1. There are 2 classification of wood joints:
Year 9 RM Wood
There are 2 classification of wood joints:
Permanent joints:
Butt
This is the simplest form of joining timber and as the name suggests the lengths are simply butted together and glued. Commonly used in picture frames, skirting boards. Mitre Box Jig can aid cutting Mitre Joints.
Process
Ensure ends of both section are perfect 90° angles. Glue ends and clamp
Advantages:
Simple
Disadvantages:
Weak with only glue to support it
End grain will absorb a lot of the glue
Can require additional aids such as dowelling
Lap
As the name suggests the end of one length laps over the other.
Used in the manufacture of drawers, boxes and timber framed buildings. Lap joints can be "full" or "half".
Process
Mark out the lengths. Saw slightly deeper than required (to allow for sanding).
Glue and clamp joint
Advantages:
Simple
Stronger than a butt joint
More surface area to glue.
Disadvantages:
Relatively weak
Will require extra reinforcement
Housing
A housing joint is a groove cut to allow a length to slot into place.
Used in the production of shelving and cases.
Process
Mark out the housing ensuring it fits the thickness of the 2nd length. Saw and chisel out the housing. Glue 2nd length into housing.
Advantages:
Relatively strong
Simple construction
Disadvantages:
Not as aesthetically pleasing as other joints.
Dovetail
The dovetail joint is one of the most popular joints because it is attractive and has good tensile strength (difficult to pull apart). A series of pins and cuts are cut into the end of the lengths, these triangular shapes then lock together.
Process
Mark out the tail board. Using a dovetail saw, cut the tails, and finish with a fret saw, then finish off with a chisel. Use the tails to mark out the pins, using the tails as a guide. Using the same process as cutting the tails to cut the pins. Attach, glue and sand or plane to finish.
Advantages:
Very strong
Aesthetically pleasing
Needs no extra support
Disadvantages:
Complex to construct but a jig can be used
A comb joint has both lengths of timber evenly spaced - a rectangular cut that allow the lengths to lock together. A comb joint is also called a finger joint or box joint and is used in furniture manufacture and floor boards.
Process
With care, plan out the size of the combs and mark out the end of one length. Using a tenon saw cut the marked length and chisel to the line. Use the cut length to mark the end of the second length. Cut the second length, Lock together and glue
Comb/
Finger
Advantages:
strong joint,
A jig can be used for faster comb cutting
Plenty of gluing surfaces
Disadvantages:
Can look busy
Time consuming to cut

2. Mortise and Tenon Temporary joints: Finishes
A strong joint., used in frame joints for chairs and table legs. Its name comes after to tools that are used to make them- tenon saw, mortise chisel. The mortise and tenon joint functions by inserting one end of a piece of wood into a hole in another piece of wood.
Process
In commercial production, the mortise is milled out so the tenon is machined with a rounded edge. The smaller end of the wood is the "tenon," and the wood with the hole in it is referred to as the "mortise." Glue is used to secure the pieces together and variations on the joint also use pins and wedges to lock the joint in place.
Mortise and Tenon
Advantages:
Strong joint
Long lasting
Decorative
Resist forces well
Disadvantages:
Time consuming
Require skill- difficult to make
Special tools needed
Temporary joints:
There are many different types of temporary joints:
Nails
There are many different type of nails, but used on their own they can make a joint very weak.
Nails are used for:
Holding wood together, whilst glue dries
Fixing the backs of cupboards
General DIY work
Dowel
Easy to produce and popular in commercial production as it relies on aligned holes and pegs (dowels). Are widely used when produced are produced for home assembly
Screws
Often also combined with glue. Lots of different types available but massive increase in cross head screws as they are easier to drive in. e. Can be very strong when used across the grain
It can prevent wood from rotting away by protecting it.
Finishes
Polish
This is applied to wood to protect it from moisture, insect attack, enhances the colour of the grain and makes it easier to clean the surface
Varnishes & Lacquers
These are available in oil, water and solvent based
Wax
The wax fills the porous surface of the timber and layers are built up on the surface to protect the finished product
Oil
Some timbers such as teak are naturally oily. Applying oil helps improve the appearance of the grain. It also protects it for out door use. Vegetable oil can be used on timber that will come into contact with food.
Painting
These are available in oil, water and solvent based, help to enhance the visual appearance of the finished product.