by small wedges. The mortise is slightly dovetailed and two saw cuts are
made in the tenon about 3/16 in. from each side. Into each saw kerf a
wedge is inserted and the joint glued up. The cramping operation forces
the wedges into the saw cuts, thus causing the end of the tenon to spread
and tightly grip the mortise.
MORTISE AND TENON WITH MITRED FACE (Fig. 159).--This is a useful method
of jointing framing which has square edges as shown; and it is equally
useful even if the face edges have moulds worked upon them. If the joint
has square edges a rebate may be formed to accommodate a panel by fixing
a bolection moulding around the frame. A section of the bolection mould
planted on the frame is shown in the lower figure.
[Illustration: Fig. 159.--Tenon Joint with Mitred Face.]
[Illustration: Fig. 160.--Rafter Joint.]
[Illustration: Fig. 161.--Roof Joints.]
ROOF JOINTS.--Fig. 160 shows the method of tenoning the principal rafter
to the king post, whilst Fig. 161 illustrates the tenoning of the struts
to the king post, and the king post to the tie beam. Both these examples
are used in roof work. (See also Fig. 71.)
[Illustration: Fig. 162.--Drawbore Pinning.]
[Illustration: Fig. 163., Fig. 164. Operation of Pegs in
Drawbore Pinning.]
DRAWBORE PINNING.--At Fig. 162 is seen the method of securing a tenon by
drawbore pinning, employed when it is not convenient to obtain the
necessary pressure by using a cramp. The joint is made in the usual
manner, and a 3/8-in. twist bit is used to bore a hole through piece A.
The tenon is driven home and the hole is marked on the side of the tenon
(B); the tenon is then withdrawn and the hole bored about 1/8 in. nearer
to the shoulder than as marked on the separate diagram at C. When the
tenon is finally inserted the holes will not register correctly, and if a
hardwood pin be driven into the joint it will draw the shoulders of the
tenon to a close joint and effectually secure the parts.
SASH BARS.--Fig. 165 shows how to tenon a moulded sash bar to the rebated
cross rail. In this illustration both shoulders of the moulded bar are
shown square, but in the best class work these shoulders may be slightly
housed into the cross rail to prevent side play. This type of joint is
used for horticultural buildings, etc. If the lower rail be moulded with
the same members as the sash bar, the end of the sash bar will have to be
scribed on to it to make a fit.
[Illustration: Fig. 165.--Tenoning Moulded Sash Bar.]
[Illustration: Fig. 166.--Tenon with Tongued and Grooved Shoulder.]
[Illustration: Fig. 167.--Detail of Table Framing.]
TENON WITH TONGUED AND GROOVED SHOULDERS (Fig. 166).--The object of the
tongues and grooves here is to prevent the face of the work casting, or
becoming warped, and thus spoiling the appearance of the surface of the
work. If framing is to be veneered on the face side this is an
exceptionally good method.
TABLE FRAMING.--Fig. 167 indicates the framing of a rail to a
dining-table leg. In cases similar to this the tenons run into the leg
and almost touch each other. They are therefore mitred on the end as
shown in the inset. Chair frames often call for similar treatment.
TWIN TENONS with haunch, as used when the timber is of great thickness,
are shown in Fig. 168.
AN OPEN SLOT MORTISE at the end of a right-angled frame is seen in Fig.
169. Fig. 170 shows an open slot mortise and tenon joint at the end of a
frame of 60°. Both these joints are occasionally called end bridle
joints.
[Illustration: Fig. 168.--Twin Tenons for Thick Timber.]
[Illustration: Fig. 169.--The Open-slot Mortise Joint.]
HAMMER HEAD TENONS.--At Fig. 171 is shown the method of jointing framing
having semicircular or segmental heads. The left-hand diagram indicates
the method of wedging the joint so as to draw up the shoulders; the
right-hand view shows the tongueing of the shoulders, which is necessary
if thick timber has to be wrought. The sketch depicts the stile when
taken apart from the shaped head of the frame.
CLAMPING.--Fig. 172 shows the method of tenoning drawing boards, desk
tops and secretaire falls. This is commonly called clamping. The method
is used to prevent wide surfaces from winding. A variation of the joint
is shown at the left-hand side, the corners in this example not being
mitred. Fig. 173 shows the tenoning of a wide to a narrow rail when the
joint is at an angle.
