This manual covers all aspects to be taught to first year students at the department of Engineering science and technology-SUA in the course AE 110 (CARPENTRY)

1.
SOKOINE UNIVERSITY OF AGRICULTURE
FACULTY OF AGRICULTURE
DEPARTMENT OF AGRICULTURAL ENGINEERING AND
LAND PLANNING
WORKSHOP TECHNOLOGY MANUAL
Carpentry and Joinery
Prepared by:
F. C. Kahimba
March, 2010

2. i
CARPENTRY AND JOINERY

3. ii
Table of Contents
INTRODUCTION ...................................................................................................................................................1
LEARNING OBJECTIVE ..........................................................................................................................................1
CARPENTRY AND JOINERY WORKSHOP COURSE PLAN .......................................................................................2
LESSON 1: CARPENTRY HAND TOOLS AND EQUIPMENT ..............................................................................3
1.1 Care and Maintenance of Hand Tools .................................................................................................3
1.1.1 Types of hand tools ......................................................................................................................3
1.1.2 Maintaining hand tools ...............................................................................................................5
1.2 Workshop Safety Rules and Regulations .............................................................................................6
1.2.1 Safety rules when working with hand tools ................................................................................6
1.2.2 Safety rules when working with power operated machines and equipment ..............................7
1.3 Timber Preparations ............................................................................................................................9
1.4 Practice exercise 1: Sawing, planning, gauging to the required size ................................................ 10
LESSON 2: BASIC SKILLS IN CARPENTRY AND JOINERY .............................................................................. 11
2.1 Wood Joints ...................................................................................................................................... 11
2.1.1 Corner joints ............................................................................................................................. 11
2.1.2 Frame joints .............................................................................................................................. 12
2.1.3 Widening joints ......................................................................................................................... 12
2.1.4 Lengthening joints .................................................................................................................... 13
2.1.5 Crossing joints ........................................................................................................................... 13
2.2 Nailing and Screwing ........................................................................................................................ 14
2.2.1 Commonly used nails ................................................................................................................ 14
2.2.2 Commonly used screws ............................................................................................................ 15
2.3 Gluing ............................................................................................................................................... 16
2.4 Practice exercise 2: Marking, cutting rivets and assembly of joints ................................................ 16
LESSON 3: WOODWORKING MACHINES .................................................................................................... 17
3.1 Surface and Thickness Planing Machine .......................................................................................... 17
3.1.1 Surface planning machine ........................................................................................................ 17
3.1.2 Thickness planing machine ....................................................................................................... 18
3.2 Other Woodworking Machines ........................................................................................................ 18
3.2.1 Combined circular saw ............................................................................................................. 19
3.2.2 Shaper (spindle molder) ............................................................................................................ 19
3.2.3 Bend saw .................................................................................................................................. 20
3.2.4 Slot boring machine .................................................................................................................. 20

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3.2.5 Teeth setting and sharpening machine .................................................................................... 21
3.2.6 Sandpapering machine ............................................................................................................. 22
3.2.7 Drilling machine ........................................................................................................................ 23
3.2.8 Other power operated woodworking machines ....................................................................... 24
3.3 A selection of Commercial Tanzanian Woods .................................................................................. 25
3.3.1 Woods for furniture and joinery ............................................................................................... 25
3.3.2 Roofing and flooring ................................................................................................................. 26
3.3.3 Curving and turnery .................................................................................................................. 27
3.3.4 Heavy construction, railways, and mining ................................................................................ 27
3.3.5 Wood treatment ....................................................................................................................... 28
3.4 Practice exercise 3: Finishing, sandpapering, and varnishing ......................................................... 29
LESSON 4: PLANNING FOR A CARPENTRY WORK ...................................................................................... 30
4.1 List of Materials and Tools Required for Making a Stool ................................................................. 30
4.2 Sketching a Work piece and Interpretation of Drawings ................................................................. 30
4.3 Preparation of Operation Procedures for Making a Stool ............................................................... 30
4.4 Practice exercise 5a: Preparation of materials for stool and assembly ........................................... 30
LESSON 5: FINISHING WORKS AND REVISION ........................................................................................... 31
5.1 Wood Finishing ................................................................................................................................. 31
5.2 Practice exercise 5b Finishing Works ............................................................................................... 31
5.3 Course Revision ................................................................................................................................ 31
5.4 Final Test .......................................................................................................................................... 31
REFERENCES ..................................................................................................................................................... 32
APPENDICES...................................................................................................................................................... 38

