By : Mr. Sunil Kumar Ojha
Mechanical Engineering Department
JRE Group of Institutions, Greater Noida
Carpentry deals with the construction of work
such as making roofs, floors portions etc of a
building , doors, windows, trusses, workbenches,
house hold furniture and many other useful
articles by means of suitable wood.
The term joinery is used for connecting the
wooden parts with the different joints such as
making doors, stairs, furniture and many other
The timber is the material used for carpentry and
Wood obtained from exogenous tree by cutting
these trees after their full growth and made
suitable for engineering or building purposes by
sawing and converting into various suitable
Advantages of Timber
1. It is very easy to be worked with tools to
give it desired shape and size.
2. Structural connections and joints can be
easily made .
3. It is lighter in weight.
4. In framed structure , it suites equally well
both load bearing and non load bearing
5. In timber work, cost of material as well as
construction both are minimized as compared
to the other materials of similar use.
6. It responds very well to polishing and
Advantages of Timber
7. It suites very favorably to doors, windows,
cabinet work furniture an decorative designs
8. It is quit suitable for making sound proof
9. It, being non conductor of heat, is favoured for
the construction of houses. Such houses will
remain warm in winter and cool in summer.
10. It provides combination of strength, durability,
lightness and economy as compared to other
materials of construction.
Disadvantages of Timber
Diminish due to rusting
Destroyed and decay due to attack of insects, fungi,
Timber swell and undergoes shrinkage with changing
Uses of Timber
Piles, post, beam, door –windows, roof member,
Truss, paneling, ceiling, partition wall, frame work,
scaffolding, transmission poles, wagon and
coaches, bridges, boat, ships, agricultural implants,
sports goods, musical instruments etc.
Classification of Trees
Exogenous Tree or Outer growing
(a) Conifer or Evergreen Tree (Soft Wood)
(b) Deciduous ( Hard Wood)
2. Endogenous Tree or Inwards Growing
Exogenous trees grow in width by forming a new
layer of wood under the bark.
Endogenous trees grow by forming new fibers
within the trunk interspersed with the old fibers.
Structure of Timber Tree
Inner Bark or Bast
Outer Bark or Cortex
Characteristics of Soft Wood and
1. It is resinous wood
having a fragrant smell
and regular texture.
2. Straight fiber and good
3. Light in colour and
4. annual rings are
5. Good tensile strength
It is non-resinous
wood containing a
fairly good amount
Fibers are quite
close and compact.
Dark in colour and
heavy in weight.
Annual rings are not
Good tensile as well
as shear strength.
6. Get split quickly
7. Weaker and less
8. Catch fire soon
cannot withstand high
9. It is easy to be
6. Does not split
7. stronger and more
8. It has an added
advantage in its
9. It is difficult to be
Defects in Timber
Exp: Knots, Shakes, Twisted Fibers, Rind Galls etc.
(b) Defects Occurring During Conversion,
Seasoning or Use
Exp: Shakes, Distortion, case hardening, Honey Combing
(c) Defects Due to action of Fungi or Insects
Exp: Dry rot, Wet rot
CHEMICAL STAIN:-THE WOOD
IS SOMETIMES DISCOLOURED BY
