• Acclimation:

    Components kept together for a day or more prior to lay-up, so that their moisture contents have a chance to equalize. Top >>
  • Active Door or Leaf:

    The first operating door of a pair of doors. Top >>
  • Air Drying:

    Lumber is stacked with cross sticks to allow free air circulation all around and to allow the sap to harden naturally. Usually would still require kiln drying to finish. Top >>
  • Anchor Hinge:

    A heavy duty hinge which mounts on the top corner of the door, L-shaped, routed into the stile and the top rail of the door. Top >>
  • Annual Growth Ring:

    The ring seen on a cross section of a log or piece of wood caused by contrasting springwood and summerwood and denoting one year's growth of the tree. Top >>
  • Applied Molding:

    Applied to the surface of a door with either nails or glue or both to form decorative patterns. Lynden Door usually uses Z-bead, a distinctive molding for this purpose and stocks this bead in Red Oak. Top >>
  • Architectural Grade:

    The highest grade of door made, bonded & sanded when particle board, stave wood or strand lumber cores are used. Comes with a lifetime warranty complete with re-hanging and re-finishing provisions. Lynden Door, Inc. designates these doors as LD series. Top >>
  • Architrave:

    The group of moldings above and on both sides of a door or other opening. Top >>
  • Astragal:

    A small molding, plain or ornamented and usually flat or T-shaped, attached to the meeting edge of one leaf to bridge the gap between, hiding the meeting joint of a pair of doors. The edge without the astragal must be closed first to allow proper closure. They also can provide a weather seal, minimizing the passage of light or sound between doors or retarding the passage of smoke or flame during a fire. Top >>
  • Back-cut Veneer:

    A thin layer of wood cut as in half round-cutting except that the bark side faces in toward the lathe center. These veneers are characterized by an enhanced striped figure and the inclusion of sapwood along the edges. Top >>
  • Balance Match:

    Each piece of veneer in a face is of uniform width before trimming. This gives a symmetrical appearance but reduces veneer yield. Top >>
  • Ball Bearing Hinge:

    A heavy duty hinge which contains ball bearings for easy swing of the door. Top >>
  • Banana:

    Occasionally, while being trimmed, a door moves in the sizer. If it moves from one side to another and back it will take a "Banana" shape. This is easiest to see by putting two doors together and checking to see if they meet all along the edge, then flip one door over and check again. If they are banana'ed they will appear tight one way and will have a convex gap between them the other way. Measured corner to corner these doors appear to be square. Top >>
  • Barber Pole:

    An effect in the book matching of veneers resulting from tight and loose sides of veneers having different light reflections when finished. This is due to the different finish absorption rates on the differing sides. Top >>
  • Bark Pocket:

    A small area of bark around which normal wood has grown. Bark pockets appear as dark streaks on radial surfaces and as rounded areas on tangential surfaces. Top >>
  • Beading:

    A special molding for holding glass in a door lite. Also called Stop. Top >>
  • Bevel:

    The edge of the door is trimmed at an angle other than 90°. The 3° bevel is the most common. This reduces the chance of the door rubbing against the jamb since the width across the face of the wide side of the door is the same measurement as the diagonal from the edge of the wide side to the opposite edge of the narrow side of the door. Most doors now have bevels on both edges of the door creating a wide & narrow side, not a parallelogram. This moves the pivot point away from the jambs face. Top >>
  • Bifold Door:

    Usually used for a closet closure, this is actually two halves of a door which has been split lengthwise and then hinged and hung from a track with appropriate hardware to allow it to fold together when open and fold flat to close the opening. Top >>
  • Bird's Eye:

    A decorative feature, primarily in maple. This distortion of the fiber alignment appears as a series of small concentric circles like a bird's eye. The more of these circles the "heavier" the bird's eye is said to be. Top >>
  • Block Sanding:

    Sanding of doors using sandpaper wrapped over large flat wooden blocks to remove rub marks and small scratches to give an even face prior to finishing. Top >>
  • Blocking:

    Special pieces of material added into the core of a door for specific functions. Examples are mineral blocking for hardware in fire doors & robe hook blocks in hollow core residential doors. Top >>
  • Blue Stain:

    Stain or discoloration produced by the chemical action caused by the iron in the cutting knife coming into contact with the tannic acid in the wood. This is most noticeable in oak plywood. Top >>
  • Bonded & Sanded:

    The stiles and rails are bonded to the core, prior to the whole assembly being sanded to uniform thickness, before the application of the faces. Top >>
  • Book Match:

    The most common veneer match. Every second piece of veneer is turned over so adjacent pieces are opened like the pages of a book. The grains match and create a mirrored image at the joint line. Used in Rotary, Plain Sliced, Quarter Sliced and Rift Cut veneers. Top >>
  • Book Size:

    The full height and width of a door prior to pre-fitting. Top >>
  • Bottom Seal:

    A material or device which provides a weather tight seal between the bottom of the door leaf(s) and the threshold. Top >>
  • Brick Mould:

    The outside casing of a door frame, originally intended for installations in brick or masonry walls. Top >>
  • Brown Stain:

    A dark, often chocolate brown, discoloration found in the sapwood of some softwoods stored under unfavorable seasoning conditions. It is caused by a fungus. Top >>
  • Bull Nose:

