Copyright © 2015 Timber Framers Guild TFG Glossary of Terms 2015 KEY TO CROSS-REFERENCE TERMS See also See a related, similar thing Cf. Compare a related, dissimilar thing Also Another name for the same thing (q.v.) Which see ABUTMENT. In joinery, the end of one timber touch- BASKET HITCH. Open sling configuration for lifting ing another. See also BUTT JOINT. timber. Cf. CHOKER HITCH. ADZE. Handled edge tool (various patterns) with its BAY. Crosswise volume (perpendicular to roof ridge) in a edge at a right angle to the handle, used to shape or dress building, bounded by two bents or crossframes. Cf. AISLE. timbers. BEAM. Any substantial horizontal framing member. AISLE. Lengthwise volume (parallel to the roof ridge) in BEARING. Area of contact in a joint through which a building divided into several such spaces, usually three. load is transferred. Cf. BAY. BED TIMBER. Short, stout timber used to distribute ANCHOR BEAM. In a Dutch barn, the major tie beam concentrated loads at bridge piers and abutments. joined to H-bent posts, generally by outside-wedged BEETLE. Large wooden mallet typically weighing 15 to through tenons. 30 lbs. Also COMMANDER, PERSUADER. ANGLE TIE. Horizontal corner brace at plate level, often BENDING. Deviation from straight resulting from the combined with a dragon beam (q.v.) under hip roofs. application of force. In a bent member, the concave sur- ANISOTROPIC. Material whose structural properties face is compressed, the convex surface is tensioned and the are not identical in every direction. neutral axis is unaffected. ARCH BRACE 1. Curved brace. 2. Brace rising from BENT. 1. Assemblage of timbers perpendicular to the bridge abutment to support lower chord of truss. ridge, usually the crossframe of a building, sometimes ARRIS. Line along which two adjacent surfaces meet. In including rafters, assembled on the ground and then some square rule (q.v.) carpentry, the reference line formed reared up into position. 2. One of the supporting frames by the meeting of two datum (reference) planes. of a railroad trestle. ASHLAR PIECE. Short vertical strut near the foot of a BEST EDGE. On a timber to be laid out, the secondary rafter, joining it to a sole piece at the top of a masonry reference surface adjacent to the best face. wall. BEST FACE. On a timber to be laid out, the primary ref- ASSEMBLY MARKS. See CARPENTERS’ MARKS. erence surface, which will typically receive flooring or wall AUGER. Handled edge tool for boring holes in wood. and roof sheathing. Not an appearance term. AXIAL LOAD. Force applied along member’s neutral BEVEL. Any nonorthogonal angle taken through the axis. breadth or depth of the material; the tool to measure or lay BACKING. Top surface of a hip or valley rafter, beveled out such angles. to follow the slopes of adjacent roof surfaces. The hip BINDING JOIST. Floor timber, often lying perpendi- backing is thus convex, the valley backing concave. cular to the ridge, connecting posts and carrying common BAREFACED DOVETAIL. Dovetail (q.v.) flared only joists; joist resting on the wall plates and carrying other on one edge, suitable for mortising as well as housing. See joists. Cf. BRIDGING JOIST. also HALF-DOVETAIL. BIRDSMOUTH. 90-degree notch cut into the lower BAREFACED TENON. Tenon flanked by only one end of a rafter to fit the upper inside corner of the plate. shoulder. Cf. CROWSFOOT. BARGE BOARD. The board covering the ends of BISAIGUË. Forged, double-ended cutting tool about purlins at the gable end of a roof. Also RAKE. the height of a worker, a mortise chisel at one end and a BASE CRUCK. Cruck with blades starting as posts and slick at the other and with provision for a wooden han- curving upward to end at the collar beam. See CRUCK dle near the middle, for chopping and trimming mortis- FRAME. es and smoothing work. Called a twybill in England. TFG Glossary 1 BLADE. 1. In a scarf joint, the termination of one half of BUCKLING. Irreversible bending of a timber as a result the joint so as to lap under the beginning of the other half. of a compressive force along its axis. 2. In a cruck frame, one of the paired rafters. BUILDER’S LEVEL. Rotating telescope set on a tripod BOLSTER. 1. Horizontal cap laid on the top of a post to and used for leveling a foundation or sill timbers. shorten the span of the beam supported by it. 2. The part BUTT 1. The end of a log that in the living tree stood at of the pier or abutment on which a bridge-truss rests. 