THE CHEMICAL ACTION CAUSED
WITH IT BY SOME EXTERNAL
AGENCY.THIS IS KNOWN AS
RIND GALLS:-THE RIND MEANS
BARK AND GALL INDICATES
PECULIAR CURVED SWELLING
FOUND ON THE BODY OF TREE
ARE KNOWN AS RIND GALL.THEY
DEVELOP AT POINTS FROM WHERE
BRANCHES ARE IMPROPERLY CUT
OFF OR REMOVED.THEY ARE
RARELY FOUND IN A TREE AND THE
COARSE GRAIN:-IF THE TREE GROWS
RAPIDLY,THE ANNUAL RINGS ARE WIDENED.IT IS
KNOWN AS THE COARSED GRAIN TIMBER AND
SUCH TIMBER POSSESSES LESS STRENGTH
KNOTS:-THESE ARE THE BASES
OF BRANCHES OR LIMBS WHICH
ARE BROKEN OR CUT OFF FROM
THE TREE.THE PORTION FROM
WHICH THE BRANCH IS REMOVED
RECIEVES NOURISHMENT FROM
THE STEM FOR A PRETTY LONG
TIME AND IT ULTIMATELY RESULTS
IN FORMATION OF DARK HARD
RINGS WHICH ARE KNOWN AS
KNOTS.AS CONTINUITY OF WOOD
FIBRES ARE BROKEN BY
SHAKES:-THESE ARE LONGITUDINAL
SEPERATIONS IN WOOD BETWEEN
THE ANNUAL RINGS.THESE ARE
CRACKS WHICH PARTLY OR
COMPLETELY SEPARATE FIBRES OF
WOOD.THE SEPERATIONS MAKE THE
WOOD UNDESIRABLE WHEN
APPERANCE IS IMPORTENT
STAR SHAKES:-THESE ARE CRACKS
WHICH EXTEND FROM BARK
TOWARDS THE SAP WOOD.THESE ARE
USUALLY CONFINED UPTO THE PLANE
OF SAP WOOD.THESE ARE WIDER ON
OUTSIDE ENDS AND NARROWER ON
INSIDE ENDS.THEY ARE
USUALLYFORMED DUE TO EXTREME
HEAT OR SEVERE FROST DURING THE
CUP SHAKES:-IT APPEARS AS CURVED
GROWTH OF TREE
SPLIT WHICH PARTLY OR WHOLLY
SEPERATES ANNUAL RINGS FROM
ONE ANOTHER.IT IS CAUSED DUE TO
EXCESSIVE FROST ACTION ON SAP
PRESENT IN THE TREE ESPECIALLY
WHEN THE TREE IS YOUNG
HEART SHAKES:-THESE CRACKS OCCUR
IN CENTRE OF CROSS-SECTION OF TREE
AND THEY EXTEND FROM PITH TO SAP
WOOD IN DIRECTION OF MEDULLARY
RAYS.THESE CRACKS OCCUR DUE TO
SHRINKAGE OF INTERIOR PART OF TREE
WHICH IS APPROACHING MATURITY.THE
HEART SHAKE DIVIDE THE TREE CROSSSECTION INTO TWO OR FOUR PARTS.
RING SHAKES:-WHEN CUP SHAKES
COVER THE ENTIRE ,THEY ARE
KNOWN AS RING SHAKES
TWISTED FIBRES:-THESE ARE KNOWN AS
WANDERING HEARTS AND CAUSED BY
TWISTING OF YOUNG TREES BY FAST
BLOWING WIND.THE TIMBERS WITH TWISTED
FIBRES IS UNSUITABLE FOR SAWING
UPSETS:-THESE INDICATE WOOD FIBRES
WHICH ARE INJURED BY CRUSHING OR
COMPRESSION.THE UPSETS ARE MAINLY
DUE TO IMPROPER FELLING OF TREE AND
EXPOSURE OF TREE IN ITS YOUNG AGE
TO FAST BLOWING WIND
BURLS:-THEY ARE PARTICULARLY
FORMED WHEN A TREE RECIEVES SHOCK
OR INJURY IN ITS YOUNG AGE.DUE TO ITS
INJURY,THE GROWTH OF TREE IS
COMPLETELY UPSET AND IRREGULAR
PROJECTIONS APPEAR ON THE BODY OF
BLUE STAIN :-THE SAP OF WOOD IS
STAINED TO BLUISH COLOUR BY THE
ACTION OF CERTAIN TYPE OF FUNGI
BROWN ROT :-THE TERM ROT IS USED
TO INDICATE DECAY OR DISEASE OF
TIMBER,THE FUNGI OF CERTAIN TYPE
REMOVES CELLULOSE COMPOUNDS
FROM WOOD AND HENCE WOOD
ASSUMES THE BROWN COLOUR
WHITE ROT:-IT IS JUST OPPOSITE OF
BROWN ROT.IN THIS CERTAIN TYPE OF
FUNGI ATTACK LIGNIN OF WOOD AND
WOOD ASSUMES THE APPEARANCE OF
A WHITE MASS CONSISTING OF
HEART ROT:-THIS IS FORMED WHEN
BRANCH HAS COME OUT OF THE TREE.IN
SUCH CASE,THE HEART WOOD IS
EXPOSED TO ATTACK OF ATMOSPHERIC
AGENTS.ULTIMATELY THE TREE BECOMES
WEAK AND IT GIVES HOLLOW SOUND
WHEN STRUK WITH HAMMER
WET ROT:-SOME KIND OF FUNGI
CAUSEDCHEMICAL DECOMPOSITION OF
WOOD OF TIMBER AND IN DOING SO
CONVERT TIMBER INTO GREYISH BROWN
POWDER.IT IS KNOWN AS WET ROT. SOME
IMPORTANT POINTS TO BE REMEMBERED
ABOUT WET ROT ARE.