5. INTRODUCTION
Carpentry is the art or science of measuring, cutting, fitting, and assembling wood and other
materials to construct furniture, buildings, or other structures. Many people associate
carpenters with wood and other building materials and tools. They assume carpenters build
only homes, furniture, and other relatively small structures. This is not true. Carpenters work
not only with wood but also with metals, plastic, and other synthetic materials. The carpentry
trade includes skills required to construct buildings, bridges, docks, and carts. Work must be
accomplished in a manner that is consistent with environmental laws and regulations, and
safety.
The Carpentry and Joinery program develops knowledge of hand tools, woodworking machines,
plans reading and sketching and safe working practices and a familiarity with the materials and
procedures needed to enter related occupations.
Students will learn the safe and proper use of hand and power tools and woodworking
machines. They will also develop practical skills in wood preparations, joinery, framing,
furniture making, and finishing.
LEARNING OBJECTIVE
The Carpentry and Joinery workshop course provides knowledge to work safely with
woodworking tools, machines and equipment, construct and assemble various wood joints and
construct simple furniture. It also gives knowledge on woods that can be used for various
joinery works and construction purposes. The course is presented in five lessons. At the end of
these lessons, a student will be able to take a set of woodwork drawings and construct simple
furniture, explain the kinds and selections of woods, the classification and uses of woodworking
joints, and standards. The selection of materials for constructing wooden articles, assembling of
parts into units, and steps taken in a final inspection will also be presented.
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6. CARPENTRY AND JOINERY WORKSHOP COURSE PLAN
WEEK TOPIC TITLE JOB DESCRIPTION
1 Carpentry Hand Tools and Equipment
• Grouping of hand tools
• Discussion on safety rules for tools and power
operated machinery
• Cutting and planning work piece for exercise
1
• Marking, ripping, gauging and checking
square
1.1
1.2
1.3
1.4
Care and maintenance of hand tools
Workshop safety
Timber preparations
Practice exercise 1
2 Basic Skills in Carpentry and Joinery
• Discussing various types of wood joints
• Nailing, screwing and glue discussion
• Marking and cutting rivets
• Pre‐assembly and assembly of flower box
2.1
2.2
2.3
2.4
Wood joints
Nailing and screwing
Gluing
Practice exercise 2
3 Woodworking Machines
• Care, safety, and use of wood working
machines
• Operations of manual and power operated
carpentry machines
• Discussion on commercial woods for
furniture, joinery and other uses
• Finishing, sandpapering, and varnishing work
piece
3.1
3.2
3.3
3.4
Surface and thickness planing
Machine
Other hand and power operated
machines and equipment
A selection of commercial Tanzanian
woods
Practice exercise 3
4 Planning for Carpentry Work
• Listing tools and materials required for
preparation of stool
• Sketching of stool and interpreting work
piece drawings
• Preparing operational procedures for making
stool
• Planning, sizing and pre‐assembling members
of a stool
4.1
4.2
4.3
4.4
List of materials
Sketch of work piece
Operation Procedures
Practice exercise 4
5 Finishing Works and Revision
• Final assembly, sandpapering and varnishing
stool
• Course revision
• Final Written test
5.1
5.2
5.3
Finishing works
Course revision
Final test
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7. LESSON 1: CARPENTRY HAND TOOLS AND EQUIPMENT
1.1 Care and Maintenance of Hand Tools
1.1.1 Types of hand tools
There are various types of hand tools that are used in carpentry and joinery. They can be
categorized into cutting, planning, measuring, bracing, chiseling, drilling, and hammering tools.
Example of the carpentry tools are folding rule, measuring tapes, carpenter’s pencil, claw
hammer, nail punch, combination square, steel square, wall board saw, coping saw, sliding
bevel, set of chisels, screwdrivers, spirit level, wrecking bar, plumb bob, end cutting nippers,
adjustable spanner, pliers, tin snips, hacksaw and blades, chalk line, string line, sanding block,
cutting knife, cramp or clamp, straight edge, socket set, pop riveter;
Cutting tools are such as back saw, rip saw, tenon saw, dovetail saw, and frame saw. Tenon
saws are used primarily for making small cuts in wood and cutting tenons when jointing. They
have generously deep, high quality alloy steel blades, which have excellent edge holding
properties. Rip saws are used for cutting mainly along the grains. Frame saws are used mainly
for straight and circular cuts.
Fig. 1.1a Rip saw Fig. 1.a Tenon saw
Fig. 1.1c Frame saw Fig. 1.1d Dovetail saw
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8. The frame saw has the following parts: 1) saw blade, 2) saw knobs, 3) saw arms, 4) stretcher,
and 5) tensioning device. Frame saws are applicable for nearly all processes in manual
woodworking.
Measuring tools: In manual woodworking it is necessary to measure lengths, widths and
thicknesses as well as bevels (angles) of workpieces. Common instruments for measurements
are folding rule 1‐2 m (Fig. 1.2a), steel rule, measuring tape, and carpentry square. In case of
often appearing sizes fixed length gauges and angle gauges are used for scribing and checking.
Gauges represent only special sizes.
Hammering tools: common hammering tools used are claw hammer and mallet (wooden
hammer). A mallet is normally used for hammering on surface of wood directly without
destroying the surface. The claw hammer is used for driving nails in and out of wood, and for
other general hammering purposes.
Fig. 1.2a Folding rule Fig. 1.2b Carpentry plane
Fig. 1.2c Hand drill Fig. 1.2d Carpentry brace
Hand tools used for drilling holes in wood are such as hand brace (carpentry brace), hand drill
(Fig. 1.2c), and manual hand screws.
A carpentry work bench (Fig. 1.3) provides a platform for working with hand tools. It may
contain built‐in braces to hold a work piece while working on it. The work bench can also be
used to store some of the tools underneath. It is important to keep the workbench clean
before, during, and after working to ensure safety of the worker and tools.
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9.
Fig. 1.3 Carpentry work bench
1.1.2 Maintaining hand tools
Proper maintenance of hand tools is essential to ensure that the tools last longer and do not
cause injury. The following rules should be observed to ensure hand tools are handled properly:
• Tools are selected to meet identified job requirements.
