Carpentry and joinery module 4 notes PDF

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NCA AR01 – 12 Building materials and construction. Reference book: Building construction and materials by Gurcharan Singh Building construction by B.C.Punmia

Module II

: Carpentry and joinery

Carpentry and joinery Timber to be used for structural construction such as door frames window and trusses etc. Carpentry is a term applied to that form of wood construction which has to resist stress due to loads coming on it. The term joinery may be defined as the trade in wood work in which skilled labour is required to render the wooden members capable of framing together. In india carpentry & joinery are treated as a single trade.The word carpentry is used to indicate both carpentry and joinery. And the workman who handles the work of carpentry & joinery is called carpenter.

Technical terms in carpentry The following technical terms are commonly used in carpentry. 1. Sawing : It is the art of cutting wood by means of a saw. 2. Shooting : it is a art of dressing of edges of a timber pieces so as to make them straight and square with the face. 3. Chamfering : It consist of taking off the edges or corner or arras of a wooden member. The chambered member has a sloping edge which ussualy has a slope of 45*. If tha angle is other than 45*, it is know as bevel. 4. Planing : It is a process of taking the shaving off wood, with the help of a tool known as planner. Due to this timber surfaces are made smooth. Planed or smoothened surface is known as dressed or wrought surface. 5. Mitring and Scribing. Mitring is the process of joining two wooden membera at an angle. If one end of the molding is cut to suit the profile of another moulding it is known as Scribing. 6. Moulding is a process of shaping various units of construcrion either by hand or by machine to produce moulded section. [Type text]

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7. Rebating : It is the process of cutting a rectangular groove on the edge of timber so as to enable the edge of another timber piece to fit in the former. 8. Housing : It is the process of sinking of edge of one piece of timber into one another by cutting groove across its grains. 9. Nosing : is the egde of portion over hanging a vertical surface 10. Batten: is a narrow strip of wood which is nailed over joints of boards 11. Veneering: is the process of covering of entire exposed surface of timber 12. Studding: is a term applied to fixing of small timber battens to timber wall to which lathes and boards are to be nailed. 13. Bead : is rounded or semi- circular moulding provided on the edges or surface

Principles Governing The Construction Of Joints Joints play the most important role in timber construction since they provide structural stability, improve aesthetic appearance and facilitate the construction. However joints are the weekest parts of a timber structure. Hence the following principles can be followed. 1.The joints should be cut and placed in a such a way that it weakens the connecting members to the minimum. 2.Each abutting surface of joint should be as far as possible, normal to the line of pressure coming upon the joints 3.Each abutting surface of a joint should be designed for maximum compressive stress likely to coming upon the joint. 4. Surface of a joint should be formed and fitted accurately so that there is a even distribution of pressure. 5. the fastenings should be proportioned in a such a way that they possess equal strength in relation to the members which they connect. 6. the fastenings should be placed and designed in a such a manner as to avoid failure of joint by shear or crushing. 7.The joint should be simple as far as possible. Complicated joints are difficult to construct.

Carpentry Joints  Traditional timber joints  Non traditional timber joints [Type text]

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Classification of joints Various types of joints used in wood work may be classified into :  Lengthening Joint  Widening Joint  Bearing Joint  Framing Joint  Angle or Corner Joint  Oblique Shoulder Joint

LENGTHENING JOINT These are also known as spliced or longitudinal joints. These joints are used to increase the length of the wooden members such as ties, strut, etc It is further classified into :  LAPPED JOINTS  FISHED JOINTS  SCARFED OR SPLICED JOINTS  TABLED JOINT

LAPPED JOINTS This is the simplest type of joint, formed by placing the 2 ends of the member on over the other for a short distance and binding them together by means of wrought iron staps and bolds. If the member carries tensile strength , it is essential to provide bolts passing through both the pieces. Strap and bolts Mild steel

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FISHED JOINTS In this joint the end of the 2 members are cut square and placed touching each other. They are then joined together placing wooden or iron fish plates on the opposite faces and securing these by passing bolt throught them.

SCARFED OR SPLICED JOINTS In this join, projection are made in the end of one piece and corresponding depressions are formed in the other pieces are then secured together by means of bolts, straps, fish plates and keys.

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TABLED JOINT These joints are formed when the member is subjected to both tension as well as compression. It is similar to splice joint but is formed by cutting special shape in both the piece and securing them with fish plate.