THE ALTERNATE WET AND DRY CONDITIONS FAVOURS THE
DEVELOPMENT OF WET ROT
IF UNSEASONED OR IMPROPERLY SEASONED TIMBER ARE
EXPOSED TO RAIN AND WIND,THEY BECOME EASILY LIABLE FOR
ATTACK OF WET ROT.
TO PREVENT WET ROT,THE WELL SEASONED TIMBER SHOULD
BE USED FOR EXTERIOR WORK OR FOR UNDERGROUND WORK
DRY ROT :- SOME TYPES OF FUNGI FEED
ON WOODS AND DURING FEEDING THEY
ATTACK ON WOOD AND CONVERT IT INTO
DRY POWDER FORM.THIS IS KNOWN AS
DRY ROT.THE FOLLOWING FACTS TO BE
DRY ROT OCCURS AT THE PLACES WHERE THERE IS NO FREE
CIRCULATION OF AIR SUCH AS IMPROPERLY VENTILATED
BASEMENTS,ROOMS ETC AND DAMPED SITUATION LIKE KITCHEN
THE UNSESONED SAP WOOD ARE EASILY ATTACKED BY DRY ROT.
THE FAVOURABLE CONDITIONS FOR GROWTH OF FUNGUS CAUSING
DRY ROT ARE ABSENCE OF SUNLIGHT,DAMPNESS,PRESENCE OF
SAP,STAGNANT AIR AND WARMTH.
IT IS ALSO CAUSED BY CHARRING,PAINTING AND TARRING THE
THE DRY ROT MAY BE PREVENTED BY USING WELL SEASONED
TIMBER FREE FROM SAP.
WHEN A PART OF TREE IS SERIOUSLY AFFECTED BY DRY ROT,THE
THEY FORM PIN HOLES OF SIZE ABOUT 2MM
DIA IN WOOD
TUNNEL FORMATION IS DONE IN SAP WOOD BY
LARVAE OF BEETLE
CONVERSION OF TIMBER INTO FLOUR LIKE
THEY DO NOT DISTURB OUTER SHELL OR
THEY ARE FOUND IN SALTY WATER
THEY FORM TUNNELS OR BORES TO TAKE SHELTERS
DIAMETER AND LENGTH OF HOLES ARE AS HIGH AS
25MM AND 60 MM RESPECTIVELY
AFFECTED WOOD LOOSES ITS COLOUR AND STRENGTH
NO TIMBER IS COMPLETELY IMMUNE FROM ATTACK OF
LIVES IN COLONY AND VERY FAST IN EATING AWAY
THE WOOD FROM CORE OF CROSS-SECTION.