• Tools are used in accordance with manufacturer’s recommendations and/or work site
practice.
• Tools are used to complete the operation without injury to the user or bystanders, or
damage to materials
• Cutting edges are ground and sharpened to give maximum cutting efficiency.
• Tools are maintained in working order, clean and free of rust.
• Damaged or broken tools are either repaired or replaced in accordance with work site
practice.
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10. 1.2 Workshop Safety Rules and Regulations
1.2.1 Safety rules when working with hand tools
Workshop tools and equipment can cause injury if proper safety rules are not followed. The
following are safety procedures to be followed when working with hand tools:
• Select the right tool for the job. Substitutes increase the chance of having an accident.
• Use tools designed to allow wrist to stay straight. Avoid using hand tools with your wrist
bent.
• Use good quality tools.
• Keep tools in good condition at all times.
• Inspect tools for defects before use. Replace or repair defective tools.
• Keep cutting tools sharp and cover sharp edges with suitable covering to protect the
tool and to prevent injuries from unintended contact. .
• Replace cracked, splintered, or broken handles on files, hammers, screwdrivers, or
sledges.
• Ensure that the handles of tools like hammers and axes fit tightly into the head of the
tool.
• Replace worn jaws on wrenches, pipe tools and pliers.
• Redress burred or mushroomed heads of striking tools.
• Pull on a wrench or pliers. Never push unless you hold the tool with your palm open.
• Point sharp tools (e.g., saws, chisels, knives) lying on benches away from aisles and
handles should not extend over the edge of the bench top.
• Maintain tools carefully. Keep them clean and dry, and store them properly after each
use.
• Carry tools in a sturdy tool box to and from the worksite.
• Wear safety glasses or goggles and well‐fitting gloves appropriate for the hazards to
which you may be exposed when doing various tasks.
• Keep the work environment clean and tidy to avoid clutter which may cause accidents.
The following should be avoided when working with hand tools:
• Do not use tools for jobs they are not intended to do. For example, do not use a slot
screw drivers as a chisel, pry bar, wedge or punch or wrenches as hammers.
• Do not apply excessive force or pressure on tools.
• Do not cut towards yourself when using cutting tools.
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11. • Do not hold the stock in the palm of your hand when using a cutting tool or a
screwdriver.
• Do not throw tools. Hand them, handle first, directly to other workers.
• Do not carry tools in a way that interferes with using both hands on a ladder, while
climbing on a structure, or when doing any hazardous work. If working on a ladder or
scaffold, tools should be raised and lowered using a bucket and hand line.
• Do not carry a sharp tool in your pocket.
1.2.2 Safety rules when working with power operated machines and equipment
The following are safety procedures to be followed when working with power‐operated
equipment and machinery:
• Always wear safety glasses or goggles
• Wear dust masks when required.
• Wear hearing protection that is suitable for the level and frequency of the noise you are
exposed to in the woodworking area. If you have trouble hearing someone speak from
three feet away, the noise level from the machine is too high. Damage to hearing may
occur.
• Use gloves to protect hands from splinters when handling wood but do not wear them
near rotating blades and other machinery parts where the gloves can catch.
• Make sure the guard is in position, is in good working condition, and guards the machine
adequately before operating any equipment or machine. Check and adjust all other
safety devices.
• Make sure the equipment is properly grounded before use.
• Check that keys and adjusting wrenches are removed from the machine before turning
on the power.
• Inspect stock for nails or other materials before cutting, planing, routing or carrying out
similar activities.
• Make sure that all machines have start and stop buttons within easy and convenient
reach of an operator. Start buttons should be protected so that accidental contact will
not start the machine.
• Ensure that all cutting tools and blades are clean, sharp, and in good working order so
that they will cut freely, not forced.
• Turn the power off and unplug the power cord (or lock out the power source) before
inspecting, changing, cleaning, adjusting or repairing a blade or a machine. Also turn the
power off when discussing the work.
• Use a "push stick" to push material into the cutting area. Jigs are also useful in keeping
hands safe during cutting procedures. Keep hands out of the line of the cutting blade.
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12. • Clamp down and secure all work pieces when drilling or milling.
• Use good lighting so that the work piece, cutting blades, and machine controls can be
seen clearly. Position or shade lighting sources so they do not shine in the operator's
eyes or cause any glare and reflections.
• Ensure that the floor space around the equipment is sufficient to enable you to machine
the size of work piece being processed safely without bumping into other workers or
equipment.
• Woodworking machines should be fitted with efficient and well‐maintained local
exhaust ventilation systems to remove sawdust or chips that are produced.
• Electric power cords should be above head level or in the floor in such a way that they
are not tripping hazards.
• Keep work area free of clutter, clean, well swept, and well lit. Spills should be cleaned up
immediately. Floor areas should be level and non‐slip. Good housekeeping practices and
workplace design will reduce the number of injuries and accidents from slips, trips, and
falls.
When working with power operated machines the following should be avoided:
• Do not wear loose clothing, work gloves, neckties, rings, bracelets or other jewelry that
can become entangled with moving parts.
• Avoid awkward operations and hand positions where a sudden slip could cause your
hand to move into the cutting tool or blade.
• Do not remove sawdust or cuttings from the cutting head by hand while a machine is
running. Use a stick or brush when the machine has stopped moving.
• Do not use compressed air to remove sawdust, turnings, etc. from machines or clothing.
• Do not leave machines running unattended (unless they are designed and intended to
be operated while unattended). Do not leave a machine until the power off is turned off
and the machine come to a complete stop.
• Do not try to free a stalled blade before turning the power off.