INSERTED TENONS (Fig. 174).--Where two pieces of timber run together at
an acute angle it becomes necessary to use inserted tenons. Both pieces
of the timber are mortised and the inserted tenons are secured into the
widest piece. On the left is shown the inserted tenon, secured by the
method known as fox-wedging; on the right the inserted tenon has been let
into the wide rail from the edge. The narrow rail is secured by wedging
the tenons from the outside edge in the ordinary manner.
[Illustration: Fig. 170.--Open-Slot Mortise at 60 degrees.]
[Illustration: Fig. 171.--Hammer-Head Tenon Joint.]
DREADNOUGHT FILE.--At Fig. 175 is a sketch of a portion of a dreadnought
file. This has superseded the old-fashioned home-made float used to clean
out the sides of a mortise.
[Illustration: Fig. 172.--Clamping.]
[Illustration: Fig. 173.--Tenoning Narrow Rail.]
[Illustration: Fig. 174.--Inserted Tenons.]
[Illustration: Fig. 175.--Dreadnought File.]
[Illustration: Fig. 176.--External and Internal Joints.]
[Illustration: Fig. 177.--Setting out Stiles and Rails for Tenoning.]
GENERAL RULE.--In practically all cases where a single tenon is used the
thickness of the tenon should be one-third the thickness of the timber.
This leaves the timber at each side of the mortise the same strength as
the tenon.
Mortise and tenon joints for inside work may be united with glue. If,
however, the work has to stand the weather a better method is to unite
the joint with white lead, which is run down to the required consistency
with good outside varnish.
SETTING OUT THE JOINT.--The principal use of the mortise and tenon joint
is in the construction of various types of framing, such as door and
window frames. In one or other of its many and varied forms it may be
classed as the most important joint in the general woodworking trade. The
joint may be used as an internal one, as shown at the lower rail, Fig.
176, or as an external joint, as the upper rail of the same illustration.
Whatever type of framing has to be made, it is necessary that the face
side of the wood be planed up straight and out of winding, and the face
mark (as shown in Fig. 176) pencilled upon it. The best edge of the
timber should next be planed up true in length, and square to the face
side, and the edge mark (X) clearly placed upon it.
The marking gauge is now set to the desired width, and gauge lines are
marked on the wood, after which the waste wood is planed off until the
timber is the required width. The thickness is gauged and treated in a
similar manner, except in such cases where the finished work is to be of
a rough and ready character.
THE TWO STILES (or uprights) have their faces turned to touch each other,
as shown at Fig. 177, and their length may be anything from 1 in. to 3
ins. longer than the required finished size. This waste wood at each end
of the stiles (see arrow HO) is of importance to the work, as it prevents
to a great extent the bursting of the mortise whilst cutting the hole or
when knocking together the work. The small projection is called the
"horn," and it is cut off after the frame has been put together.
[Illustration: Fig. 178.--Setting Out the Stiles with Marking Knife.]
[Illustration: Fig. 179.--How to Saw the Tenons--First Operation.]
THE TWO CROSS RAILS (Fig. 177), have their faces placed together as shown
in the sketch. These rails may with advantage be left 1/2 in. longer than
the finished size, and the portion of the tenon (which will protrude
through the stile 1/4 in. at each end) may be cut off after the work is
put together. (See Fig. 92.)
Set out the stiles with a marking knife or penknife and a try square, as
shown at Fig. 178. In this sketch only one stile is shown for clearness
of representation, but two or more stiles (as at Fig. 177) may be marked
out at the same time, provided a 12-in. try square be used; in fact,
marking out the stiles in pairs is to be recommended, as all cross lines
will be exact owing to their being marked at the same operation. The cut
made by the marking knife should be lightly carried all round the work as
the mortising is cut from each edge of the stile, the cutting of the
mortising being finished in the centre. The lettering on Fig. 177 is as
follows:--HO, horn; M, position of mortise; H, position of haunching; A,
inside line, or sight size, as it is occasionally called.
Set out the cross rails as at Fig. 177, lower sketch. The lettering in
this figure is as follows:--T, tenons; the small piece of the tenon
lettered J is called the haunch, and the shaded portion H is cut away to
allow the haunch J to fit the haunching of the stile.
THE TENONS (as already stated) are generally one-third the thickness of
the timber, thus leaving the same amount of substance at each side of the
tenon as the tenon itself is composed of. The mortise gauge is set to the
required distance and used as in the case of the marking gauge (Fig.
82).
