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Practical Woodworking. S3 Exam Revision Topics N5. Wood Introduction. Woods can be classified into 3 main groups; Softwoods , Hardwoods & Manufactured Boards.
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Practical Woodworking S3 Exam Revision Topics N5
Wood Introduction Woods can be classified into 3 main groups; Softwoods, Hardwoods & Manufactured Boards. Softwoods: These come from coniferous trees (trees that have needle like leaves and last throughout the year) these grow quickly and can be replaced quickly after being cut down. Softwoods are relatively cheap to buy.
Wood Introduction Woods can be classified into 3 main groups; Softwoods, Hardwoods & Manufactured Boards. Hardwoods: These come from deciduous trees (trees that lose their leaves every winter). They grow slowly and sometimes have twisted trunks. They are often not replaced when cut down and take a long time to grow. Their wood is Expensive and used for high quality products.
Wood Introduction Woods can be classified into 3 main groups; Softwoods, Hardwoods & Manufactured Boards. Manufactured Boards: These are made from waste wood left over from machining or working. All excess such as thin sheets (plywood), small strips/blocks (blockboard), wood chips (chipboard) and saw dust (MDF) are used to make boards. Manufactured Boards are used to manufacture furniture due to the material being available in large sheets and because it does not warp.
Man-made Boards Plywood Blockboard MDF (Medium Density Fibreboard) Chipboard Hardboard
Timber Joints The majority of joints used in woodcraft have been designed specifically to attain the maximum possible strength in the model they are holding together. The type of joint selected will depend on what is being constructed i.e. what forces are going to be exerted upon the artefact. The selection is also dictated by the final appearance. i.e. in furniture manufacture it is normally important to hide the joint, as a piece of furniture which has a strong joint construction but if the joints are showing it will not be very pleasing to look at and ultimately potential customers would most likely avoid buying such furniture. Butt Joint Butt joints are the quickest and simplest to make but are not very strong. They generally need dovetail nailing to increase the overall strength of the joint.
Dowelled Joint These joints are both neat and strong. The holes must be lined up exactly but this can be done using a dowelling jig. The dowel will have a groove in the length so as to allow excess glue to escape. Through Housing These joints are simple to make and are suitable where the two parts being joined together are the same width. Stopped Housing These are harder to make, but are neater because the joint does not show on the front edge.
Haunched Mortise & Tenon Joint This joint is used where the rail of a table will join into the top leg of the table. This could be regarded as a hidden joint. Dovetail Joint This type of joint is very strong and can be only pulled apart in one direction. It is mainly used to construct drawers and boxes. Haunch
Through Mortise & Tenon Joint The mortise & tenon joint is the strongest tee joint and can be further strengthened by wedging or dowelling. Corner Rebate Joint The rebate joint is a very similar woodwork joint to the butt joint but the big difference between the two is that one of the ends of the timber has a groove cut out of it to create much better holding strength.
Mortise-Marking Out & Hand Cutting Mortise Gauge
Mortising Machine Setup Mortising Machine setup video. Click the image on the left to watch.
CORNER / REBATE / LAPPED JOINT The marking gauge is used to produce a line across the end of a piece of wood and down the sides a little. A try square is then used to extend the line across the side of the wood. The second saw cut is carried out with the wood held firmly in a vice. One of the saw cuts can be made using a tenon saw and a bench hook. Normally the wood is clamped down so that it is less likely to move during sawing.
FINGER OR COMB JOINT If the joint is cut accurately the ‘fingers should fit together without any gaps and the glue ensures that they are virtually indestructible. They are used for a wide range of products including jewellery boxes, cabinet construction, kitchen cupboards and many others. (Example below - a box containing an electronic game for a young child - notice the finger joints) This a good example of a ‘finger’ or ‘comb’ joint. It is ideal for box constructions and is suitable for use with natural woods such as pine and mahogany or even manmade boards such as plywood and MDF. The joint is strong especially when used with a good quality glue such as PVA (woodworkers adhesive) or cascamite.