• Do not distract or startle an operator while he or she is using woodworking equipment.
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13. 1.3 Timber Preparations
Timber preparations involve preparing a work piece to the size specified in the drawings. During
timber preparations the following activities needs to be accomplished.
a) Wood selection: a wood needs to be selected based on type of work that needs to be
accomplished. Some works can be done using softwoods while others may require
hardwoods. The dimensions of the raw wood should be large enough such that
unnecessary joints are avoided.
b) Marking: The raw wood needs to be marked to the required dimensions of a work piece
with allowance for sawing and planning.
c) Sawing: if the wood size was larger than the required dimensions it has to be cut from
the raw wood to the required size of a work piece, leaving allowances for planing.
d) Planing: Once a work piece has been cut it has to be planed on one wider side to the
required straightness both longitudinally and tangentially. Then one edge is planed so as
to achieve straightness and square with respect to the wider planed side. Sometimes a
bigger raw wood can be planed and straightened before cutting a work piece to a
required size.
e) Gauging: Once two adjacent edges are straight and square with respect to each other, a
gauge is used to marc the required thickness and width of the work piece.
f) Final planning: a work piece is then planned to achieve the final dimensions with gauge
marks taken as references. If the gauge marks are far from the unfinished side of the
work piece, it can be sawed again before planning to its final dimension.
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14. 1.4 Practice exercise 1: Sawing, planning, gauging to the required size
In practical exercise 1, students will learn how to use hand tools to prepare a wood for making
sides of a flower pot. Students will perform tasks of wood preparations that involve marking,
sawing, planning and gauging a work piece. Students will prepare two workpieces each with
dimensions 250 mm long, 60 mm wide and 20 mm thick.
Fig. 1.4 Workpieces for preparation of flower box.
250 mm
60 mm
20 mm
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15. LESSON 2: BASIC SKILLS IN CARPENTRY AND JOINERY
2.1 Wood Joints
There are many ways of fastening pieces of wood together. Some are purely functional such as
butt joints, while others such as dovetails are functional as well as decorative. To add additional
strength or appeal, two or more types of joints are often combined together. Some wood joints
employ fasteners, bindings, or adhesives, while others use only wood elements. The
characteristics of wooden joints (strength, flexibility, toughness, etc), are derived from
properties of the joining materials and how they are used in the joints. Therefore, different
joinery techniques are used to meet differing requirements.
Wood joints can be grouped into the following categories: corner joints, frame joints, widening
Joints, lengthening Joints, and crossing Joints,
2.1.1 Corner joints
• Nailed joint
• Stopped rebate joint
• Screw joint – better since screws have threads that pull members together hence
making a stronger joint
• Rebate joint screwed
• Tongue and groove joint
• Finger joint
• Through dovetail joint
• Lap dovetail joint – e.g. joints used for wardrobes and drawers
.
Fig. 2.1a Tongue and groove joint Fig. 2.1b Dowel butt joint
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16. Fig. 2.2 Some selected basic types of joints
2.1.2 Frame joints
• Corner halving joints
• Open mortise and tenon frame
• Open mortise and tenon long and short shouldered – can have long and short shoulders
for frames
• Cross halving joint
• Double mortise and tenon
• Miter corner halving
• Through mortise and tenon
• Hidden mortise and tenon
• Through double mortise and tenon
2.1.3 Widening joints
These are types of joints that are used to increase the width of wood. They are mainly used for
construction of wider surfaces such as boxes, table tops, and cupboards.
• Edge to edge glued joints
• Loose tongue joints
• Fixed tongue joints
• Dowelled joints
• Dowelled or glued lap joints
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17. 2.1.4 Lengthening joints
Joints used to increase the length of wood for construction of trusses, roof structures, wood
partitioning, etc. Lengthening joints are also commonly used in temporary works such as
construction of formworks and scaffolding.
• Scarf joint
•
Fig. 2.3a Scarf joint.
• Fisher joint
Fig. 2.3b Fisher joint
2.1.5 Crossing joints
These types of joints involve crossing two or more members at or close to their centers.
Commonly used for monopole members such as lamp stand and one‐legged tables.
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18. 2.2 Nailing and Screwing
There are many different types of nails and screws. They are used primarily to hold two pieces
of timber together, or fixing a timber piece with other materials such as iron sheets,
chipboards, plywood, gypsum boards, etc. A good rule of thumb to remember is that the
thicker the material the larger the nail or screw. Also, if nailing or screwing into hardwoods or
close to the end of the material, be sure to pre‐drill the nail and screw holes first to avoid
splitting. Another basic rule of thumb (though not always possible to follow) is that two‐thirds
of the fasteners length should penetrate the lower member of the union.
2.2.1 Commonly used nails
Flat Head/Wire Nail
For rough carpentry work: large ugly head ensures a firm grip.
Liable to split wood. Blunting the point can help to avoid this.
Bullet Head/Oval Brad
Commonly used in carpentry. Oval cross section makes it unlikely
to split wood if the long axis follows the grain.
Lost Head
General carpentry nail. Head can be punched below surface and
the hole filled. Called a "finish nail" in the U.S.
Panel Pin
Small nail for securing light pieces of wood; usually used in
conjunction with glue.
Roofing nails:
Commonly used to fix corrugated iron sheets into timber
structure. Aluminum nails are used with aluminum sheets while
mild steed nails are used with normal iron sheets.
Clout
Large headed for fixing roofing felt, sash cords, wire fencing to
wood. Galvanized for outdoor work. Called a "roofing nail" in the
U.S.
Flooring Brad/Cut Nail
Used to hold down floorboards. Good holding power and unlikely
to split wood. Good fixing for lightweight insulation block.
Glazing Brad
Headless: used to hold glass into picture frames, window sashes
and liner to floorboards. Will not grip if driven too far in.
Masonry Nail
Hardened steel nail for fixing wood to soft brick, breeze block and
concrete.
Hardboard Pin
14