[Illustration: Fig. 180.--Second Operation in Sawing Tenons.]
[Illustration: Fig. 181.--Cutting Channel at Shoulder of Tenon before
Sawing.]
To saw the tenons, place the rail in the vice as at Fig. 179 and, with a
panel, tenon, or hand saw, according to the size of the work, cut down
the outside of the tenon line as shown. Reverse your position and cut as
shown at Fig. 180, then place the rail in a vertical position, and you
will find little or no difficulty in sawing down square with the shoulder
line. Repeat the above methods of sawing until all the tenons are sawn.
Next saw out the pieces at the side of the tenon by the following
procedure. Place the rail against the bench stop, or in the vice, and cut
a small channel in which to run your tenon saw as shown at Fig. 181. If
you have scored the line deeply with your knife when you were marking out
the work, you will have little difficulty in removing a small portion
with the chisel. The amount removed in the illustration is, of course,
exaggerated. In the small channel thus made place the tenon saw and,
guiding the saw blade with the finger so as to keep it upright or square
(Fig. 182), saw away the waste material. Remove the waste material at the
sides of the tenons in a similar way, and then saw out the portion marked
H, Fig. 177, lower sketch.
THE MORTISING of the stiles may next be taken in hand by putting the
stiles edgeways in the vice and boring away the bulk of the waste wood
from the mortise with a suitable-sized twist bit and brace. This method
will save a great amount of noise, as to a great extent it does away with
the use of the mallet. Take the mallet and chisel and chop down about 3/8
in. as shown at Fig. 183; then turn the chisel to the position shown at
Fig. 184 and remove the small piece as shown. Continue these two
operations until you are about half-way through the wood and then start
in a similar manner at the line _a_, Fig. 183, after which turn the other
edge of the timber uppermost and repeat the methods shown.
[Illustration: Fig. 182.--Sawing away Waste Material.]
[Illustration: Fig. 183.--Using the Chisel and Mallet for Mortising.]
Fig. 185 shows the sketch of a mortise which has its side removed so as
to show the method of successive cuts with a chisel when removing the
core from a mortise; this, in conjunction with the other sketches,
clearly shows the methods of working. In many woodwork examinations the
examiners insist that the mortise shall be removed by successive cuts
with the chisel, but we certainly advise the removal of much of the waste
wood with a boring bit, provided the worker can keep straight and well
within the limitations of his gauge lines.
[Illustration: Fig. 184.--Removing Waste of Mortise with Chisel.]
REMOVING HAUNCHING.--After removing the mortise hole, the small portion
which is called the haunching will require to be removed with a chisel.
This calls for no special remark, as it is clearly shown in Figs. 187 and
188. Fig. 186 shows an everyday type of mortise and tenon joint
separated; it is used in cases where a straight joint is required on the
upper or lower edge of the work, whereas the upper rail of Fig. 176 shows
the full haunch on the top edge. In cases such as Figs 187 and 188, where
the edges of the frames are grooved to receive panels, etc., the width of
the tenon is reduced by the width of the groove.
[Illustration: Fig. 185.--Mortise with Side Removed.]
[Illustration: Fig. 186.--The Joint Separated.]
[Illustration: Fig. 187.--Removal of Haunching.]
[Illustration: Fig. 188.--Haunching with Groove above.]
This must be remembered by the worker when marking out his stiles with
the marking knife. Fig. 187 (right-hand sketch) shows the haunch, tenon,
and groove G at the bottom. Fig. 188 (left-hand illustration) shows G
(groove) at top, and HH (the haunch) at the bottom. Tenons may be glued
together and wedged as shown at Fig. 176 if for inside work; but if for
outside work they are generally smeared with thick paint and wedged up.
For light-class cabinet work it is usual to cut the mortise about
seven-eighths of the distance through the stile and make the tenon to
match it; the edge of the finished work does not then show any indication
of the joint, and it leaves a nice clean surface at the edge of the work
for polishing or varnishing.
[Illustration: Fig. 189.--Interlocking Joint for Seat Rails of Chair to
Leg.]
INTERLOCKING CHAIR JOINT.--A joint designed with a view to strengthening
the construction of chairs at the point where they are weakest is shown
in Fig. 189. The joint is an interlocking one so arranged that, once the
chair is glued up, no motion of the side rail can be possible. The groove
in the side rail tenon is cut in such a manner that, on the insertion of
the back rail tenon, the joint actually draws up and, having done so, is
locked in position. The exact location of this groove is obtained in a
similar manner to that used in marking out tenons for drawbore pinning,
_i.e._, the tenon is inserted in its mortise and the position of the back
rail mortise transferred to it, after which the lines are set back by
1/64 in. (approximately) to cause the joint to draw.
