Working With Timbers Flashcards
(59 cards)
Comb joints (finger joints)
This simple and effective joint is made from interlocking fingers which fit tightly together and are reinforced by glue. Accurate work can result in a very strong, aesthetically pleasing joint. Best creates using a router jig on natural or manufactured timbers or using a laser cutter on some materials.
Dovetail joint
Prized for their strength and aesthetics, dovetail joints are ideal for cabinets and drawer construction. Demonstrate a high level of skill but can be cut fairly easily with a router and a jig. Their strength relies on interlocking fingers and accurate marking and cutting. The dovetail shape means that these joints have superior directional strength.
Housing joints
A channel is cut through one piece of timber which houses a second perpendicular one. Used for shelves and dividers. It is fairly strong, when supported which glue but can be used without glue to separate sliding parts. Easy to make - only one piece of timber needs to be machined.
Half lap joint
Made by two overlapping materials glued together. Used in picture frames, doors and cabinet making. Quick and easy to make but not particularly strong. The shoulder helps resist diagonal distortion.
Dowel joint
Quick, simple, simple method to join a variety of materials. Holes are machined easily with a drill and jigs can be used to speed up the process further. Cost effective alternative to mortise and tenon joints. Joints can be reinforced with glue and help ensure that the pieces are in the correct orientation for flat pack furniture.
Mortise and tenon
Heavy duty joint used in load bearing timber frameworks. With high shear strength , it’s used in traditional building construction and frames for table and chairs. The tenon may be glued or pined in place. Wedges cab be used to secure it, adding an aesthetic feature. Joint has been developed to be made easily using CNC machines and is often used in flat pack furniture.
Screws
Most screws are made from mild steel and are plated in brass, zinc, chrome or another non-corrosive metal. Easy to install and can join dissimilar materials. Phillips and slot head screws are common head shapes. Self tapping screws dont always need a pre-drilled pilot hole and twin drive threads drive into timbre in half the time.
Pilot holes
Allow the core of the screw to pass into the material while the thread bites into the sides.
Clearance holes
Allow components to drop in and out without friction. Required when using nuts and bolts.
Coach bolts
Identified by a square section just under the head of the bolt. Materials must be prepared with a pre-drilled hole and the fixing is tightened with a spanner or socket set. The square section embeds into the wood and prevents the bolt from sprinting during assembly. Once installed, it’s impossible to remove from the head.
Knock down fittings
Offer strong but collapsible joints ideal for flat pack furniture. Glue free dowels are used to help locate parts and add stability.
Modesty blocks
Preformed blocks are hidden inside the product once installed. Used for carcass construction, to support edge to edge joints and in modular furniture. Easy to use but not very strong and the block affects the aesthetics and inside shape of the product.
CAM fittings
Require highly accurately pre-drilled holes to function properly. Jigs or CNC can be used to prepare parts for assembly but once cut, joints can be assembled easily with a screwdriver.
Barrel nut and bolt
Jigs can be used to ensure accurate positioning of the holes and the joint is easily tightened with and Allan key. The bolt tightens the barrel nut which is installed perpendicular to the bolt shaft. These fitting have excellent shear strength and clamping force ideal for load bearing furniture.
Laminating
Thin veneers or flexible plywood are glued together to make a permanent curved profile.
Lamination process
Moulds are covered in wax or parcel tape to prevent the laminate sticking the the mould. The mould must allow for the thickness of the laminate. Even coatings of glue give uniform strength to the laminate. Laminate is placed on a one part mould and encapsulated in a heavy duty polythene bag. A pump sucks the air from the sealed bag and the pressure forces the laminate into position.
Steam bending
A steam box heats and softens the wood fibres to make them pliable and easier to bend. Woods with a straight grain and open pore structure are ideal e.g oak, beech, ash. Steamed wood can be bent in all directions to form complex shapes. Used for small, lightweight projects as well as structural load-bearing forms.
Steam Box
Steam must be able to circulate around the workpiece and excess water and steam must be able to escape. Steamed wood must be moved quickly to a robust former to cool. Steamed wood must boxes take many forms but all are made of a vented container and a steamer of some kind.
Forming steamed timber
The dormer design depends on the shape required but the size and thickness of the timber used. Thicker material and more complex shapes require a more robust former. Thinner material formed into simple or shallow bends can be held with strings or straps.
Before you turn a square timber on a lathe
You need a rough stock prepared to make it easier to turn.
Turning timber
The prepared stock is secured in a wood lathe at both ends. Holding the workpiece at both ends give extra stability to long, think workpieces. Rotation speed should be reduced to cope with larger diameter pieces and increased for narrow lengths.
Faceplate on a wood lathe
The workpiece is screwed into the faceplate, then the faceplate is screwed into the lathe. This gives a very secure hold, especially for larger pieces. Alternatively, the faceplate is screwed into a wooden disk which is temporarily glued to the workpiece - a paper separator allows the workpiece to be removed easily.
Router bearing
Called a roller wheel runs along the workpiece to ensure that the bit does not go too far into the material.