19.
Special head shape countersinks itself in hardboard and can be
filled over.
Upholstery Nail
Decorative head used to cover tacks in upholstery work.
2.2.2 Commonly used screws
Flat Head Screw (Counter Sunk)
Used for general woodwork. The head sinks in flush with or slightly
below the wood surface.
Cross Head/Pozi Drive Screw (Counter Sunk)
Used for general woodwork, but needs a special screwdriver which
does not slip from the head. Called a "Phillips Head" screw in the U.S.
Round Head Screw (Counter Sunk)
Used for fixing door‐handle plates and other decorative fittings with
countersunk holes. The head is designed to be seen.
Round Head Screw
Used for fixing hardware fittings without countersunk holes. The head
protrudes from the work.
Mirror Screw
Used for fixing mirrors and ' bathroom fittings. The chromed cap
threads into the screw head to hide the screw. Do not over tighten.
Nut Head/Coach Screw
Used for fixing heavy constructions together and heavy equipment to
timbers. Tighten with a spanner. Called a "lag screw" in the U.S.
Invisible Screw/Dowel Screw
Used for invisible joining of two pieces of timber.
Panel Screw
Used for fixing thin sheets of metal and plastic. Cuts its own thread as
it is screwed in. Various types of head are available.
Chip or Custom Board Screw
Used for securing chipboard and its derivatives. Various types of heads
are available.
15