Knock Down Fittings • Knock-down fittings are joints that can be put together easily. Normally people only need a screw driver, a drill, a mallet/hammer or other basic tools to put them together. They are temporary joints although many are used permanently to join together items such as cabinets and other pieces of furniture that are purchased in a flat pack. • Common Knock down fittings are: • Plastic or wooden corner blocks • Cam lock fittings • Scan fittings Wooden corner Block Plastic corner Block A piece of material such as pine can be drilled and screws can be passed through these holes. The corner block is pressed against the two pieces of material This gives a cheap and effective knock-down joint. The screws are normally countersunk into the knock-down fitting. Screws are used to fix the block into position. This type of joint is used to fit modern cabinets such as those found in a kitchen. It is a relatively strong joint and it has the advantage that it can be dismantled using a screwdriver.
Cam Lock Fittings The disk fits into a recess in the first side of the cabinet. It rotates by inserting a screwdriver into the slot in its side. The shaft is screwed into the second side of the cabinet. The collar of the shaft is passed through the hole in the second slot in the disk. When the disk rotates the shaft is locked in position. This keeps both sides of the cabinet locked together.
SCAN FITTINGS These are strong enough to be either permanent or temporary joints. The cylinder is inserted into the first side of a cabinet in a pre-drilled hole. The screw is then pushed through the hole in the second side until it meets the cylinder. It can then be tightened with a screw driver until both sides of the cabinet pull together.
Wood Screws Material Type: Ferrous metal- Carbon Steel, Stainless Steel. Non Ferrous- Copper, Brass, Bronze. Surface: Plain, Zinc Plated, Black Japanned etc. Recess: Slotted, Phillips, Pozi-drive, Torx. Head: Flat, Pan, Round, Raised, Hex, Bugle.
Wood Screws Screws are used to fit materials such as chipboard, MDF and natural woods together although there is a type of screw called a self-tapping screw that can be used for joining thin metal sheet. screws can be used to join materials together permanently although as they can be unscrewed with relative ease they are also good as a way of fixing materials temporarily. CHIPBOARD SCREWS: The thread on this type of screw extends all the way along the length. It is best used with chipboard RAISED HEAD SCREW: Used to fit door handle plates and decorative features that must look good. DOME HEAD SCREW: Can be used for fitting fixtures such as mirrors. The 'cap', which is the dome shape is usually chromed or made from brass and this can be a good feature. It also makes the head of the screw safe as the doom has no sharp edges to catch and cut hands/fingers. SELF-TAPPING SCREWS: these are normally used to cut a thread in metal. A hole is drilled in the metal, a fraction smaller than the width of the screw. The self-tapping screw is then turned into the hole cutting a thread. 1. Mark the position of the screw on the top of the wood.2. Drill a clearance hole through the top piece - the same diameter as the shank.3. countersink the hole if using a countersunk screw.4. Put the two pieces of material together and drill a smaller diameter hole in the second piece of material5. Place the screw in the top first hole and tighten carefully with a screwdriver. JOINING MATERIALS USING SCREWS
Machine Tools - Drills Cordless DrillThis does the same as the bench and pillar drill, but because it is not attached to anything it can drill holes in more awkward areas. This can also be used as an electric screwdriver if the drill bit is changed for a screw bit. Drill Bits
A Forstner bit is a cylindrical drill bit used to bore large diameter, flat bottomed holes into wood. It is particularly popular in furniture making and other large-scale woodworking projects in part because of its ability to drill deeply and precisely.
Hand Tools Marking Gauge Try Square Tenon Saw Mallet Cross Pein Hammer Saw Kerf Bevel-edged Chisel
Hand Tools - Cramps Sash Cramp G Cramp
Pillar drill The bench drill is a smaller version of the pillar drill. This type of machine drill is used for drilling light weight pieces of material.The example below shows the machine operator drilling a thin piece of perspex. The perspex is held safely in a hand vice which is held in the hand. NEVER hold work directly in the hand when drilling.The on and off buttons are found on the left hand side of the machine and the handle controlling the movement of the drill on the right.Most pillar drills will also have a foot switch for turning off the drill.
Machine Tools Cordless Drill Orbital Sander Belt Sanding Machine Mortising Machine Jig Saw
Woodwork Lathe Lathe Tools
Sustainability, Recycling and the Environment Forrest Stewardship Council