From the illustration the construction of the joint should be clear. The
method is particularly adapted to a section of rectangular form where one
side is longer than the other, such as the back leg of a chair, as this
shape allows for the accommodation of the extra length of tenon
required.
THE DOWELLING JOINT
Dowelling is the term generally given to the method of jointing timber
and other materials by wooden or metal pegs, which are called dowels. For
cabinet-making and similar work straight-grained beechwood dowels are
mostly used; these may be bought by the gross, in lengths of about 36
ins., and of any desired diameter.
[Illustration: Fig. 190.--Steel Dowel Plate.]
MAKING DOWELS.--Many, however, prefer to make what they require for the
work in hand, and the following is the method that is generally employed.
Pieces of straight-grained wood are wrought to a square section, after
which the corners are planed away to form an octagonal section. The sharp
corners are now planed away, and the roughly formed dowel is driven
through a steel dowel plate, Fig. 190, by the aid of a heavy hammer, thus
giving the necessary roundness and finish to the dowels. When hammering
dowels through a plate the hammer should on no account be allowed to come
in contact with the face of the dowel plate, or the cutting edge of the
hole will be spoilt. Simply drive the dowel to within 1/8 in. of the
plate and knock it out with the next dowel.
[Illustration: Fig. 191.--Cradle for Planing Dowels.]
[Illustration: Fig. 192.--Dowel with Groove.]
[Illustration: Fig. 193.--Sawing Groove in Dowel.]
To plane off the corners a "cradle" (Fig. 191) is made and kept for the
purpose. The advantage of this cradle is obvious, preventing as it does
any tendency of the partly-formed dowel to slip or wobble. A jig, or
cradle, is easily made by bevelling the edges of two separate pieces of
wood and then glueing and screwing them together as at Fig. 191. A small
block of wood is inserted to act as a stop whilst the planing operation
is in progress. It is usual to bevel both edges of the timber from which
the cradle is formed, thus accommodating all sizes of dowels from 1/4 in.
to 5/8 in. in diameter.
[Illustration: Fig. 194.--Pricking the Centres ready for Boring. Also
showing how Brace is used in conjunction with Try Square.]
Fig. 192 shows a completed dowel with a small groove running along its
entire length. The object of this groove is to allow the air and
superfluous glue to escape and thus avoid splitting the work on hand; the
groove also secretes a certain amount of glue, which increases its hold
on the timber.
Fig. 198 illustrates the method of marking out and gauging two boards for
dowelling. The edges of the boards are first shot to a true joint; then
the face sides are placed together and the lines for the dowels are
marked across the edges with a fine pencil and the aid of a try square.
The boards are then gauged from the face side, thus giving the points
indicated in the sketch.
[Illustration: Fig. 195.--Countersink.]
[Illustration: Fig. 196.--Dowel Rounder.]
[Illustration: Fig. 197.--Twist Bit.]
To start the twist bit (Fig. 197) it is a good plan to prick the board at
the point of intersection of the marked lines with a sharp,
circular-pointed marking awl. This obviates any tendency of the boring
bit to run out of truth and thus cause unevenness on the face side of the
jointed board. (See Fig. 194.)
A safe rule for the spacing of dowels when jointing sideboard tops,
dressing table and wardrobe ends, etc., is to place the dowels 9 ins. to
10 ins. apart, and place two dowels at each end as shown at Fig. 198. The
length of the dowels should be about 7/8 in. to 1-1/4 in. long.
Fig. 199 shows the two boards prepared ready for glueing. The back one
is bored to receive the dowels, and the front one shows the dowels glued
in position. It is customary to warm the edges of the boards before
spreading the glue, and cramps are required to squeeze the joint tight.
These should be left on the jointed board from one to four hours
according to the state of the weather. In cases where thick timber (say
2-in. or 2-1/2-in. boards) is to be jointed, two rows of dowels may be
used, the position of the dowels being as Fig. 200.
[Illustration: Fig. 198.--Marking and Gauging Boards for Dowelling.]
[Illustration: Fig. 199.--Dowelled Joint ready for Glueing.]