20. 2.3 Gluing
Glue is a mixture in a liquid or semi‐liquid state that adheres or bonds items together.
Adhesives may come from either natural or synthetic sources. Main types of glue are water
solvent, water proof (synthetic resin), and petroleum products e.g. Patex for Formica and PVC
materials. During application of glue to a wood surface care should be taken not to apply
excessive glue that can result in spillover when wood members are tightly fixed together.
2.4 Practice exercise 2: Marking, cutting rivets and assembly of joints
In exercise 2 students will practice how to mark and cut rivets, and assembling a corner joint.
Two workpieces prepared in practical exercise 1 will be used for this exercise. One member will
be cut to form a corner halving joint. Carpentry square will be used to mark a line across the
wood member. Marking gauge will be used to mark 10 mm line along the thickness of the
wood. A tenon saw will be used to cut the tenon joint.
Members will then be joined together using nails as shown in Figure 2.3 below.
Fig. 2.4a Flower Boxes
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21. LESSON 3: WOODWORKING MACHINES
A Woodworking machine is a machine that is intended to process wood. These machines are
usually powered by electric motors and are used extensively in woodworking. Woodworking
tools and machineries can be very dangerous if not used properly. Only use woodworking
machines that you have been trained to use properly and safely and read the owner's manual
carefully. Make sure you understand instructions before attempting to use any tool or machine.
Ask questions if you have any doubts about doing the work safely. Various types of power
operated woodworking machine are discussed in the sections that follow.
3.1 Surface and Thickness Planing Machine
3.1.1 Surface planning machine
A surface planing machine is used for planing reference surface and one edge. Once the two
surfaces are planed they will be straight and square with respect to each other.
Fig. 3.1 Surface planing machine
Precautions:
• Do not plane less than 40 mm
• Very thin sheets are not allowed
• For short pieces push using safety board
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22. 3.1.2 Thickness planing machine
The thickness planning machine is used for sizing wood to get its final required thickness. Some
machines come with combined uses of both surface and thickness planning. The thickness
planning machine contains the following parts:
• Grippers – avoid backward movement of work piece
• In feed roller – to feed the work piece. It has spring compartments to allow pieces of
different thicknesses to be fed
• Pressure bar – to press work piece into the table
• Cutter holder
• Out feed roller
• Anti friction rollers – to reduce friction during planing
• Scale for adjustment of depth of cut (1 rev = 1.5 mm
• Lock gear to reduce table vibrations
• Gear to determine the length of the board to be fed 7 indicates 7 m/min
Fig. 3.2 Thickness planer machine
3.2 Other Woodworking Machines
Some woodworking machines and equipment are manual while most of the machines and
equipment are power operated. Examples of other power operated machines are given in the
sections below:
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23. 3.2.1 Combined circular saw
Fig. 3.3 Combined circular saw.
The combined circular saw is used for cutting across and along the grains of a wood. It can also
be used for cutting chipboards, plywood, and laminated sheets. The dividing wedge bends
towards or away from the saw to prevent tightening of the saw by timber. A cap prevents
splash of the chips. A circular saw can be tilted up to 45 degrees.
3.2.2 Shaper (spindle molder)
The Shaper (spindle molder) is used for different types of molding. It can be used to mold
circular members and make circular decorations on wood, e.g. legs of tables, stools, coaches,
and beds, curtain boxes, etc.
19