WIDENING JOINT These joints are called side joints or boarding joints and Used for extending the width of the planks or boards. The members are placed edge to edge. The flowing are the types: 1. Butt Joint : it is also known as square plain or ordinary joints 2. Rebated joint: It is formed by overlapping the cut portions.The joint remains dust proof after shrinkage of timber. 3. Rebated joint and filleted : It is formed by introducing wooden fillet in the rebated portions , having small depression. It is used for floors of factories etc. 4. Ploughed & tounged joint : It is formed by introducing wooden fillet in the grooves cut in the two pieces. 5. Tounged and grooved joint : It is formed by making fillet in one piece and groove in the other. 6. Rebated ,Tounged and grooved joint : It is formed by forming a rebate in addition to tounge and groove. Nail is placed in a such a way that it cannot be seen. 7. Splayed joint : It is formed by splaying the ends. The joint is used for only ordinary purpose.but superior to Butt joint. 8. Dowelled joint: It is formed by making groves in the center portion of end of each piece and inserting dowels of slate, gun-metal brass, bronze or copper. This is very strong joint. 9. Matched & beaded joints : it is formed by tounge and groove arrangement, & has special moulding on one side to give good appearance. 10. Matched & V-jointed joints : this is similar to beaded joint except that it is chamfered in V shape 11. Dove-Tailed Joint : It is formed by providing key of dovetail shape to fit in the corresponding grooves in the connecting members.

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BEARING JOINT It is provided when two members meet at right angle to give sufficient strength to function. 1. Halved Joint: These joints are formed by cutting through half the depth of each member meeting at right angle.so that top surface of both the member flush.

2. Notched Joint : It is formed by forming notch in 1 or both the members to be connected.

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3. Cogged Joint: This joint is formed by cutting small notch in the beam or timber member and providing notches on the lower member with a projection in the centre.The projection is known as cog. The upper portion, in which only small notch has been formed, retains its strength. 4. Housed Joint: It is formed by fitting the entire thickness of end of one member for a short distance into another piece. It is used in stairs in which the ends of risers & treads are housed in the strings. 5. Chased- Mortise Joint: This is used for jointing a subsidiary member to a primary member already fixed earlier. A chase or recess of wedge shape is formed in the main member while a tenon of corresponding shape is provided in the secondary member. 6. Dovetailed Joint : It is formed by cutting wedge-shape or flaring shaped pieces from each member and by hooking the projection of member into the other.This joint is used for curbs of skylights, and corners of boxes , cabinets , drawers. 7. Mortise – Tenon Joint : It is formed by cutting projection known as tounge or tenon, in one member which fits into slot, called mortise, cut into another. 8. Joggle Or Stump Joint : This is used for framing studs into the sill of a wooden partition wall.It is similar to mortise-tenon joint except that tenon is short in length and does not extend for full depth of mortised member.

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9. Bridle Joint : The joint is commonly used in wooden truss at the junction of struts and ties. It is formed by cutting a type of mortise in the end of one piece to fit in the bridle or projection left upon another piece. 10. Fox Tail Wedging Joint : the joint is formed by cutting a slightly dovetailed mortise to a lesser depth than the member. The tenon join is cut and two sockets are made in the tenon in which wedges are inserted. The entire assembly is then inserted into the mortise. 11. Tusk Tenon Joint : This joint is very strong and is commonly used in the timber floor construction.The joint is formed of tenon, tusk and horn.

FRAMING JOINTS Framing joint are used to construct the frames of doors, windows, ventilators etc. It is similar to Bearing joint except they are not supported to carry stress as compared to bearing joints.

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ANGLE OR CORNER JOINT Corner joint are used where 2 members are to be framed so as to form a corner or angular edge These joints are obtained by railing. Glue is used for making these joints And they are classified into : 1. Butt Joint : The members are connected just joining them edge to edge. 2. Grooved & Tounged joint : It is formed by fitting the projection of one member into the groove of the other. 3. Plain Mitred joint : it is formed by cutting the edge of both the members at angle. 4. Housed joint : in this an additional wooden member is inserted in the middle of the mitre joints 5. Mitred and feathered joint : it is formed by fitting on the member completely into the depression of the other. 6. Shouldered & Housed : in this only a part of member fits intothe corresponding depression of other. 7. Dove-Tailed housed Joint : This is a special type of housed joint in which one member is housed into the other by dovetail shaped projection and cut 8. Mitred and Rebated joint : it is formed by using a rebate in addition to a mitre. 9. Mitred Rebated & featured joint : the joint is formedby inserting a feater in the above joint. 10. Tounged, grooved & Mitred joint : This is formed by making tongue and groove in the lower edge of the mitre , to give improved appearance.

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OBLIQUE JOINT  Used where members to be joined meet at acute or obtuse angle. Ex. Timber trusses Briddle joint Mitred joint These are similar as previous condition except the angle Dove-Tailed joint Birds mouth joint : This joint is formed by cutting a angular notch in the main member, to which the other member is partly inserted and fitted. Oblique tenon joint : This is used for connecting a horizontal members both the membersbeing of bigger size. The tenon of inclined member is oblique, which fits into corresponding mortise hole of the horizontal members.

FASTENINGS [Type text]

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TOOLS USED IN CARPENTRY WORK

Marking Tools

Cutting Tools

Boring tools [Type text]

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Planing Tools

Hammers & Screw divers

Miscellaneous tools

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