This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
A chase mortise joint, or one formed by slipping the edge of a board, etc, into a dovetailed, rectangular, or other groove or chase, is so called. By cutting channels in the proper direction for the dowel holes, a new board may be slipped into place in a do welled floor without disturbing the existing dowels.
Slip Feather Joint occurs when equal-sized grooves are worked on the edges of two boards so that there may be closely fitted into and between them either a slip of fir cut more or less obliquely across the grain, or else a slip of wood harder than the boards, or even, as frequently happens, a strip or tongue of hoop iron. This cross tongue or slip of wood is, as well as the iron tongue, denominated a slip feather, which, however, when of wood is sometimes of dovetail section, and then it has to be inserted endwise. The slip feather in a keyed mitre joint loses this designation as soon as fixed.
This occurs in handrailing, as noticed under Handrail Joint.
Sprigged Joint is made in joiner's work when mouldings, instead of being stuck or struck in the solid on the edge of framing, etc, are merely worked on separate slips and planted on, or laid in, or bradded, or sprigged, to produce, if possible, an equal effect.
Spring Joint is one that is improperly loose, and often very objectionable in stairs and flooring, causing a springy step or board.
This is the same as a Butt Joint.
Square Edged Joint occurs in boarding when the butting edges are either merely sawn square or else shot true.
One that is continued for some distance in the same direction without a break. In flooring the straight joint floor obtains its name from the longitudinal joints having no breaks, owing to the boards being gauged to the same width.
This has been described under Chamfered Joint.
This may be made either to retain or not admit water. A slip feather between boards forms an excellent joint when the former is the object. The angle joint necessary in uniting the parts or sides of water trunks, cisterns, troughs, etc, may be either plane or similar to that known and described as cistern joint, but in any case it must be sufficiently close to be impervious. Cistern covers are sometimes protected at the joints by laying over them saddle-back fillets so throated as to form in conjunction with grooves in the boards water channels along each side of the joint. A junction, however, that is devised not to admit water is, perhaps, more correctly styled a weather or weather-tight joint.
This has been already defined in Section III. and elsewhere. Bain and wind are as far as possible kept out of the meeting stiles of casements, as explained under Hook Joint, and at the hanging stiles by opposite grooves in the stiles and rebates forming channels leading to another in the wood sill, from which holes convey the water off to the outside. Sometimes the stiles and rebates are tongued and grooved. It is a more difficult matter to prevent wet from entering between the bottom rails and sill when the casement opens inwards. The most usual device is some form of galvanised iron or metal water bar screwed to the oak sill with an overlapping throated weather board. The water bar may be hinged so as to fall flat when the casement is opened and return to its normal position when it is again closed. A small india-rubber tube fastened to the wood sill by means of a projecting edging or lap, and secured just under the bottom rail, has been substituted for a water bar, and sometimes the rails and pitch pine or oak sill are both rebated and grooved so as to interlock. A grooved channel should always run along the wood sill with communications bored through to the outside to conduct the water that beats into the room back again to its more appropriate quarters. Small fillets, called water fillets, are nailed over the joints of flaps, trap and other doors, etc, to keep out rain, and splash boards are placed for the same reason slantwise on the bottom rails of outer doors. In skylights in a sloping or lean-to roof the frame of the light is grooved to fit down upon a corresponding wood or metal tongue in the curb or lining, and the glass projects over the bottom rail without any horizontal bars. Under Sliding Joint will be found an allusion to a similar protective arrangement suitable, amongst other applications, to a slightly inclined running light of a raised skylight on a flat roof.