

Clean up the sides and edges with a smoothing plane.

CORNER BRIDLE JOINT

The corner bridle joint is used where members meet to form the corner of a frame. Like tha tee bridle, it consists of a pin and a socket (Fig. 12).

The pin is constricted like the tenon in the sequence of operations for the mortice and tenon joint for frame-like constructions.

The socket is constructed in the same way as the socket for the tee bridle joint, above.

WIDENING JOINTS

Widening joints are joints used to make a single, wide board by joining two or more narrow boards along their length, edge to edge (Fig. 1).

The boards that will be joined must first be marked. Lay the boards out in the desired position and mark them with a triangular mark over all the boards (Fig. 1). The triangle should point upwards. This mark will help us to keep in mind the position of each board during the steps that follow.

PLAIN GLUED BUTT JOINT

This is the simplest widening joint (Fig. 2). The edges of the boards are planed perfectly straight and square, and then butted together. The joint is glued and clamped tightly to force out the surplus glue. For narrow pieces this is done with G-clamps. For wider pieces, wooden or metal sash clamps are used.

DOWELLED WIDENING JOINT

This joint is similar to the plain glued butt joint, but strength is added by means of cylindrical wooden pins, called dowels. Dowels are made as explained in the section on securing joints. The dowels are then glued into holes in the edge of each board (Fig. 3). The diameter of the dowels should be about one-third of the thickness of the pieces that are being joined.

The holes should be about as deep as the boards are thick, and they should be slightly countersunk.

Mark out the position of the dowels by puttmg the boards on top of each other, sides together and marking both edges at the same time. The centre can be marked with a marking gauge, marking from the face side.

Metal or wooden sash clamps are used to press the boards together during glueing.

REBATED JOINT

In this widening joint, the edges of the boards are rebated to match each other (Fig. 1). The rebating is done with either an ordinary rebate plane or an adjustable one. This joint is stronger than the plain glued butt joint,

HOW TO PLANE A REBATE WITH AN ORDINARY REBATE PLANE

Step 1.

Mark the depth and width of the rebate with a marking gauge (Fig. 2).

Step 2.

Fix a wooden guide strip along the line that marks the width of the rebate (Fig. 2). The guide strip must be perfectly square and It should be flat.

Step 3.

Plane until you reach the line marking the depth of the rebate. Take care that the side of the plane is always against the guide strip, so that the width of the rebate is the same along the whole length.

If you notice that you are planing against the grain, stop just before you reach the required depth and plane from the other direction. This will ensure that the surface of the rebate is smooth.

An important point in planing rebates is setting the plane correctly. The side of the cutting iron that faces the rebate must be set so it is exactly flush with or only slightly coming out at the side of the plane. If it projects too far it will damage the guide strip, and if it is set in from the side it will not plane true (Fig, 3).

When you set the cutting Iron, do not knock on it with a steel hammer. This will damage the iron. Rather, loosen the wedge slightly and knock it with a mallet or a piece of wood.

When the rebate plane is not set well, it will tend to slip off the rebate and will not produce a good surface.

HOW TO PLANE A REBATE WITH AN ADJUSTABLE REBATE PLANE

To make work simpler, we can fix guides onto the rebate plane itself. Thus, fixing guide strips on the boards is unnecessary (Fig. 1).

One wooden piece is fixed on the sole of the plane (B) at the standard width for rebates and another piece is fixed on the side of the plane (A) and can be moved up or down to adjust the depth of the rebate. The width can also be adjusted, by using a wider or narrower wood guide (Fig. 2).

The guides should not be nailed to the plane, since that would damage it. They should be fixed by bolts and nuts, so that they can be easily removed.

Plane until the depth guide just touches the work. Take care that the width guide is always firmly pressed to the side of the timber. If you notice that you are planing against the grain, stop just before you reach the required depth and finish planing with the guide strips removed, which enables you to plane in the other direction. This gives a good surface to the rebate.

See the section on the ordinary rebate plane for tips on how to set the cutting iron.

LOOSE TONGUED JOINT

This joint is used where a joint stronger than the plain glued or rebated joint is needed. The boards to be joined must be at least 2 cm thick (Fig. 3).

The joining edges are grooved and a tongue is glued into the grooves. The depth of the groove is about 2/3rd of the thickness of the board. The width of the groove is equal to the thickness of the tongue. The groove should be slightly deeper than the projection of the tongue, to allow for expansion (Fig. 4).

Plywood makes a very strong tongue and it is frequently used for this purpose.

If solid wood is used as a tongue, care must be taken that it is always cut across the grain. A tongue cut with the grain will make a weak joint.

HOW TO PLANE A GROOVE FOR A LOOSE TONGUED JOINT

Usually special planes called plough planes are used to plane grooves for this kind of joint. If a plough plane is not available, we can adapt our rebate plane for this purpose and make an improvised plough plane (Fig. 1).

To do this, grind and sharpen the narrow end of the rebate plane cutting iron to make a cutting edge. Grind the sides of the iron to the size of the most commonly used tongue, which is 6 rnm plywood. The sides should be slightly bevelled to ensure free movement in the groove.

When the iron is fitted into the plane it is adjusted so that the cutting edge projects out of the sole by exactly the required depth of the groove.

A guide, similar to the one used for the adjustable rebate plane, is now fitted to the side of the plane. This guide keeps the cutting iron at the right distance from the face side of the boards. It should be adjusted according to the most common thickness of the boards, in this case it is about 22 mm for a planed board. For a tongue size of 6 mm then, the distance between the edge of the guide ai J the edge of the cutting iron will be 8 mm.

When planing press the guide firmly against the side of the wood and hold the plane exactly at a right angle to the edge of the board.

The most difficult part will be to start the groove, since the cutting iron will tend to slip off the edge and it requires some experience to keep it steady. Go slowly at first.

Work from the face side at all times.

To prevent injuries cover the cutting edge where it sticks out of the top of the plane.

MISCELLANEOUS CARPENTRY TECHNIQUES

MARKING A BOARD TO FIT AN IRREGULAR SURFACE

To mark the edge of a board which you want to fit against an irregular surface such as an unplastored wall, hold the board firmly and level to the wall and mark it with a compass or a similar device as shown in Fig. 1.

As one leg of the compass moves along the wall, the other leg will mark on the board an exact copy of the irregularities of the wall surface. The legs of the compass have to be set apart by a distaace a little greater than the width of the biggest gap between the wall and the board.

If no compass is available, a small wooden block can be used instead (Fig. la). The pencil is held in the notch at one end and the other end is moved along the surface of the wall.

MEASURING THE WIDTH OF OPENINGS

A convenient way to measure the width of openings such as doors and windows is to use two sticks as shown in the illustration (Fig. 2) to just span the opening. Then transfer the measurement to a single board by marking and measure it with a rule.

MARKING OUT IRREGULAR DESIGNS WITH TEMPLATES

When you want to mark out several pieces with the same irregular shape, you can save time and ensure more accurate work by marking from a template (Fig. 3). Templates are thin pieces of cardboard or plywood onto which the required pattern is drawn and then cut out.

The template is used by placing it on the material to be marked and holding it firmly in place while drawing around it.