MAKES TUNNELS IN DIFFERENT DIRECTIONS AND
USUALLY NOT DISTURB THE OUTER SHELL OR
THE TIMBER PIECE ATTACKED BY TERMITES MAY
LOOK SOUND UNTILL IT COMPLETELY FAILS
FEW GOOD TIMBERS LIKE TEAK,SAL,ETC CAN
CHIP MARK:-THIS DEFECT
IS INDICATED BY MARK OR
SIGNS PLACED ON
FINISHED SURFACE OF
TIMBER.THEY MAY BE
FORMED BY PLANING
IS DENOTED BY
DEFECT IS FORMED DUE TO
IMPROPER SAWING SAWING
OF TIMBER.IT IS INDICATED
BY DIAGONAL MARKS ON
SURFACE OF TIMBER
CAUSED WHEN A SMALL
DEPRESSION IS FORMED
ON A FINISHED SURFACE
OF TIMBER BY FALLING A
TIMBER OR SO
BOW:-THIS DEFECT IS
IN DIRECTION OF
LENGTH OF TIMBER
CUP:-THIS DEFECT IS
FROM ONE END
TO THE OTHER
EXTENDS FROM ONE
END TO OTHER,IT IS
KNOWN AS A SPLIT
TWIST:-WHEN A PIECE
OF TIMBER HAS
ALONG ITS LENGTH,IT IS
KNOWN AS A TWIST
TO STRESS DEVOLOPED
AND CIRCULAR CRACKS
DEVELOP IN THE
INTERIOR PORTION OF
Qualities of Good Timber
It Should have Straight Fiber
Wood Obtained from near the pith is always better than the rest of the tree.
It should be free from knots.
It should not posses natural defects.
On sawing it should give a sweet smell.
It should have regular annual rings.
It should not clot the saw teeth during sawing.
It should be Strong and heavy.
It should not split when nails are driven in to it.
It should bear high resistance shock and stresses.
It should have dark colour, give clear sound, easily workable, high
resistance to fire and free from decay.
12. On planning it should give silky texture and bright appearance.
13. It should not wrap or twist after seasoning.
14. It should respond well to polishing and painting.
Selection of Timber
7. Type of texture
8. Type of grains
9. Resistance to fire
10.Resistance to various stresses
11. Ability to retain shape
12. Easy Polishing
Seasoning of Timber
Seasoning of timber is the process of drying or
removing the moisture or Sap presents in a
freshly felled timber, under more or less controlled
Freshly felled timber contains a large humidity of
moisture roughly from 100 to 200%, based upon
dry weight of wood. If the timber is used without
seasoning it is liable to shrink , wrap and crack.
Advantages of Seasoning
Wood becomes hard, more durable, resistance
to shock and stresses produced.
Its workability is improved.
Its density is reduced, does not wrap after
Shrinkage does not occur after seasoning.
Defects like twisting, bowing and splitting do
Improved ability to polishing and painting.
Its resistance to fire is increased.
Methods of Seasoning
1. Natural Seasoning
(a) Air Drying/ seasoning
(b) Water Seasoning
2. Artificial Seasoning
(a) Kiln Seasoning
(b) Chemical Seasoning
(c) Electrical Seasoning
(a) Air Seasoning:In this method of seasoning the sawn
timber is stacked in a dry place about 30
cm above floor level with longitudinal and
crosspieces arranged one upon another,
leaving a space of a few Centimeters for
free circulation of air. Wood fit for
carpenter’s work after 2 years and for
painter’s work after 4 years.
It does not necessitate much attention
It is simple and cheap method.
Less chances of damage to the timber.
Very slow extends over years.
(ii) For large stacks considerable space is
(iii) Rigid control cannot be exercised
(iv) Block the capital a long time.
(v) Timber may get damaged by insects and fungi
during seasoning period.
(b) Water Seasoning
This method of seasoning timber
consists in keeping logs of wood completely
immersed in a running stream of water, the
longer ends of the log being kept pointing
up-stream. By this process, the sap, sugar
and gum etc are leached out of the wood and
replaced by water. The logs are then taken
out and left to dry in an open places.
It is quick process, tendency of wood to shrink
or wrap is reduced less liable to be eaten away
by worm or to decay by dry rot.
(i) The process reduces the elasticity and the
durability of the timber.
(ii) The timber is redder brittle.
2. Artificial Seasoning
(a) Kiln Seasoning:- The timber is seasoned under
controlled temperature and humidity conditions with proper
circulation and ventilation system. The rise in temperature
should be such that the timber retains the original strength
and elastic properties. The required humidity level is
maintained to avoid wrapping and cracking. The drying of
timber at uniform rate is well maintained by circulating hot
air by fans and a certain amount of steam is added in order to
retain correct humidity. The ventilation is provided to avoid
over heating and excessive humidity. The timber inside the
chamber , on trolley is kept under controlled conditions for
about fortnight or depending upon the initial water content
and required moisture level. The quality of wood is inferior as
compared to the one seasoned by natural seasoned methods.