24.
Fig. 3.4 Spindle molder machine.
3.2.3 Bend saw
A bend saw is used for straight and curve cutting. It can be used to cut round shapes. The
blades range from 6 mm to 40 mm. For small curves use a small blade. The bend saw contains
motor driven wheel, saw driven wheel, and tension wheel.
3.2.4 Slot boring machine
The slot boring machine is used for boring holes and slots.
20

25. Fig. 3.5 Slot boring machine.
3.2.5 Teeth setting and sharpening machine
The teeth setting and sharpening machine is used for setting and sharpening saw teeth and
sharpening tools.
Fig. 3.6 Teeth setting machine
21

26.
Fig. 3.7 Tools sharpening machine.
3.2.6 Sandpapering machine
The sandpapering machine is used for sandpapering wood pieces to give a smooth surface
finish. The sandpaper belt is used for larger pieces, while a disc sander is used for smaller work
pieces. Types of sandpapers used are P60, P80, P100, P250 (numbers represent particles per
sm2
). A larger number indicates a more and finer sand particles and hence a smoother finish.
22

27.
Fig. 3.8 Sandpapering machine.
3.2.7 Drilling machine
Used for boring circular holes in a wood. It can also be used for drilling mortises and cutting
circular or other shapes at the middle of a wood piece.
Fig. 3.9 Drilling machine.
23

28. 3.2.8 Other power operated woodworking machines
Chain mortiser: for construction of mortises.
Dovetail machine: used for construction of dovetail and finger joints.
Plane knife grinder: used for sharpening plane knives.
Rod milling machine: for molding circular rods.
Vacuum cleaner: for removing dusts inside the workshop
Fig.3.10 Vacuum cleaner for vacuum cleaning inside a workshop.
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29. 3.3 A selection of Commercial Tanzanian Woods
3.3.1 Woods for furniture and joinery
a) High class furniture and joinery
• PTEROCAPUS ANGOLENSIS – (Trade name: ‐ Mninga): It is a hardwood timber used for
furniture and high class joinery, and parts of boats. It has very low shrinkage rates (12%
moisture content, 0.8% shrinkage radially, and 0.9% longitudinally). Commonly
available in Savannah and along the coast.
• CLOROPHORA EXELSA (Trade name: ‐ Mvule, Iroko): It is a hardwood timber used for
furniture and high class joinery. It is strong, durable and decorative. Shrinkage rates are
15% and 25% radial and longitudinally, respectively. Used for bridge timber, railway
wagons, boat frames, etc.
• TECTONA GRANDIS – (Trade name: ‐ Teak): Hardwood timber used for high class
furniture & joinery, ship building. Shrinkage rates are 1.5% and 2.5% radial and
tangential, respectively.
• AFZELIA QUANZENSIS – (Trade name: ‐ East African Afzelia): For furniture and Joinery.
Shrinkage rates are 0.9% and 1.2% radial and tangentially, respectively.
• Other species: Mfimbo, Mahogany.
Fig. 3.11 Samples of woods for high class furniture.
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30.
b) Furniture and general joinery
• OLEA WELWITSCH – (Trade name:‐ Loliondo): Mainly available in USA River in Arusha
• OCOTEA USAMBARENSIS – (Trade name: ‐ East African Camphor). Available in Tanga
region.
• Mtambara: Available in Iringa region and Usambara mountains.
• Mtanga: Available in southern regions.
c) Joinery
• GREVILLEA ROBUSTA (Grevillea): Mainly available in the northern mountains. Used for
buildings e.g. TNG and flooring. Shrinkage rates are 1.6% radial and 4.4% tangentially
• Other timber varieties are JUNIPERUS PROCERA (African pencil cedar), Mndandalika,
and Hagenia.
• Common timber for boxes and crates are PINUS RADIATA (Pines), and East African
Bombay
3.3.2 Roofing and flooring
a) Roofing
• PODOCAPUS GRACILLOR (Trade name: ‐ Podo): It is a standard timber for building
available in many parts of the country, especially in the northern regions of Moshi and
Arusha.
• CUPRESSUS LUSITANICA (E. A. Cypress): Available in Usambara and mainly used for low
grade building works.
26