    A rounded corner or edge used in positions where sharp arises might be damaged. Most stops on door frames are bull nosed. Top >>
  • Bullet Resistant:

    Doors which resist penetration by bullets. Door cores contain some material (i.e. Fiberglass) which is of varying thickness to obtain ratings for resistance to bullets fired from small arms up to high power rifles. Top >>
  • Burl:

    A swirl, twist or distortion in the grain of the wood which normally occurs near a knot or crotch. A burl can often be associated with abrupt color variation and/or a cluster of buds. Burls range in size from very small to a couple of feet across. Top >>
  • Butt Joint:

    A joint formed by square edge surfaces (ends, edges, faces) coming together; end butt joint, edge butt joint. Top >>
  • Butterfly Hinge:

    A special hinge which has one side fit inside another so its thickness is reduced. This hinge is used by Lynden Door to assemble bifolds. It reduces gap between the panels without requiring mortising. Except for the hinge knuckles, the hinge does not show from either side when the bifold is closed, making it ideal for room dividers. Top >>
  • By-pass Door:

    Usually used for a closet closure, this is actually two doors which are hung from a track so that each slides back and forth, one in front of the other so you can access either side of the closet by sliding the door in front of that side to the other side. Top >>
  • Casing:

    The molding around a door jamb/frame which hides the joint between the frame and the wall. Top >>
  • Caulking:

    Filler used in sealing openings, which is used to hold glass tight inside the beading in a door lite. Top >>
  • Center Match:

    Each face has an even number of pieces of veneer of uniform width to give a symmetrical appearance with a joint in the center of the panel. This match reduces veneer yield. Top >>
  • Ceramic Glass:

    Special glass which is more resistant to breaking than standard glass under high heat conditions. It can be used for larger openings than standard wire glass in fire doors. It is available in various thicknesses and types for different size and rating requirements. It is usually specified by brand name such as FireLite, Pyrostop or SuperLite. Top >>
  • Chalk:

    Veneer mills use chalk of various colors to highlight defects for repair or to give identification. Chalk is used because it is not absorbed into the wood and can therefore be sanded off completely. Top >>
  • Chamfer:

    A beveled corner. Top >>
  • Chatter:

    Lines appearing across the face at right angles to the grain giving the appearance of corrugations resulting from bad setting of sanding heads. This is easily seen in materials which have been planed but not sanded. Top >>
  • Checks:

    Small slits running parallel to the grain of the wood, caused by stresses in the drying of the wood. The wood dries too quickly, causing moisture to be trapped inside while the outside dries. As the outside shrinks, it cracks due to the inside still being swollen with moisture. Top >>
  • Clear Finish:

    A transparent applied finish. Top >>
  • Clear Lumber:

    Wood which is free of blemishes or defects. Top >>
  • Closer:

    A device designed to automatically close the door after it has been opened. It is required for all fire doors and is either surface applied or concealed. Top >>
  • Clustered:

    When a defect described in the grading rules is sufficient in number and close enough together to be concentrated in one area it is "clustered". Top >>
  • Comb Grain:

    The grain in quarter sawn lumber Top >>
  • Compatible Edge:

    When relating door stiles to face appearance the edge may not be the same species as the face, but it will be similar in overall color, grain, character, and contrast as the face. Abbreviated as CVE (compatible vertical edge) or CES (compatible edge stile). Top >>
  • Composite Blocking:

    Special fire retardant material used for core reinforcement in mineral core doors for the installation or application of special hardware. Includes lock or flush-bolt blocks, wide stiles or additional rails. Top >>
  • Continuous Hinge:

    A hinge which runs the full length of the door. Also called a piano hinge, these are typically surface mounted to the door and frame. Top >>
  • Continuous Match:

    Each piece of veneer runs from the top of a transom through to the bottom of a door giving a match at the joint. Provides an optimum utilization of veneer but is limited to the available veneer length. Top >>
  • Cross-banding:

    The center ply in a three ply plywood face or the core between the core and the face in a 5 ply construction door. Top >>
  • Cross Bar:

    An irregularity of grain resembling a dip in the grain running at right angles, or nearly so, to the length of the veneer. Top >>
  • Cross Break:

    A separation or break in the wood cells across the grain. Such breaks may be due to internal strains resulting from unequal longitudinal shrinkage, or to external forces. Top >>
  • Cross Grained Wood:

    Wood in which the fibers deviate from a line parallel to the sides of the piece. Cross grain may be either diagonal or spiral grain, or a combination of the two. Top >>
  • Curly-grained Wood:

    Wood in which the fibres are distorted so that they have a curled appearance as in “bird’s eye” wood. The areas showing curly grain may vary up to several inches in diameter. Top >>
  • Cylinder Lockset:

    The standard lockset in a door. Also called a 161 prep. This may or may not have a keylock on one side, depending on the use. Top >>
  • Dado:

    A rectangular groove which is cut with either a special saw blade or a router. Top >>
  • Deadbolt:

    A second lock separate from the door knob, usually positioned 6" - 12" above the cylinder lock. Usually consists of a key lock on the outside and a turn on the inside. This is usually used in exterior applications. Top >>
  • Decay:

    The decomposition of wood substance by fungi. Top >>
  • Delamination:

    Separation of plies or layers of wood or other materials due to failure of the adhesive joint. Top >>
  • Discolorations:

    Stains in wood substances. Some common veneer stains are sap stains, blue stains and those resulting from the chemical action of the glue on the wood. Top >>
  • Door System:

    An assembly including the frame, door leaf(s), sidelite(s), weatherstrip, threshold, and hinges, locks and other hardware, which, when installed, forms a barrier to the elements and to passage in and out of a building. Top >>
  • Double Acting:

    A door which is installed with special hinges so that it can swing both ways. These are sometimes small and called café doors. Full size doors often have the outer edge radiused so it does not rub in the jamb when swinging. These doors are often used in restaurants between the kitchen and the dining areas, allowing the staff to push through the doors from either side. Top >>
  • Double Egress:

    This is a type of a door pair where both doors have the same swing. The normal hanging method enables a person walking on the right side of the hallway to push the door open, regardless of which direction they are going. Top >>
  • Doze:

    A form of decay characterized by a dull lifeless appearance of the wood, accompanied by a lack of strength and softening of the wood substance. Top >>
  • Dry Rot:

    Decay caused by certain fungi which are peculiarly adapted to supply their own moisture requirements. The fungi always commence growth in moist wood, but later spread to dry wood due to the development of special water conducting organs. Top >>
  • Dunnage:

    Material, such as 2" x 4" ‘s or 1" x 6" ‘s, used in the packaging of doors to prevent direct contact with other surfaces which could mar or damage the door. Top >>
  • Dutch Door:

    A door which is divided horizontally into two leaves. The top leaf may open independently of the bottom, but opening the bottom usually opens the top as well. The bottom leaf is often equipped with a shelf, either single or double sided. Top >>
  • Ease:

    Slightly shaving or rounding the longitudinal and horizontal edges of the door skins on a door to remove the sharp corner and prevent the face being chipped due to something being rubbed against the door edge. Top >>
  • Edge Band:

    A veneer or laminate strip along the outside edges of the two stiles and/or the top and bottom rails, usually to match the face of the door. Top >>
  • Edge Grain:

    Wood that has been cut so that the wide surfaces are approximately at right angles to the annual growth rings. Lumber is considered edge grain when the rings form an angle of 45o to 90o with the wide surface of the piece. Top >>
  • Edge Joint:

    A joint between two pieces of wood glued edge to edge in the direction of the grain. Most hardwood doorskin veneers are now made this way. Top >>
  • Electric Strike:

    A special strike in a jamb where part of the strike mechanism, on receiving an electric signal, opens to allow the door to open, even though the lock is still closed. Top >>
  • End Match:

    Paired pieces of veneer or door faces are placed end to end to give a mirror image, thus giving the impression of a continuous match joint. Top >>
  • Equilibrium Moisture Content:

    At this moisture content, material neither gains nor loses moisture when it is surrounded by air at a given relative humidity and temperature. Top >>
  • Exit Device:

    A door locking or latching mechanism which is designed to be operable in the direction of egress travel in an emergency. The locking or latching mechanism releases through pressure on a touch/push “panic” bar. If tested and approved, exit hardware can bear a fire rating label certifying its suitability for use on fire-rated emergency doors. Such hardware may be one of the following:

    Mortise Type: having the lock mechanism mortised into the edge of the door or concealed within the door.

    Rim Type: having the lock mechanism mounted on the interior face of the door.

    Vertical Rod Type: surface or concealed, having the latches in or on the top and/or bottom of the door and activated by the cross bar through a rod linkage extending vertically on or in the lock stile of the door.

    Top >>
  • Feather Grain:

    A slight separation of spring wood and summer wood fibres on veneer surfaces. Top >>
  • Feet:

    The term used to describe small blocks of wood or metal "buttons" placed on the bottom corner of each door, to allow the door to be stood upright without having the finished edges of the door contacting the floor Top >>
  • Fiddleback:

    A type of figure with a ripple look. It is an undulating appearance of a smooth surface veneer. It has a fine wavy grain common in sycamore and maple. It is often used for the backs of violins. Top >>
  • Figure:

    The pattern produced in a wood surface by annual growth rings, rays, knots, deviations from natural grain, such as interlocked and wavy grain, and irregular coloration. Top >>
  • Finger Joint:

    A series of interlocking fingers precision cut on the ends of two pieces of wood which mesh together and are held rigidly in place with adhesive. Top >>
  • Fire Rating:

    Doors which have been specially manufactured in such a manner that when installed in an assembly and tested, will pass ASTM E-152 "Fire Test of Door Assemblies" and can be rated as resisting fire for 20, 45, 60 or 90 min. Top >>
  • Flake:

    Portion of a ray as it appears on the quartered surface. Flake can be a dominant feature in oak. Also called Fleck. Top >>
  • Flecks:

    Spots or marks caused by irregularities in the grain. Top >>
  • Flush Bolt:

    A piece of hardware routed into the edge of one leaf of a door pair which, when activated, locks the door into the jamb header or into the floor, thus making the door "inactive". Flush bolts are often used in upper and lower pairs, giving "two point latching". The active door then usually locks into the inactive door. The pair has "three point latching." Top >>
  • Flush Cut:

    Straight cut, not rabbeted, having a surface level with an adjacent surface. Top >>
  • Flush Pull:

    A handle or grip designed for flush attachment to a door to facilitate opening and closing. Top >>
  • Flutes:

    Hollows or grooves cut longitudinally into a door for decorative purpose. Top >>
  • French Door:

    A door with the majority of its center cut away and replaced with glass. In a stile and rail door it is normally composed of several small lites. In a flush door it usually has a single, almost full door size piece of glass. Top >>
  • Function Hole:

    The main holes cut or drilled through the faces of the door for the mechanisms of a lock to fit into. Complexity of function holes vary widely, with the simplest being a single hole for a cylindrical lock to detailed, multiple holes for electronic locks. Top >>
  • Georgian Polished Wire Glass:

    Glass which has a ½" wire mesh inside it for additional strength. This glass is the minimum required for fire door applications. Top >>
  • Glazing:

    Process of installing glass into a door, transom or sidelight. Top >>
  • GP Firestop:

    A special fire door material with superior fire resistance, high screw holding strength, split resistance and inherent cooling properties which make it ideal for both fire door edges and interior blocking. It is basically comprised of recycled fibers and gypsum. Used properly, it can replace metal edges and astragals required for pairs of fire doors. Top >>
  • GP Meeting Edge:

    Georgia Pacific builds our mineral core fire cores and components. On Neutral Stiles Pressure pairs, if a metal edge is not being used where the doors meet, special construction stiles are required. Top >>
  • Grade:

    The quality or classifications of lumber and/or plywood in relation to its adaptability for different uses. Top >>
  • Grading:

    Describing the act of sorting wood materials into different categories for different uses. Lynden Door re-grades every doorskin which enters our plant to make sure they are all up to our standards. Most door plants do not do this additional grading. Top >>
  • Grain:

    The direction, size, color and texture of the fibers in wood or veneer. Top >>
  • Grain Slope:

    Describes the angle of the grain to the edge of the veneer or door. Top >>
  • Grain Sweep:

    Describes the angle of the grain to the edge of the veneer or door over an area extending 1/8 of the length of the piece, a curved section. Top >>
  • Green:

    The term used to describe lumber which has just been cut or wood which has not yet been dried. Top >>
  • Hairline:

    Thin, barely perceptible line showing at the joint of two pieces of wood. Top >>
  • Half Round Slicing:

    A variation of the rotary veneer cut in which segments of the log are mounted off center in the lathe. The resulting cut travels slightly across the annual growth rings and shows modified characteristics between rotary and plain sliced. Top >>
  • Handing:

    The manner in which a door swings. It is best shown in a diagram and has four terms: right hand, left hand, right hand reverse and left hand reverse. Right hand and left hand reverse are the same until the hardware is applied, as are left hand and right hand reverse. The hardware makes the difference. Top >>
  • Hardboard:

    A composite doorskin made up of layers of fiber pressed into a hard skin. Sometimes this fiber is pressed into a mold and results in molded panel doorskins. Top >>
  • Hardwood:

    A description applied to woods from deciduous (annual leaf dropping) and evergreen broad-leaved trees (dicotyledons). This term does not infer hardness in its usual sense, but is a classification only. Generally, the wood from broad-leaved trees is harder and heavier than that from needle-leaved trees, but there are numerous exceptions, (i.e. Balsa is one of the lightest and softest woods, but is a hardwood.) Examples are Birch, Oak, Maple, Cherry, Teak, Walnut and Mahogany. Top >>
  • Hardwood Edge:

    The edge of the door is made from hardwood. This may be either an edge band or a full stile. Written as hardwood vertical edge (HVE) or hardwood edge stile (HES). Top >>
  • Header:

    Also called Head Jamb. The piece of the door frame across the top of the door. Top >>
  • Heartwood:

    The non-active center of a tree generally distinguishable from the outer portion (sapwood) by its darker color. Top >>
  • Hinge:

    The hardware on which a door swings. Top >>
  • Hollow Core:

    A slight misnomer - it describes a light weight door where large sections of the core are hollow. Most flush doors have a paper (kraft) core made up of corrugated paper (cardboard) which opens up into a honeycomb of cells to give the door skins support and to add to the doors structural stability. Top >>
  • Hose Stream:

    Can be part of a fire test. After the allotted burn time, the door must with-stand the pressure of the water from a 3" fire hose being sprayed back and forth across it. Top >>
  • Intumescent:

    A special fire material which, when exposed to heat, swells to many times its original size and helps to seal closed a fire door assembly. Available in soft puff and hard puff (a description of its character after swelling), it is required for all positive pressure fire door assemblies. Classified as either Category A (concealed inside the door) or Category B (provided with the door frame). Top >>
  • Invisible Hinge:

    A hinge which is completely concealed when the door is closed. There are no knuckles visible on either side of the door. The most commonly known hinge of this type is manufactured by Soss and is often called the Soss hinge. Top >>
  • Jamb:

    The frame in which a door is hung, consisting of two legs, a butt leg which is prepared for hinges, a strike leg which is prepared for a lock bolt plate and a header, the overhead section. Jambs can be flat stock with stop applied or 1-1/4" thick and rabbeted. Top >>
  • Joint:

    The line of juncture between edges or ends of two adjacent sheets of veneer. An open joint means the adjacent sheets do not meet tightly. Top >>
  • Kerf:

    A saw cut only part way through a material. Kerfed exterior jambs have a cut part way into the jamb for a weatherstrip to be slotted in. The width of a saw cut. A back kerf is cutting slots in the back of a piece of wood to allow the face side to be bent into an arc without breaking. Top >>
  • Kickplate:

    A plate applied to the face of the lower rail of a door or sidelight to protect against abrasion or impact loads. Top >>
  • Kiln Dried:

    Lumber dried in a closed chamber in which the removal of moisture is controlled by artificial heat and usually with relative humidity. Top >>
  • Knife Marks:

    Fine lines appearing across the veneer that result from a defect in the slicing knife. These lines cannot be sanded out. Top >>
  • Knockdown System:

    Commonly abbreviated "KD”. Machined residential doors are combined with machined jambs to match in a shrink-wrapped package complete with hinges. Shipped disassembled for assembly at the building site. Top >>
  • Knot:

    Cross section of a tree branch with grain running at right angles to the piece of wood in which it occurs.
    Dead or Open Knot - openings where a portion of the wood which made up the knot has dropped out or where cross checks have occurred to present an opening.

    Pin Knot - a small sound knot 1/4" or less in diameter. A blending pin knot is a small knot which does not contain a dark center. Blending pin knots are not detectable from 6 - 8 feet away.

    Sound Knot - solid across their face and fixed by growth to retain their place.

    Top >>
  • Knuckle:

    The part of the hinge visible when a door is closed through which the pin fits. Top >>
  • Lap:

    A condition where the pieces of veneer are positioned so that one piece overlaps the other and does not make a smooth, even joint. Top >>
  • Leading Edge:

    The vertical edge of a swing door which is opposite the hinge edge Top >>
  • Lite:

    Any opening cut into a door, transom, or sidelight other than hardware cut-outs. These include window, louver, and viewers openings, and may be open only, open and beaded, or glazed. Top >>
  • Lock Block:

    A concealed block adjacent to the stile at a location corresponding to the lock location into which hardware is to be fitted. Top >>
  • Loose Lay:

    All parts of a door core are purchased pre-sanded to specific thickness and brought to the lay-up line where the parts are put through the glue spreader and laid between skins. The skin is glued to the parts in this process and actually hold the door together. Individual core parts are not bonded together. Top >>
  • Louver:

    An insert with parallel slanted sides to allow ventilation but excludes light or provides privacy. Metal, heat activated self-closing louvers are allowed in mineral core fire doors, but not in 20 minute rated fire doors because 20 min. doors are also smoke doors, and louvers do not stop smoke from passing through. Top >>
  • Matching Edge:

    The edge of the door is made from the same wood as the face. This may be an edge band or a full stile. If a full stile it is called a matching vertical edge (MVE) or matching edge stile (MES). Top >>
  • MDF:

    Medium Density Fiberboard. A generic name for material made in panel form from lignocellulosic fibers combined with a synthetic resin and bonded together under heat and pressure in a hot press by a process in which the entire bond is created by the synthetic resin. Cut and used as stiles and rails or used in sheets as door faces. Top >>
  • MDO:

    Medium Density Overlay - a thermosetting resin impregnated paper applied to a plywood to provide an optimum painting surface. Used as a doorskin. Top >>
  • Meeting Stile:

    The vertical edge of a door, in a pair of doors, which is adjacent to the other door. Top >>
  • Metal Edge:

    A piece of U-formed metal which goes over a door edge for protection. It may be to protect against impact as in hospitals where they are applied to protect against wheelchairs or hospital beds bumping them, or it may be part of a paired fire door assembly where it is used in conjunction with a fire rated astragal. Top >>
  • Metal Vision Panel:

    A metal frame used to install glass in fire rated doors. The glass must also be fire tested. Wired glass is the most common type, but ceramic glass is also used. Top >>
  • Mineral Core:

    Fire rated material made from a mixture of gypsum, cement and other minerals which will withstand temperatures hot enough to melt glass. Used by Lynden Door in our 45, 60 and 90 minute doors. Top >>
  • Mineral Streak:

    Olive and/or greenish-black streaks believed to designate areas of abnormal concentration of mineral matter in birch, maple, hickory and basswood. Also called mineral stain. Top >>
  • Miter:

    The intersection of two pieces of molding forming an angle. This angle is usually 90o and is the type of joint used for beading for insertion into a lite and is also the joint used to join casing around a door jamb. Top >>
  • Moisture Content:

    Wood naturally contains moisture. Improper or uneven drying is the single greatest cause of warp in wood products. Moisture content is the percent of moisture remaining in the wood. For door parts, recommended moisture content is 8 - 12%. Top >>
  • Mortise Lock:

    A lock which is fitted into the edge of the door into a "pocket" with a few holes drilled through the face for the passage of door knobs, key access, etc. This pocket is usually 6" long and is covered by a face plate which is routed over the pocket for a length of 8". This is often called an 86 pocket. Top >>
  • Mullion:

    A vertical member of the door frame (jamb) used to separate door leaves (or glass panels in a door) and/or sidelites. Bars are horizontal members. Top >>
  • Muntin:

    A member dividing a sash or door into smaller openings. Top >>
  • Negative Pressure:

    A type of fire test where the hot air is exhausted at the top back of the oven drawing heat away from the top of the door. Also called neutral pressure. Top >>
  • Number 1 Edge:

    A five ply door where only the face veneers are carried through to the edge of door. Coupled with a matching edge, it looks as if the veneer wraps around the door Top >>
  • Number 2 Edge:

    A five ply door with a two ply skin on each side which shows on the edge of the door. Top >>
  • Number 3 Edge:

    A seven ply door with a three ply skin on each side which shows on the edge of the door. This is the door Lynden Door manufactures. Top >>
  • Number 4 Edge:

    A door which has had a matching hardwood edge glued to the side of a number 2 or 3 edge door. This hardwood edge shows on the faces of the door and is therefore used very rarely. Top >>
  • Open & Beaded:

    An open cutout with beading cut to fit for installation of glass at a later time. Top >>
  • Overhead Stop:

    A device designed to stop a door swing at a specific angle (i.e. 90°, 110°, etc.) to keep the door from hitting a wall, tabletop, etc. It can be either surface mounted or concealed. Top >>
  • Oxalic Acid:

    A crystalline acid which, when mixed with water makes a wash for oak veneers to remove blue staining. Top >>
  • Paint Grade:

    A door skins which is smooth and even. It may have repairs or patches as long as they are tight and solid and sanded smooth for opaque finish. Top >>
  • Pair:

    Two doors hung in a single jamb. Usually these doors will be made with pair matched doorskins. They are usually machined so that one door is “active” (opens and closes the most) and one door is “inactive” (anchored) which has a strike for the active door’s lock bolt. The inactive door usually is anchored by a top and bottom rod exit device or by flush-bolts. Top >>
  • Pair Matched:

    Pairs of doors with the same grain pattern as they are made using skins manufactured from the same veneer flitch. Top >>
  • Palusol:

    A rigid intumescent typically laminated under the wood stiles in a fire door to help achieve positive pressure. Top >>
  • Particle Board:

    The standard core type in solid core flush doors made of very small pieces of wood bonded together into a slab. Top >>
  • Pitch:

    Accumulation of resin in wood. Also called Gum. Top >>
  • Pitch Pocket:

    Well defined openings between rings of annual growth containing pitch or evidence of prior pitch accumulations. Also called Gum pockets. Top >>
  • Pitch Spots:

    Pitch or resinous material of color spots caused by prior resin accumulations sometimes found on panel surfaces. Also called Gum spots. Top >>
  • Pith:

    The middle of a log, which is composed of heartwood. It is the center around which growth takes place and does not function after the sapling stage. Top >>
  • Pivot Hinge:

    Special heavy duty hinges which support greater weight than normal hinges. The top hinge is different than the middle hinge, which is different than the bottom hinge requiring separate machining set-ups for each Top >>
  • Plain Sliced:

    Veneer sliced parallel to the pith of the log and approximately tangent to the growth rings. Plain sliced veneer can be cut using either a horizontal or a vertical slicing machine or by the half round method using a rotary lathe. Also called Flat Sliced, Plain Cut, or Flat Cut. This is the most common method of cutting expensive veneers. Top >>
  • Plastic Laminate:

    Also known as P-Lam. A paper with a design or color in a high density plastic with varying types of finish which can be used as a door face. This is principally used in medical facilities as it is easy to keep clean. Also called High Pressure Decorative Laminate. Common brands are Nevamar, Wilsonart, Formica, Pionite and Arborite. Top >>
  • Pleasing Match:

    A face containing components which provide a pleasing overall appearance. The grains do not need to match at the joints but sharp color contrasts are not allowed. Top >>
  • Plumb:

    Perfectly vertical. Top >>
  • Plume:

    Figure due to crotch in Mahogany. Top >>
  • Ply:

    The layers in a sheet of plywood, door skin or door. In a door it consists of the number of plies in each skin plus the core. A 7 ply door would have two pieces of 3 ply doorskins plus the core layer. Top >>
  • Pocket Door:

    A door which has been hung in a frame which is partially in a wall so that to open the door you slide it sideways into the "wall pocket". Top >>
  • Positive Pressure:

    A type of fire test where the hot gases are exhausted from the top front of the oven, exerting outward pressure at the top of the assembly. Top >>
  • Pre-fitting:

    Reducing the width of a door to allow for better fit into a jamb. Standard pre-fit size is -3/16” off book. Top >>
  • Pre-hanging:

    The process of installing a door by application of hinges and hardware in a jamb unit prior to shipment to a job site so the entire door/jamb assembly with hardware attached can be installed at once. Top >>
  • Pull:

    A piece of hardware used to pull a door in specific direction. Examples are Bifold knobs, Flush bypass pulls inserted into cutouts in the doors and Pocket pulls (which may have latch of some kind) cut into the edge of a door. Top >>
  • Quarter Sliced:

    Veneer produced by cutting in a radial direction to the pith to achieve a straight vertical grain pattern. In some species, principally oak, ray fleck is produced, the amount of which is unlimited. Top >>
  • Rabbett:

    A longitudinal recess cut into the edge of a door. This is the usual joint in door and transom assemblies and is also used in Dutch doors. Also called Rebate. Top >>
  • Raceway:

    A groove routed through or a hole drilled through a door for the passage of electrical wires for the activation of electrical hardware. Top >>
  • Radius Edge:

    A rounded edge on the stile or stiles of a door to allow double swinging in double-acting openings. Both face sides of the door are radiused. Top >>
  • Rails:

    The top and bottom cross members of the door core frame. Also applies to any other horizontal member in the core. Top >>
  • Random Match:

    A misnomer - actually means that the pieces of veneer in a face are mis-matched to give the appearance of boards glued together. Top >>
  • Ray:

    A strand of tissue extending in a radial direction across the grain. It is oriented so that the surface is exposed in fleck across the quartered surface. Top >>
  • Relative Humidity:

    The ratio of the quantity of water vapor actually present to the amount present in a saturated atmosphere at a given temperature, expressed as percentage. Doors and their components should be about 8 - 12%. Top >>
  • Rift Cut:

    A parallel grain pattern produced by cutting at a slight angle to the radial to give an appearance similar to quarter cutting without the fleck. Used in oak veneers only. Top >>
  • Roller Latch:

    A small spring roller which is inset into the top of a door which pops up into a strike set in the jamb header, holding the door closed against a light push, but which allows the door to open with a stronger push. Top >>
  • Rotary Cut:

    A wild grain pattern results from this method of veneer slicing. A whole log is placed in a rotary lathe and as the knife is moved toward the pith of the rotating log a long continuous peel of veneer comes off. Top >>
  • Rough Opening:

    The structural framework which surrounds the wall opening for the door assembly to be anchored into. Consists of header, studs and sub-sill (which may be the floor). Also the measurement of the size of the wall opening into which the door assembly is to be positioned. Top >>
  • Rout:

    Cut or channel out wood with a tool Top >>
  • Router:

    A tool for routing. In today's parlance, the tool is usually a hand held power tool with a high speed rotating bit with a carved surface, usually of carbide steel, which, while it is spinning, is moved along a piece of wood causing the wood to be molded to the shape of the cutting bit. Top >>
  • Sanding:

    Taking an abrasive paper, literally a heavy paper with sand of various grits glued to its surface, and rubbing it against a piece of wood or veneer to remove rough spots or handling marks. The higher the number grit, the finer the sandpaper. Sandpaper is measured by grit pieces per inch. A 40 grit sandpaper will have 40 pieces of grit per inch. To fill the paper, each piece of grit will have to be large, giving a very rough, coarse surface. This is used for preliminary sanding where removing uneven surfaces is desired. A 400 grit sandpaper will have 400 pieces of grit per inch, so each piece will be very small to fit on the paper. This surface will be almost smooth and will be used for finish sanding, almost polishing the wood. Top >>
  • Sapwood:

    The living outer wood of the tree. Usually a lighter color than the heartwood Top >>
  • Sealing:

    Applying a coating to a door which makes it impervious to moisture and thus reduces the chance of it warping or telegraphing. Top >>
  • Semi Solid:

    A hollow core door with 4" particle board strips inside both stiles and across the top rail, with an 8" strip at the bottom rail for added strength & stability. Top >>
  • Sequence Match:

    Matching of several doors by using veneer from the same flitch in all of them in an ordered pattern. Also called Set Matching and Blue Printing. Top >>
  • Shake:

    A separation along the grain of wood in which the greater part occurs between the rings of annual growth. Top >>
  • Shims:

    Small pieces of veneer from the same piece of veneer or at least another piece of same color and grain pattern used to repair an open joint. After being glued into the split and sanded, the shim should be inconspicuous to the naked eye. Top >>
  • Sidelight:

    A panel beside a door in an entry system. These are decorative and may be of wood or glass. Usually part of the front entrance to a home. Top >>
  • Sill:

    The bottom horizontal member of a door or window Top >>
  • Slip Match:

    Adjoining pieces of veneer are placed in sequence without turning over every other piece. The grain figure repeats, but the joints do not have a mirror image. Slip matching is often used in Rift or Quarter cut veneers to eliminate the barber pole effect. Slip matching may cause a sloping or banana or bending appearance in the veneer, especially in taller doors. Top >>
  • Smoke Seal:

    A gasketing material which is designed to prevent smoke from leaking through a fire door/frame assembly during a fire. Top >>
  • Softwood:

    Woods from coniferous or needle leaved trees (Gymnosperms). The term does not denote the texture of the wood, as softwoods are often harder than hardwoods. Examples are fir, spruce, pine and hemlock. These are often used to make stiles and rails for doors Top >>
  • Softwood Edge:

    The term used when requesting a softwood be used for the stiles of a door. Top >>
  • Sound Transmission:

    Also called STC doors - a method of rating doors for the amount of noise which transmits through the closed door. Top >>
  • Split:

    A separation along the grain, forming a crack that extends through the veneer allowing you to see the cross-band. Top >>
  • Square:

    In doors, being “square” means that the top and bottom widths are equal. The lengths of the door on each side are also equal, with all four corners at right angles. If a door is measured from top right corner to bottom left and from top left to bottom right and the measurement is the same the door should be square. Top >>
  • Stave Lumber Core:

    Made by gluing blocks or strips of wood, not more than 2 ½" wide, of one species with a moisture content of 6 - 9%. Joints must be tight and must be staggered in adjacent rows. Abbreviated as SLC. Also called wood core or lumber core. Top >>
  • Stile & Rail:

    Doors made up of solid wood stiles and rails assembled around panels. Also known as panel doors. This is the way doors were made historically before flush doors were invented. Top >>
  • Stiles:

    The vertical edge of the door. Stiles may be fiberboard, fingerjoint, hardwood or softwood. Top >>
  • Strike:

    The leg of the door jamb or frame against which the lock side of the door swings. It is also the metal plate set into the strike leg of the jamb which catches the lock bolt to hold a door closed. Top >>
  • Structural Composite Lumber:

    Also known as glulam (glued laminated timer), it is an engineered lumber product made with 1" wide wood strands, bonded with Type 1 adhesives. It swells less than typical hardwoods or softwoods and is therefore superior to other solid cores as it minimizes telegraphing, warping or splitting. Abbreviated as SCL. Core, rails, and stiles for plastic laminates are often made from this material. Weyerhaeuser produces a laminated strand lumber product they call TimberStrand® within this category. Laminated veneer lumber is another type of engineered wood product that falls within this classification. Top >>
  • Substrate:

    Material on which glue is spread such as door core or the center plys in plywood. Top >>
  • Telegraphing:

    The outline (and/or surface irregularities) of frame parts, core laps or voids, etc. that is visible through the face of the door. This is usually caused by differing moisture content in the separate core parts at lay-up time. Also called show-through. Top >>
  • Temperature Rise:

    During a fire test for 60 minute or higher rated doors, thermometers placed on the outside of the door register the rise in temperature for thirty minutes. The temperature of wood door may not rise to more than 250o F during this time. A metal door may not rise more than 450o F in the thirty minutes. Top >>
  • Tempered:

    Treatment with heat to increase hardness. This is normally a term used in metal working and glasswork, but some hardboards are tempered as well. Top >>
  • Textured:

    Refers to the visual or tactile surface of a door skins. This indicates that an artificial grain pattern has been embossed into the skin. Top >>
  • Threshold:

    The tread member of an entrance, a sill. Top >>
  • Through Bolts:

    Hardware bolts which pass totally through a door and anchor on the back. Top >>
  • Track & Hardware:

    The overhead track which a bifold moves and the hardware which installs it come included in every bifold Lynden Door sells. Heavy duty track and hardware is recommended for all solid core bifolds. Top >>
  • Transom:

    A window or panel above a door. It may be within a separate frame and may be hinged to open, allowing air passage (usually in older buildings before air conditioning). Top >>
  • Trim:

    The finishing components, such as molding, which are applied around openings (doors frames) or at the floor and/or ceiling of rooms. They may also be applied to doors as plant-ons. The term also refers to the sizing of doors to their finished specific size with smoothly finished edges and easing of the faces. Top >>
  • Trim Hole:

    A hole drilled into the face of the door to allow for the application of hardware decorative trim at a later time. Top >>
  • Ultraviolet Finish:

    A means to dry certain special kinds of paint almost instantly. Lynden uses this process on its bifold edge finishes. The finish is applied by rollers, then passed through an Ultraviolet drying oven which dries the finish as fast as the bifolds pass through the booth. Because of the possible hazard of continuous UV illumination to the eyes and skins, the drying oven is completely enclosed in a protective booth. Top >>
  • Undercutting:

    Reducing the height of a door to allow for better clearance between finished flooring or carpeting and the bottom of door. Top >>
  • Universal Building Code:

    The set of regulations governing building and construction in North America. This code regulates fire door assemblies as well as other construction details. Top >>
  • Veneer:

    A thin layer or sheet of wood cut to uniform thickness. Top >>
  • Viewer:

    A special piece of hardware placed into a door which allows the person inside to view outside the door without opening the door. Viewers are normally one way only, and cannot be used by a person standing outside the door. Top >>
  • Vine Marks:

    Scars in the wood normally caused by the stems of clinging vines or by their hair-like roots which cling to the trees. Live vine streaks produce sound scars. Dead vine streaks contain either dead residue of the vine or the remaining pocket, similar to a bark pocket. Most vine streaks run across the grain. All vine streaks are considered defects. Top >>
  • Ving Card Lock:

    The most common type of electronic lock currently in use Top >>
  • Warp:

    Any distortion in the plane of a wood door itself and not in its relation to the jamb in which it is hung. Warp includes the following:

    Bow – A flatwise deviation from a straight line drawn from top to bottom; a curvature along the length of the door.

    Cup – A deviation from a straight line drawn from side to side; a curvature along the width of the door.

    Twist – A deviation in which one or two corners of the door are out of plane with the other corners of the door.

    Top >>
  • Weatherstrip:

    Insulating material which is put around a door to prevent drafts and heat loss. Top >>
  • Wicket:

    A small door within a larger door. Top >>
  • Wicket Door:

    A standard size door with a small door in it. This small door can be opened and allow small articles to be passed through it without a person being able to go through. These doors are often used in post offices. They have usually been replaced by dutch doors. Top >>
  • Worm Hole:

    A hole resulting from the boring of a worm. Hole is greater than 1/16" in diameter but less than 5/8" in length. Top >>
  • Worm Track:

    The groove or resulting scar tissue in the wood caused by worms or other borers. Also called Worm Scar. Top >>
  • Zebrawood:

    A very hard, heavy wood, strong and durable with wide variegated bands. Top >>