Advantages:1. moisture content can be reduced as per requirement.
2. less time required for seasoning, less shrinkage.
3. The drying is controlled, so no chances for the attack of
fungi and insects.
4. The drying of different surfaces is even and uniform.
Disadvantages:1. It is costly.
2. More skilled labor required.
3. Due to quick seasoning so chances to check regularly
seasoning defects such as wrapping, internal cracks,
surface cracks etc.
It is also known as salt seasoning. In the method,
the timber is immersed in a solution of soluble salt. It
is then taken out and seasoned in ordinary way. The
interior surface of timber dries in advance of exterior
one and chances of formation of external cracks are
( C) Electrical Seasoning:This method of seasoning works on the principle that
heat is produced when poor conductor are placed in the
field of high frequency. The wooden planks are made to
pass through an induction coil producing high frequency.
Due to an induction effect moisture contents in the wood
is dried quickly. This method of drying is employed in
plywood manufacturing process. This method is not
popular because of prohibitive cost, lack of control
moisture content, sudden drying damage wooden fibers.
A rtificial seasoning of timber-1.mp4
A rtificial seasoning of timber.mp4
Timber Tress of India
Wood Based Products
(i) Block Board
(ii) Batton Board
(iii) Fiber Board
Plywood is made of three or more number of odd
layers, jointed together by gluing and pressing.
The central layer is called core, the outer layer is
face plys and intermediate layers as cross bands.
1. lighter weight, much stronger than solid stock
of same thickness.
2. It can be made in very large sizes.
3. Easily worked and bend into shapes of
4. Top veeners can be given fine decorative
effects to give attractive appearance.
Blockboard is a wood based panel, made up of a
core of softwood strips glued together. The strips
may be up to about 28mm wide and are placed
edge to edge and sandwiched between veneers of
softwood, hardwood or thin MDF or particleboard,
glued under high pressure.
The internal strips are generally made of light
weight poplar wood.
Blockboard is used to make doors, tables, shelves,
paneling and partition walls. It is normally used for
interior usages, due to the type of glues used. To
achieve maximum strength, it is important to ensure
that the core runs lengthways. Blockboard (also called
lumber core) has very good screw holding and can be
considered as solid wood; it has a good resistance to
Fiberboard is a type of engineered wood product that
is made out of wood fibers. Types of fiberboard (in
order of increasing density) include particle
board, medium-density fiberboard, and hardboard.
Fiberboard is sometimes used as a synonym for
particle board, but particle board usually refers to lowdensity fiberboard. Plywood is not a type of
fiberboard, as it is made of thin sheets of wood, not
wood fibers or particles. Fiberboard, particularly
medium-density fiberboard (MDF), is heavily used in
the furniture industry. For pieces that will be visible,
a veneer of wood is often glued onto fiberboard to
give it the appearance of conventional wood.
Fiberboard is also used in the auto industry to create
free-form shapes such as dashboards, rear parcel
shelves, and inner door shells. These pieces are
usually covered with a skin, foil, or fabric such as
cloth, suede, leather, or polyvinyl chloride.
A batten is a thin strip of solid material, typically made
from wood, plastic or metal. Battens are used in building
construction and various other fields as both structural and
purely cosmetic elements. In the steel industry, battens
may also be referred to as "top hats", in reference to the
profile of the metal.
In sailing, battens are long, thin strips (usually fiberglass or
some similar material nowadays, but historically wooden)
used to support the roach of a sail. They are also used
on tall ships to form the ladders up the shrouds in a
fashion similar to ratlines. They are also used to help
secure tarpaulinsover hatches, thus giving rise to the
common phrase "batten down the hatches!", meaning to
secure the hatches against an approaching storm. Used
by analogy in non-sailing contexts, it means to prepare to
weather a coming storm, whether that storm is
metaphorical or real.