3. In the ground; generally, the larger end. 2. End of a timber centering an arch, a crosspiece that connects the ribs and cut at right angles to its length. supports the voussoirs. BUTT COGS. Housed joints for full section of joist ends, BOLT-O’-LIGHTNING. Scarf form with many abut- usually closely spaced. Resulting narrow spaces between ments, whose jagged interface line resembles its eponym; housings in carrying timber resemble teeth in a gear rack. used in heavy work. Also Trait de jupiter. BUTT JOINT. Abutment (q.v.) of two timbers without BORING MACHINE. Hand-cranked device with gears penetration. to drive a removable auger bit, used to bore large or deep BUTTRESS. Reinforcing mass, typically masonry, built holes, as in roughing out a mortise or drilling pegholes. against a wall to counteract the thrust of an arch. BOW. Vertical deviation from straight in the length of a CAMBER. Hewn, sawn, natural or deliberately bent timber. Also CROWN. See also CROOK and . upward sweep in a beam or in its top surface, often incor- BOX. See HOUSING. porated into the lower chords of timber trusses, to resist BOXED HEART TIMBER. Timber whose section deflection (especially in bridges) or to obtain aesthetic includes the heart of the tree. Since checks generally do effects in the space below. Historic texts suggest adding not cross the heart, such a timber rarely splits completely. 1 in. of camber in 20 ft., in anticipation of sag (q.v.). See Cf. FOHC. also CRANK. BOX FRAME. Construction in which roof trusses are CANTILEVER BEAM. Projecting timber unsupported carried by a self-supporting structure of posts, tie beams at one end. and wall plates. Cf. CRUCK FRAME. CARPENTER’S MARKS. Incised matching marks at BRACE. Any oblique timber (permanent or temporary) joints to identify uniquely matching parts in a frame, that resists distortion of a frame. See also KNEE BRACE. made during test assembly; indispensable to scribe rule BRACED FRAME. Simplified timber frame with heavy (q.v.) method of layout. Other carpenter’s marks may posts and sills and light-framed floors and walls. Cf. FULL identify all members of one crossframe or wall assembly. FRAME. CARRYING STICKS. Sticks placed under a timber to BRACKET. Block tenoned or pegged to one timber to provide easy handholds for carrying it by more than one support another. Also cleat. person. BREADTH. See WIDTH. CASEHARDENING. Final stage of rapid seasoning or BREASTSUMMER (spelling variants). 1. Beam span- drying in which the surface of timber is in a state of com- ning a wide opening in an external wall, such as over a pression and the core is in tension, making the wood shop front, and supporting a framed wall above. 2. Timber prone to deformation when worked (J. Garvin 2003). forming the sill of a jettied (q.v.) story (Hewett 1985). CHAIN MORTISER. Jigged power tool with chain- BRIDGING JOIST. 1. Intermediate floor beam, often mounted cutters that plunge into the face of a timber to parallel to the ridge, connecting one beam to another and cut a mortise, fitted with a depth stop and other controls. carrying the ends of common joists. 2. A small beam or CHAMFER. Bevel cut at the long arris of a timber, run joist resting upon binding joists below and supporting right through or decoratively stopped before the ends. A boarding above. See also SUMMER BEAM. Cf. BIND- bevel at the leading arrises of a tenon, to ease assembly. ING JOIST. CHASE MORTISE. 1. Lengthened mortise for swing- BRIDLE. 1. Open mortise-and-tenon end joint, such as insertion of a tenoned member otherwise impossible to at a rafter peak or sill corner, with one end of the mortise insert in an existing assembly, such as a brace or a joist open (see TONGUE AND FORK). 2. An open mortise - added after assembly of main members. See also PULLEY and-tenon joint between the top of a post (the bridle) and MORTISE. 2. Mortise with one end angled to follow the a passing beam reduced in section to form the tenon. slope of a member such as a brace. BROADAXE. Wide-bladed axe with its edge usually CHECK. Separation of wood fibers along the rays, caused beveled only on one side, and fitted with an offset han for by the tension of differential radial and tangential shrink- knuckle clearance. Used to hew timbers from logs or for age or by surface fibers of a timber drying first and attempt- similar shaping work. ing to shrink around an incompressible, still-wet center. 2 TFG Glossary CHECK BRACE. Short, low-angle brace fitted behind a COMPRESSION. The state of stress in which particles principal post in a bridge truss as reinforcement. It trans- of material tend to be pushed together. fers back to a housing in the chord the horizontal compo- CONVERSION. Sawing, hewing or riving square tim- nent of the main brace load arriving on the front of the ber from the log. post. Also kicker (M.