CARPENTRY SHOP
1. Introduction
Carpentry is the process of shaping Timber, using hand tools. The products
produced are used in building construction, such as doors and windows, furniture
manufacturing, patterns for molding in foundries, etc. Carpentry work mainly involves
the joining together of wooden pieces and finishing the surfaces after shaping them.
Hence, the term joining is also used commonly for carpentry. A student studying the
fundamentals of wood working has to know about timber and other carpentry materials,
wood working tools, carpentry operations and the method of making common types of
joints.
Wood obtained from tree is the chief product of forest. It has been universally
acceptable as raw material for manufacturing wooden products or appliances. From the
pre-historic times, wood has been utilized an important source of getting heat by firing it.
It has been utilized as an major construction material for making shelter for the basic
need of human being. As the civilization advanced, it gained tremendous importance as
special material for boatbuilding, for piling to support docks and railroad tracks. But in
modern times, with the advance of wood chemistry, the uses of wood have recognized
its importance in manufacturing cheap useful products used in day today life such as
paper, furniture, textiles, plastics and hundreds of chemicals and extractives. The
wooden products as plywood have superseded in some products in comparison metallic
and ceramic materials. Compressed wood has also replaced some metals for gears and
die casts. In war-time, in Europe, wood has been used as a source of wood gas for
propelling automobiles. Similarly clothing has-been made from wood cotton and wood
wool. The useful work on wood is being generally carried out in a most common shop
known as carpentry shop. The work performed in carpentry shops comprises of cutting,
shaping and fastening wood and other materials together to produce the products of
woods. Therefore, carpentry shop deals with the timber, various types of tools and the
art of joinery. In wood, there are two types of cells namely radiating outward from the
center of wood cross-section and running parallel to the length of wood. Trees are
generally classified into exogenous and endogenous types according to manner of
growth.
Exogenous types are also known as outward growing trees which produce timber for
commercial use. They grow outward and the additional growth which occurs each year
takes place on the outside of the trunk just underneath its bark, while the innermost
timber continues to mature. Each time the growth cycle is completed the tree gains one
more growth ring or annual ring. In counting these rings, the age of a tree can be
determined, as each ring represents one year of growth.
Endogenous trees are also known as inward growing. They grow inwards i.e.; every
fresh layer of sapwood is added inside instead of outside. Cane, bamboo and coconut
are examples of such endogenous trees. Timber is a common name imparted to wood
suitable for engineering, construction and building purposes. Timber is obtained from
trees by cutting the main body of tree in the suitable sizes after the full growth of tree.
Page | 1
,The timber structure is consisting of annual rings, heartwood, sapwood, pith, cambium
layer, bast, medullary rays and bark. Commercial timbers are commonly classified into
hardwoods and softwoods. Hardwoods comprises of oak and beech that have a broad
leaf. Whereas softwoods include pine and spruce which have narrow needle like leaf.
2. Materials Used in Carpentry:
Basic materials used in carpentry shop are timber and plywood. Auxiliary materials used
are nails, screws, adhesives, paints, varnishes, etc.
2.1. Timber:
Timber is the name given to wood obtained from exogenous (outward growing) trees. In
these trees, the growth is outward from the center, by adding almost concentric layers
of fresh wood every year known as annual rings. After the full growth, these trees are
cut and sawed to convert into rectangular sections of various sizes for engineering
purposes.
Timber is available in market in various shapes and size. The common shapes and
sizes an: given below:
Log: This is the trunk of die tree which is tree from branches.
Balk: This is the log after sawing roughly to square cross section.
Deal: This is the log after sawing into rectangular cross section of width about 225 mm
and thickness up to 100 mm.
Plank: This is the timber piece having width more than 275 mm and thickness 50 lo 150
mm.
Board: This is the timber piece below 50 mm in thickness and above 125 mm in width,
Batten: This is the timber piece below 175 mm in width and thickness between 30 mm
to 50 mm in thickness.
Scantlings: These are timber pieces of various assorted and nonstandard sizes other
than the types given above.
3. DEFECTS IN TIMBER
Defects in timber may be broadly classified into three major categories
Due to abnormal growth of trees
Due to conversion or seasoning and 3
Due to fungi and insects.
The defects in each category are described as under.