In cabinetry, battens may be used to strengthen panels
Wood Working Hand Tools
Classification of tools according to their
use is given below:1. Measuring and Marking Tools
2. Holding and Supporting Tools
3. Cutting Tools
4. Planning Tools
5. Boring and Drilling Tools
6. Striking Tools
7. Miscellaneous Tools
Measuring and Marking Tools: used for
measuring, marking, setting out angles and parallel lines and
(a) Folding Rule
(b) Measuring Taps
(c) Try square
(d) MITRE Square
(e) Bevel square
(f) Marking Knife or Scriber
(g) Marking Gauge
(f) Mortise Gauge
(e) Cutting Gauge
(a) Folding Rule
(b) Measuring Steel Tap
Try Square: -used for measuring and setting out
dimensions, testing the finish of a planed surfaces, draw
parallel lines at right angles (900 ) to plane surfaces, draw
mutually perpendicular lines over a plane surface and test
the squareness to two adjacent surfaces. It consists of a
steel Blade fitting into a wooden or metallic stock at right
angle to it.
Mitre Square: measuse aand mark angle at 450
Bevel Sqaure :- measure 0 to 180 degree angle.
Marking tool: Marking Knife or Scriber: It has sharp conical edges
used to mark on even hard surfaces. The front edge is
hardened so as to resist wear and tear. It is made up of
carbon steel. It is used for measuring and marking the
points and lines on wooden stock before processing.
Marking Gauge: It is used to draw parallel lines.
The movable portion of the gauge is adjustable to suitable
position and is tightened on the stem. The piece which slides
is called stock and scribing pin is fixed on the stem.
It is used to draw two parallel
lines. Its working is similar to marking gauge except it
has two sharp edges. One fixed and second
Holding and Supporting Tools
Carpenter’s bench and bench Hook
2. Carpenter’s Vice
3. Bar or T- Clamp and C-Clamp
4. Hand Screw
Carpenter’s bench and bench Hook:- It
is table of rigid construction made of hard wood about 180cmx
120cmx90cm(H) size. Four carpenter vice are fitted on opposite
sides of bench to hold the jobs during operation.
Carpenter’s Vice: it is mostly used for holding and
supporting wooden piece. Its one jaw is fixed to the side of the table while
the other is kept movable means of screw and handle.
Clamps and screws: These are used by
carpenters for holding and supporting wood pieces in position for
carrying out different operations.
Cutting tools may classified as follows:-
Saws:-Sawing means cutting woods along the grains. The main
parts of a saw are blade and handle. The size of a saw is the
length of the blade in mm. the tooth is specified by its pitch and the
angle. The teeth are bent slightly by its pitch and the angle.
Common type of Saws :1. Rip saw
2. Cross-cut saw
3. Panel saw
4. Tenon saw (or back saw)
5. Dovetail saw
6. Compass or turning saw
7. Keyhole saw
Chisels:- In the wood work a large number of chisels
are used for cutting the wood in different manners to
produce desired shapes and verities.
Bevelled edge firmer chisel
(ii) Socket chisel
(iii) Gauge chisel
Axes:- is a cutting tool made of carbon steel. The
cutting edge is formed by beveling both sides of the
axe. It is employed for splitting wood along the grains
for rough work.
Planning Tools:- The planning tools are used for shaving or
smoothing plane surfaces. A plane may be described as a
chisel fastened to a metallic or wooden block called body.
The Chisel fastened to the body at an angle of 25 to 35
degree respectively. Another Blade called Cap Iron is used
for stiffening the cutting blade, prevents chattering and helps
in cutting and curling of shavings. The Cap iron should be
1.5mm above the cutting edge.
Wooden Jack Plane
2. Iron Jack Plane
3. Smoothing Plane
Boring and Drilling Tools:- for producing
holes in wood.
Brace and Bits
Half laps (T-lap Joint)
Left to right: Half lap, mitred half lap, cross lap and
Half lap joints are used extensively in traditional timber
framing, construction and cabinetry for framing. They
are quick and easy to make and provide reasonable
strength through good long grain to long grain gluing
surface. The shoulders provide some resistance to
racking (diagonal distortion). They may be reinforced
with dowels or mechanical fasteners to resist twisting.
Frame assembly in cabinet making
Some applications in timber frame construction
Half laps (T-lap
Cross Lap Joint
End Lap Joint
Also known simply as a 'pull lap', it is the basic form of
the lap joint and is used when joining members end to
end either parallel or at right angles. When the joint
forms a corner, as in a rectangular frame, the joint is
often called a corner lap. This is the most common
form of end lap and is used most in framing.
