काष्ठकारी में, अधिक जटिल पुर्जे बनाने के लिये लकड़ी के कई टुकड़ों को जोड़ना पड़ता है। इनको ही 'संधि' कहते हैं। कुछ सन्धियों पर चिपकाने वाले पदार्थ, फास्नर (fasteners) आदि भी लगाने पड़ते हैं जबकि अन्य सन्धियों पर बिना इनके ही केवल लकड़ी ही सीधे लकड़ी जुड़ती है। संधियाँ विभिन्न प्रकार की होतीं हैं। इनके मुख्य गुण हैं- शक्ति, लचीलापन, देखने में संधि की सुन्दरता आदि। आवश्यकता के अनुसार उचित सन्धि का चयन किया जाता है।
The end of a piece of wood is butted against another piece of wood. This is the simplest and weakest joint. Of those, there is the a) T-butt, b) end-to-end butt, c) T-lap d) Miter butt and e) edge-to-edge butt.
Also known as open tenon, open mortise and tenon, or tongue and fork joints, this joint is where the through mortise is open on one side and forms a fork shape. The mate has a through tenon or necked joint. Bridle joints are commonly used to join rafter tops, also used in scarf joints and sometimes sill corner joints in timber framing.
The end of a piece of wood is butted against another piece of wood. This is reinforced with dowel pins. This joint is quick to make with production line machinery and so is a very common joint in factory-made furniture.
Also called a housing joint or trench joint, a slot is cut across the grain in one piece for another piece to set into; shelves on a bookshelf having slots cut into the sides of the shelf, for example.
A stub (the tenon) will fit tightly into a hole cut for it (the mortise). This is a hallmark of Mission Style furniture, and also the traditional method of jointing frame and panel members in doors, windows, and cabinets. This joint is a good strong joint to use.
Dowel: A small rod is used internal to a joint both to help align and to strengthen the joint. Traditional joints are used with natural timbers as they do not need any other materials other than the timber itself. for example: Butt joints. Dowel joints are also useful for pegging together weaker, cheaper composite materials such as laminate-faced chipboard, and where limited woodworking tools are available (since only simple drilled holes are needed to take the dowels).
संधियों की गुणवत्ता बढ़ाने के अपरम्परागत तरीके[संपादित करें]
Biscuit joints: A small 'biscuit' is used to help align an edge or butt joint when gluing.
Domino joiner: A trademarked tool similar to a biscuit joiner, where a piece larger than a biscuit has some of the advantages of dowels, and some of the advantages of biscuits.