01-03-2013, 10:12 AM
CARPENTARY WOOD JOINTS
CARPENTARY WOOD.ppt (Size: 3.44 MB / Downloads: 122)
INTRODUCTION – carpentry
Carpentry includes those forms of construction in wood which are subjected to stresses on account of the loads which they support or the pressures which they resist.
Permanent constructions as partitions, lintels, floors and roofs.
Temporary construction as scaffolding, shoring, timbering for trenches, centering for arches and form work to support reinforced concrete work during construction.
carpentry is regarded as constructional art of timber which is mostly done on the building site.
Joinery is used to indicate the art of preparing and then framing places of timber to form the internal fittings and finishing of houses.
joinery is used for delicate construction and for enhancing the architectural beauty of timber.
It includes the construction and fixing of timber works, such as doors, windows, stairs, floor boards, linings, cupboards, furniture etc.
In India, the work carpentry is only used to indicate both kinds of work namely, carpentry and joinery.
TYPES OF JOINTS
The following types of joints are used in timber construction to suit the different purposes—
Lengthening Joints
Widening or Side Joints
Bearing Joints
Framing Joints
Angle or Corner Joints
Oblique Shouldered Joints
lengthening joint- LAP JOINT
A lap joint is made by overlapping two boards.
Lap joints can be made to join boards at a 90 degree angle (as shown), no angle at all (that is, splice two boards into a longer one), or the two boards can form a cross.
This joint is ideal when you need to bring two boards together but keep them in the same plane.
It is very strong even without mechanical fasteners as there is a lot of gluable surface area in the joint.
The laps can be cut with either a saw, or a with a saw and a chisel.
Large lap joints should be cut with only a saw, but they can be trimmed with a chisel.
Widening joint – tongue & groove joint
Tongued and grooved joint - This joint is formed by fitting one member, having tongue on one side into the other member with a corresponding groove on the side.
A strong joint which requires glue, the tongue and groove joint is widely used for re-entrant angles.
The effect of wood shrinkage is concealed when the joint is beaded or otherwise moulded.
In expensive cabinet work, glued dovetail and multiple tongue and groove are used.
Framing Joints
These joints are almost similar to the bearing joints described above as regards the types and construction.
But these are slightly modified to meet special requirements because the primary consideration in their design is not strength, as in bearing joints, but endurance or durability.
These joints are used to construct the frames of doors, windows, ventilators and partitions, and hence known as training joints.