For a half lap in which the members are parallel, the
joint may be known as a half lap splice. This is
a splice joint and is an alternative to scarfing when
joining shorter members end to end.
Both members in an end lap have one shoulder and
one cheek each.
Internal cabinet frames
Visible frames when the frame members are to be
The main difference between this and the basic half
lap is that the joint occurs in the middle of one or both
members, rather than at the end. The two members
are at right angles to each other and one member
may terminate at the joint, or it may carry on beyond
it. When one of the members terminates at the shin ,
it is often referred to as a Tee lap or middle lap. In a
cross lap where both members continue beyond the
joint, each member has two shoulders and one cheek.
For a Tee lap, one of the members has only one
Internal cabinet frames
Simple framing and bracing
This is a lap in which the housing has been cut at
an angle which resists withdrawal of the stem
from the cross-piece.
Framing applications where tension forces could
pull the joint apart
Mitre half lap
This is a variation of the end lap which shows
a mitre on the face of the finished work.
The mitred half lap is the weakest version of the
joint because of the reduced gluing surface.
Visible framing applications where a mitre corner
mortise and tenon joint
The mortise and tenon joint has been used for
thousands of years by woodworkers around the world
to join pieces of wood, mainly when the adjoining
pieces connect at an angle of 90°. In its basic form it
is both simple and strong. Although there are many
joint variations, the basic mortise and tenon
comprises two components: the mortise hole and the
tenon. The tenon, formed on the end of a member
generally referred to as a rail, is inserted into a square
or rectangular hole cut into the corresponding
member. The tenon is cut to fit the mortise hole
exactly and usually has shoulders that seat when the
joint fully enters the mortise hole. The joint may be
glued, pinned, or wedged to lock it in place.
Timber is the wood suitable for building or
engineering purposes and it is applied to trees
measuring not less than 0.5 m in girth.
2. A good timber should have a uniform colour,
smell sweet, be sonorous when struck, have
straight and closed fibers, be heavy in weight,
and be free from flaws etc.
3. The tress may be exogenous or
endogenous. The trees should be felled when
they have just matured or when they are very
near to maturity.
4. The most common defects in timber are :
Heart shakes, star shakes, cup shakes, radial
shakes, rind galls, upset, twisted fibers, burns,
wind cracks, knots, honeycombing, end splits,
5. Seasoning of timber is the process of drying
timber or removing moister or sap, present in a
freshly felled timber, under more or less controlled
6. Seasoning of timber decreases the weight of
timber, improves its working qualities, enables it
to be easily painted, polished and preserved and
provides its dimensional stability.
7. Seasoning of timber may be carried outin following two ways:
(i) Natural Seasoning
(a) Air Drying/ Seasoning
(b) Water Seasoning
(ii) Artificial Seasoning
(a) Kiln Seasoning (b) Chemical Seasoning (c) Electrical
8. Decay of timber may be caused by :
Moister, imperfect seasoning, alternation of dry and wet states,
vegetable growth, attacks of insects etc, bad storage or stacking
of timber etc.
9. Diseases of wood are :
Dry Rot: It is decomposition of felled timber by the action of
various fungi which feed upon the wood and reduce it to a dry
10. The different methods of preservation of
timber are : Tarring, charring, painting, creasoting,
Ascue treatment, fire proofing and Abel’s process.
11. Veneers are the thin sheets or slices of wood of
superior quality, having thickiness varying from
0.4mm to 6 mm or more.
12. Plywood is made by cementing together several
layers of wood which may be thin veneers or
13. Wood working tools are classified as
Measuring and marking tools, holding and
supporting tools, cutting tools, Planning tools, Boring
and Drilling Tools, Striking tools, Miscellaneous tools.
14. Wood working processes:
Marking and laying out, Sawing, Planning, Mortising
and Tenoning, Boring, Grooving and tongueing,
Moulding, Rebatting, Recessing.
15. Classification of Joints:
Lap Joints, Dowel Joint, Grooved Joint , Miter Joint,
Mortise and Tenon Joint, Dovetail joints etc.