Page | 2
, 3.1. Defects Due to Abnormal Growth of Trees
Defects due to abnormal growth of trees are natural in nature and they are knots,
stakes, twisted fiber and rind galls.
Knots are too much frequent in many trees. They break the continuity of fiber and
weaken the timber. These defects may of dead or live kind. Figure given below shows a
knot defect. A dead knot will come out of the wooden piece leaving a knot hole. It is
produced when a branch is broken off before the tree has finished growing. A live knot
occurs when a branch separates from the tree after felling of the tree. Live knot will not
become loose and fall out of its position but may tend to crack. This provides inlets for
any fungi to attack the wood. If these knots are not too large and not too near the edge
of the plank, they will not present a great problem however dead knots in timber makes
the wood unsuitable for structural use.
Shakes in timber are splits in the grain and often arise as a result of uneven seasoning.
They may be of radial, heart, star, cup and upset kind. An upset or rupture is a shake in
which the fracture occurs across the grain. This is thought to be caused by violet jarring
of the timber during felling and is often found in mahogany.
Sometimes, the fibers of a tree may get twisted due to wind action in branches. This
defect is known as twisted fibers defect in timber. The fibers of wood have different
inclinations with its axis. They are no more parallel to the axis of the wood. Twisted
fibers in timber offer difficulty in working and a smooth surface cannot be obtained.
Rind gall is the defects due to abnormal growth of trees. It is the wound created on the
tree while a branch breaks and parts off or gets cut. Decay may occur at that point.
3.2. Defects Due to Conversion and Seasoning
Defects due to conversion and seasoning of timber involve shakes, warping, bowing,
twist, diamonding, casehardening and honey combing. Some of such important defects
are discussed as under.
Warping is a kind of variation from a true or plain surface and may include a one or
combination of cup, bow, crook and twist. Warping board which is tangentially sawn
may invariably warp. This takes the form of a hollowing or cupping across the face of
the board and when wide flat boards are required this will act as a serious drawback.
Wind or twist defect occurs when thin boards are cut from a log having curved
longitudinal grain. This tendency is for the board distort spirally.
Diamonding in timber is the tendency of square cut pieces to become diamond shaped
when cut from certain areas of the log. This happens when the piece has been cut with
Page | 3
1. Introduction
Carpentry is the process of shaping Timber, using hand tools. The products
produced are used in building construction, such as doors and windows, furniture
manufacturing, patterns for molding in foundries, etc. Carpentry work mainly involves
the joining together of wooden pieces and finishing the surfaces after shaping them.
Hence, the term joining is also used commonly for carpentry. A student studying the
fundamentals of wood working has to know about timber and other carpentry materials,
wood working tools, carpentry operations and the method of making common types of
joints.
Wood obtained from tree is the chief product of forest. It has been universally
acceptable as raw material for manufacturing wooden products or appliances. From the
pre-historic times, wood has been utilized an important source of getting heat by firing it.
It has been utilized as an major construction material for making shelter for the basic
need of human being. As the civilization advanced, it gained tremendous importance as
special material for boatbuilding, for piling to support docks and railroad tracks. But in
modern times, with the advance of wood chemistry, the uses of wood have recognized
its importance in manufacturing cheap useful products used in day today life such as
paper, furniture, textiles, plastics and hundreds of chemicals and extractives. The
wooden products as plywood have superseded in some products in comparison metallic
and ceramic materials. Compressed wood has also replaced some metals for gears and
die casts. In war-time, in Europe, wood has been used as a source of wood gas for
propelling automobiles. Similarly clothing has-been made from wood cotton and wood
wool. The useful work on wood is being generally carried out in a most common shop
known as carpentry shop. The work performed in carpentry shops comprises of cutting,
shaping and fastening wood and other materials together to produce the products of
woods. Therefore, carpentry shop deals with the timber, various types of tools and the
art of joinery. In wood, there are two types of cells namely radiating outward from the
center of wood cross-section and running parallel to the length of wood. Trees are
generally classified into exogenous and endogenous types according to manner of
growth.
Exogenous types are also known as outward growing trees which produce timber for
commercial use. They grow outward and the additional growth which occurs each year
takes place on the outside of the trunk just underneath its bark, while the innermost
timber continues to mature. Each time the growth cycle is completed the tree gains one
more growth ring or annual ring. In counting these rings, the age of a tree can be
determined, as each ring represents one year of growth.