31.
Fig. 3.12 Wood samples for general roofing works.
b) Flooring
• Baphia: Found in coastal areas. Used for heavy duty flooring, turnery, and boat building.
Very strong and durable
• Muhuhu: Found in the northern districts. Used for first class flooring in hotels and
offices.
• Pangapanga: Found in southern regions. Used for decorative flooring.
3.3.3 Curving and turnery
• DALBERGIA MELANDXYLON (African black tree, mpingo): Found in the forests and
savannah of coastal regions. Used for carvings, making musical instruments and
bearings.
• TAMARINDUS (Mkwaju): Found in dry Savannah woodlands. Used for making charcoal,
boats building, turnery, and furniture parts.
3.3.4 Heavy construction, railways, and mining
• JULBERNARDIA GLOBIFLORA (Muwa): Found in western and southern Tanzania. Used for
railway sleepers. Shrinkage rates are 2.9% radial and 3.6% tangentially.
• AFROMOSIA ANGOLENSIS (E. A. Afromosia). Found in the Savannah areas of western
and southern Tanzania. Used for mining timber, bridges, fence, railway sleepers, and
mallets.
• BURCHEA AFRICANA (Burkea): Heavy duty hardwood timber found in the Savannah
woodlands
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32. • CORDYLA AFRIANA (Cordyla): Found in swamp forests of North and East Tanzania. Used
for railway sleepers and heavy construction.
3.3.5 Wood treatment
Wood treatment is performed in order to extend its lifespan, preserve its structural integrity,
and protect its appearance. The treatment processes normally increase the durability and
resistance of the wood from being destroyed by insects or fungi. Wood treatment can either be
preservation or protection. The wood preservation involves impregnating wood with pesticides
to give it a long resistance against organisms that can cause deterioration. Wood protection
involves treating wood surfaces to prevent surface discoloration and sap stains by living
organism.
The deterioration of wood occurs when fungi and other organism attack the wood and break
down the cellular structure making the wood weak. This result into sap stains, soft rot, and
finally complete wood decay. Insects such as wood bores and termites feed on wood causing
holes and channels inside the wood. This results in internal damage of the wood hence
weakening its structural integrity.
Various chemicals are used to treat woods that are applied through vacuum and/or pressure
treatment. Examples are as explained below:
a) Chromated copper arsenate (CCA)
In CCA treatment, copper is the primary fungicide, arsenic is a secondary fungicide and an
insecticide, and chromium is a fixative which also provides ultraviolet (UV) light resistance. The
wood is pressure treated using CCA. In the pressure treatment process, an aqueous solution of
CCA is applied using a vacuum and pressure cycle, and the treated wood is then stacked to dry.
This treatment is common, recognized for the greenish tint it imparts to timber.
b) Copper azole
Copper azole preservative (denoted as CA‐B and CA‐C) is a major copper based wood
preservative that has come into wide use following restrictions on CCA. Its use is governed by
national and international standards, which determine the volume of preservative uptake
required for a specific timber end use.
c) Borate preservatives
Boric acid, oxides and salts (borates) are effective wood preservatives and are supplied under
numerous brand names throughout the world. Borate treated wood is of low toxicity to
humans, and does not contain copper or other heavy metals. However, unlike most other
preservatives, borate compounds do not become fixed in the wood and can readily be leached
out. Therefore they should not be used where they will be exposed to rain, water or ground
contact.
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33. d) Oil‐borne preservatives
These include pentachlorophenol and creosote. They are toxic, have an unpleasant odor and
are generally not used in consumer products.
e) Coal‐tar creosote
Creosote is a tar‐based preservative that has been commonly used for telephone poles and
railroad ties. Creosote is one of the oldest wood preservatives, and was originally derived from
a wood distillate. These days virtually all creosote is manufactured from the distillation of coal
tar. It often collects inside chimneys and may cause a fire hazard. Creosote is regulated as a
pesticide and is not usually sold to the general public. It is still used for railroad ties (railway
sleepers and cross ties) and utility poles.
3.4 Practice exercise 3: Finishing, sandpapering, and varnishing
In this exercise students will perform practical work of Finishing, sandpapering and varnishing a
work piece that assembled in the previous exercise. The sandpapering will be done manually
using a piece of sand paper and wood. Then after attaining the required smooth finish student
will fill gaps in the joints of the work piece using appropriate filler, do the second sand papering
and finally applying two coats of varnish.
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34. LESSON 4: PLANNING FOR A CARPENTRY WORK
4.1 List of Materials and Tools Required for Making a Stool
For a carpentry work to be accomplished it requires and understanding of materials required to
accomplish the work and the required tools. In lesson 4 students will be making a stool. Hence a
student will be required to list all the materials required for making a stool. The student will
also prepare a list of tools required to accomplish the task and their expected use.
4.2 Sketching a Work piece and Interpretation of Drawings
Sketching and interpretation of carpentry drawings is an important knowledge in carpentry.
Students are supposed to make sketches of various parts of the work piece (stool) with proper
dimensioning. They will also need to prepare the plans, elevations and projection of the work
piece before starting to fabricate it.
4.3 Preparation of Operation Procedures for Making a Stool
Students will be required to write step by step procedures required to accomplish the tack of
making furniture (stool). The procedure will describe the preliminary preparations required,
markings and gauging, sawing, planing, assembling, and finishing.
4.4 Practice exercise 5a: Preparation of materials for stool and assembly
In this exercise students will be required to make a stool. Students can work independently if
time allows or in a group of two. The students will do the marking, sawing, planing, drilling,
cutting tenons, pre‐assembling and assembling a stool. At the end of the exercise students
should have gained knowledge on how to make simple carpentry furniture.
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35. LESSON 5: FINISHING WORKS AND REVISION
5.1 Wood Finishing
Wood finishing is the process of polishing and/or protecting the surface of a wooden material.
The process starts with surface preparation, either by planning, scraping or sanding by hand
using a sanding block or power sander. Imperfections or nail holes on the surface may be filled
using wood putty or pores may be filled using wood filler.
The first procedure of a good finish starts with surface preparation. Sand, scrape, or plane the
surface until the surface is free of defects and uniform. The amount of sanding and the grit of
sandpaper used can have a significant impact upon the way "stain" will appear on a wood
surface. The wood surface should be evenly sanded to a 150 or 220 grit uniform surface. Take
care to remove all glue marks and scratches, common stains will highlight these defects. If you
have not done much staining you should experiment before applying any stain to your project
When applying the wood finish to the surface of wood, a number of coats of finish may be
applied, often sanding between coats. Commonly used wood finishes include varnish, wax,
shellac, drying oils (such as linseed oil or Tung oil), lacquer, or paint.
5.2 Practice exercise 5b Finishing Works
In this exercise students will apply the theoretical knowledge they have gained on finishing
works and perform practical work of finishing, sandpapering and varnishing a work piece that
was assembled in the exercise 5a. The sandpapering will be done manually using a piece of
sand paper and wood. Then after attaining the required smooth finish student will fill gaps in
the joints of the work piece using appropriate filler, do the second sand papering and finally
applying two coats of varnish.
5.3 Course Revision
The instructor will revise with students major topics that were covered in the course and probe
students to ask questions on areas that needs clarification.
5.4 Final Test
The final test will be a written and closed book test covering all the knowledge gained in both
theory and the practical sessions. The final grading for the course continuous assessment will
combine the marks awarded on practical exercises and the final written test.
31

36. REFERENCES
1. Riley, M. and Cotgrave, A. 2004. Construction Technology 2: Industrial and Commercial
Building, 1st
Edition. Palgrave Macmillan. ISBN 0‐333‐80482‐1.
2. Sawdust making. About Joints.
http://www.sawdustmaking.com/About%20Joints/about_joints.htm
3. Safe use of work equipment. Provision and Use of Work Equipment Regulations 1998.
Approved Code of Practice and guidance L22 HSE Books 1998. ISBN 0 7176 1626 6
4. Safe use of woodworking machinery. Provision and Use of Work Equipment Regulations
1998 as applied to woodworking machinery. Approved Code of Practice and guidance
L114 HSE Books 1998 ISBN 0 7176 1630 4
5. Miller, M., R. Miller, and G. Baker. 2004. Carpentry and Construction. 4th Edition.
McGraw‐Hill Professional, Columbus, Ohio.
6. Darbyshire, D. T. 1988. Technical Drawing and Elements of Design. Longmans, Canada.
7.
32

37. APPENDICES
Appendix 1a: Samples of wood used for making boxes and crates
33

38. Appendix 1b: Samples of wood used for making furniture and general joinery
34

39. Appendix 2: Workbench with wood guide for cutting tenons
35