Areas of fiber from outside a tree.

Machine angle other than a right angle. That is, a 3-degree bevel which is equivalent to a 1/8-in. drop in a 2-in. span.

Beveled edge:
Edge of a door which forms an angle of less than 90 degrees with the wide face of the door, such as a 3-degree beveled edge.

Spot or area where veneer does not adhere.

Book size:
The height and width of a door before prefitting.

Condition of wood characterized by low resistance to shock and by abrupt failure across the grain without splintering.

Swirl or twist in grain of wood, which usually occurs near a knot but does not contain a knot.

Butt joint:
Joint formed by square edge surfaces (ends, edges, faces) coming together.

White or other color chalk marks used by mills for some form of identification marking defects for repair.

Lines appearing across the panel at right angles to the grain giving the appearance of one or more corrugations resulting from bad setting of sanding equipment.

Chicken tracks:
Expression for scars which give the particular effect of a chicken’s footprint. It is caused by air roots or vines.

When a defect described in the grading rule is sufficient in number and sufficiently close together to appear to be concentrated in one area.

Composition face panels:
A door face panel made of a wood derivative.

Innermost layer of section in flush door construction. Types of construction include: wood block; particleboard; wood block (lined); hollow; ladder; mesh or cellular.

Core (Wood Block):
Solid core of wood blocks or strips

Core (Particleboard):
Sold core of wood or other lignocellulose particles bonded together, cured under heat, and pressed into a rigid panel.

Core (Wood Block, Lined):
Solid core of two parts: a central wood block core bonded to two core liners of wood or other lignocellulose materials.

Core (Hollow):
Core assembly of strips or other units of wood, wood derivative, or insulation board, with intervening hollow cells or spaces which support outer faces.

Core (Ladder):
Hollow core composed of strips of wood, wood derivative, or insulation board with the strips running either horizontally or vertically throughout the core area with air cells and/or spaces between the strips and supporting the door faces.

Core (Mesh or Cellular):
Hollow core composed of strips of wood, wood derivative, or insulation board, interlocked and running horizontally, vertically, or diagonally throughout the core area with air cells and/or spaces betwe en the strips and supporting the outer faces.

Veneer placed between the core and face veneers of plywood face panels of wood flush doors in which the direction of the grain in 2-ply construction is at right angles to that of the face veneer.

Cross bar:
Type of figure or irregularity of grain resembling a dip in the grain, running at right angles, or nearly so, to the length of the veneer.

Cross break:
Separation of wood cells across the grain.

Dead knots (also open knots):
Openings where a portion of the wood substance of the knot has dropped out, or where cross checks have occurred to present an opening.

Separation of plies or layers of wood or other materials through failure at an adhesive joint.

Stains in wood substances. Common are sap stains and blue stains.

Form of incipient decay characterized by a dull and lifeless appearance of the wood, accompanied by a lack of strength and a softening of the wood substance.

Edge band:
Strip along the outside edges of the two sides and/or top and bottom of a door.

Face panels:
Hardwood plywood, high pressure laminate, hardboard, or composition panels or combination thereof, whether flat or configured, which are used for the faces of flush doors.

Fill (putty repairs):
Repair to an open defect with fast-drying plastic putty.

Finger joint:
Series of interlocking fingers cut on the ends of two pieces of wood which mesh together and are held by adhesive.

Open splits in the inner ply or plies, or improperly joined veneer when joined veneers are used for inner plies.

Gum spots:
Well-defined openings between rings of annual growth, usually containing gum or pitch.

Lumber dried in a closed chamber in which the removal of moisture is controlled by artificial heat and usually by relative humidity.

Knife marks:
Very fine lines that appear across a panel that may look as if they are raised resulting from some defect.

Knot (sound):
Cross section of a branch or limb with grain usually running at right angles to that of the wood in which it occurs.

Knot holes:
Voids produced by knots dropping from the wood in which they were originally embedded.

Knots (pin):
Sound knots less than 1/4-in. in diameter.

Condition where veneers composing plywood are so misplaced that one piece overlaps the other and does not make a smooth joint.

Lock block:
Concealed block same thickness as a door stile or core which is adjacent to the inside edge of the stile at the midpoint and into which a lock is fitted.

Matching wood pieces carefully inserted and glued into the door face after defective portions have been removed.

Bleeding resin.

Cross or horizontal pieces of the framework of a wood flush door

Rail (bottom):
Bottom cross or horizontal piece of a door.

Rail (top):
Top cross or horizontal piece of a door.

Separation along the grain, the greater part of which occurs between the rings of annual growth.

A split repaired in a piece of wood veneer.

Irregular surfaces visible on the face of a wood flush door.

Standard door:
By industry practice, a standard door is book size in both width and height.

Upright or vertical pieces of the framework of a wood flush door.

Strips of gummed paper used to hold edges of veneer together at the joints before gluing.

Visible irregularities in surface of face of plywood caused by corresponding irregularities in the underlaying plies such as core laps, voids, or extraneous matter.

Types (door styles):
The selection includes exterior entrance doors, interior passage doors, French or casement doors, bi-fold doors, side lights, patio sliding and swinging doors, thermal insulated-glass doors, louver do ors, screen doors, and specialty door products. Several selected types are illustrated here.

Vine streaks (marks):
Scars in wood generally caused by the stems of vines clinging by their hair-like roots to the tree trunk.

Any distortion in the plane of a door itself and not its relationship to the frame or jamb in which it is to be hung. Warp includes bow, cup, and twist:

  • Bow: A flatwise deviation from a straight line drawn from top to bottom; a curvature along the width of the door.
  • Cup: A deviation from a straight line drawn from side-to-side; a curvature along the width of a door.
  • Twist: A deviation in which one or two corners of a door are out of plane with the other corners of the door.

Wood flush door:
Stressed skin construction consisting of a core, stiles, and rails, and or/edge banding, two face panels, almost all of which are wood, wood derivative. materials, or high pressure decorative laminate.

Worm track or scar:
Groove or resulting scar tissue in wood caused by worms or other borers.