Endogenous trees are also known as inward growing. They grow inwards i.e.; every
fresh layer of sapwood is added inside instead of outside. Cane, bamboo and coconut
are examples of such endogenous trees. Timber is a common name imparted to wood
suitable for engineering, construction and building purposes. Timber is obtained from
trees by cutting the main body of tree in the suitable sizes after the full growth of tree.
Page | 1
,The timber structure is consisting of annual rings, heartwood, sapwood, pith, cambium
layer, bast, medullary rays and bark. Commercial timbers are commonly classified into
hardwoods and softwoods. Hardwoods comprises of oak and beech that have a broad
leaf. Whereas softwoods include pine and spruce which have narrow needle like leaf.
2. Materials Used in Carpentry:
Basic materials used in carpentry shop are timber and plywood. Auxiliary materials used
are nails, screws, adhesives, paints, varnishes, etc.
2.1. Timber:
Timber is the name given to wood obtained from exogenous (outward growing) trees. In
these trees, the growth is outward from the center, by adding almost concentric layers
of fresh wood every year known as annual rings. After the full growth, these trees are
cut and sawed to convert into rectangular sections of various sizes for engineering
purposes.
Timber is available in market in various shapes and size. The common shapes and
sizes an: given below:
Log: This is the trunk of die tree which is tree from branches.
Balk: This is the log after sawing roughly to square cross section.
Deal: This is the log after sawing into rectangular cross section of width about 225 mm
and thickness up to 100 mm.
Plank: This is the timber piece having width more than 275 mm and thickness 50 lo 150
mm.
Board: This is the timber piece below 50 mm in thickness and above 125 mm in width,
Batten: This is the timber piece below 175 mm in width and thickness between 30 mm
to 50 mm in thickness.
Scantlings: These are timber pieces of various assorted and nonstandard sizes other
than the types given above.
3. DEFECTS IN TIMBER
Defects in timber may be broadly classified into three major categories
Due to abnormal growth of trees
Due to conversion or seasoning and 3
Due to fungi and insects.
The defects in each category are described as under.
Page | 2
, 3.1. Defects Due to Abnormal Growth of Trees
Defects due to abnormal growth of trees are natural in nature and they are knots,
stakes, twisted fiber and rind galls.
Knots are too much frequent in many trees. They break the continuity of fiber and
weaken the timber. These defects may of dead or live kind. Figure given below shows a
knot defect. A dead knot will come out of the wooden piece leaving a knot hole. It is
produced when a branch is broken off before the tree has finished growing. A live knot
occurs when a branch separates from the tree after felling of the tree. Live knot will not
become loose and fall out of its position but may tend to crack. This provides inlets for
any fungi to attack the wood. If these knots are not too large and not too near the edge
of the plank, they will not present a great problem however dead knots in timber makes
the wood unsuitable for structural use.
Shakes in timber are splits in the grain and often arise as a result of uneven seasoning.
They may be of radial, heart, star, cup and upset kind. An upset or rupture is a shake in
which the fracture occurs across the grain. This is thought to be caused by violet jarring
of the timber during felling and is often found in mahogany.
Sometimes, the fibers of a tree may get twisted due to wind action in branches. This
defect is known as twisted fibers defect in timber. The fibers of wood have different
inclinations with its axis. They are no more parallel to the axis of the wood. Twisted
fibers in timber offer difficulty in working and a smooth surface cannot be obtained.
Rind gall is the defects due to abnormal growth of trees. It is the wound created on the
tree while a branch breaks and parts off or gets cut. Decay may occur at that point.
3.2. Defects Due to Conversion and Seasoning
Defects due to conversion and seasoning of timber involve shakes, warping, bowing,
twist, diamonding, casehardening and honey combing. Some of such important defects
are discussed as under.
Warping is a kind of variation from a true or plain surface and may include a one or
combination of cup, bow, crook and twist. Warping board which is tangentially sawn
may invariably warp. This takes the form of a hollowing or cupping across the face of
the board and when wide flat boards are required this will act as a serious drawback.
Wind or twist defect occurs when thin boards are cut from a log having curved
longitudinal grain. This tendency is for the board distort spirally.
Diamonding in timber is the tendency of square cut pieces to become diamond shaped
when cut from certain areas of the log. This happens when the piece has been cut with
Page | 3