Fig. 201 shows the plan of a 3-in. cornice pole made to fit a bay window;
the straight portions of the pole are generally turned in the lathe, the
corner portions being afterwards jointed and worked up to the required
shape. To avoid any difficulty in the setting out of the dowels, a disc
of cardboard or sheet metal is made to the same diameter as that of the
cornice pole; this disc is called a template. The positions of the dowels
are set out geometrically, and the centres are pricked through with a
fine-pointed marking awl (see sketch of template, _a_, Fig. 201). The
template is put on the ends of the straight pole, and the dowel centres
are pricked into the wood. The process is repeated on the ends of the
corner block (_b_, Fig. 201), and if the holes be now bored at the
centres indicated a true fit will be obtained.
[Illustration: Fig. 200.--Method of Dowelling Thick Timber.]
[Illustration: Fig. 201.--Method of Dowelling Cornice Pole by Means of
Template.]
Fig. 201 _c_ shows two portions of the circular pole jointed up to a
corner block, and the dotted lines P indicate the direct line of pressure
and shows the position for the cramp. When the glue is thoroughly set the
corner block is sawn and spokeshaved to the desired shape as shown by the
dotted line. This method is illustrated to show that, by the use of a
suitable template, dowels may be exactly set out even when there is no
straight or square face from which to use a marking gauge, and the method
may, of course, be applied to many other examples of dowelling at the
discretion of the workman.
[Illustration: Fig. 202.--Dowelling a Mitred Frame.]
[Illustration: Fig. 203.--Method of Frame Dowelling. (Long and Short
Shoulders.)]
[Illustration: Fig. 204.--Table Leaf with Dowels.]
[Illustration: Fig. 205.--Block for Twist Bit.]
[Illustration: Fig. 206.--Dowelling for Moulded Frame.]
[Illustration: Fig. 207.--Cap.]
Fig. 202 shows one corner of a mitred and dowelled frame. It needs
little or no explanation beyond the fact that the dowels should be at
right angles to the line of joint, and consequently the dowel at the
outside edge of the frame will have to be much shorter than the others.
This gives a strong and serviceable joint, suitable for many purposes.
FRAME DOWELLING.--Fig. 203 shows one corner of a frame with long and
short shoulders, such as occurs when the upright is rebated through its
entire length. The holes in both pieces are bored for the dowels before
they are rebated. This avoids any difficulty in endeavouring to bore with
only one side of the twist bit in the wood. A similar type of joint is
used on nearly all kinds of glass and door frames in cabinet work.
Fig. 204 is a leaf for the screw type of table. Circular dowels are shown
at one end, and rectangular wooden pegs at the other; both methods are
equally good, and, of course, the dowels are only glued into one leaf.
The object of these dowels is to guide the table leaf into its proper
position when the leaf engages the table proper, and to make the flat
surface of the table top and leaf register correctly and thus ensure a
level surface.
Fig. 205 is a wooden block made in two portions and held together by
screws; it is used to fasten around a twist bit, the object being to
ensure that all the dowel holes are of uniform depth. It may be adjusted
as desired and firmly screwed round the twist bit; if the hole is made
1/4 in. in diameter it will clip round a 1/4-in. or 3/8-in. bit and will
answer a dual purpose. It is a preventative for bad dowelling.
Fig. 206 is an example of dowelling framing when the moulding on the edge
has to be mitred. It is necessary to cut the shoulders away so as to
allow the members of the moulding to intersect. The section of the mould
is not shown in the sketch for clearness of representation. The portion
marked H is called the "horn," and it is not cut off until after the
frame is glued up; its object is to prevent the rail splitting or
bursting when knocking up the frame or during the cramping process.
Fig. 207 shows the method of dowelling a moulded cap to the top of a
wooden bedstead post or similar pillar where it is desired to avoid any
unsightliness.
Fig. 208 is a dining-table leg and portion of the framing, showing the
method of dowelling the frame to the leg. Chairs, couch frames, etc., are
made in a similar manner.
Fig. 209 shows the top portion of a table leg and a home-made dowel
gauge. The gauge is made of any hardwood, and steel wire pins are driven
through at the required positions and sharpened similar to the spur of a
marking gauge. The legs are sawn and planed up true and square, and the
advantage of the gauge is that all legs are marked exactly alike and are
therefore interchangeable until glued up. A gauge of this type is easily
and quickly made and may be kept for its specific purpose or altered for
other work.