Backcheck An optional feature in hydraulic door closers, which takes effect at a certain degree of opening and controls the speed of the door during the balance of its opening cycle.
Backset The horizontal distance from the face of the lock to the centre line of the cylinder, key hole or knob hub.
Ball-Bearing Hinge See Hinge.
Barrel Key A key with a round shank and wing bit. The shank has a hole in the end, which is inserted in the lock. Used chiefly for cabinet locks.
Barrel a) A tubular portion of the cylinder which rotates when the correct key is used.
b) That portion of a hinge that is enlarged to receive the pin and act as the pivot point. It includes one or more knuckles from each individual leaf
Basement The lowest story of a building, partially or entirely below ground.
Batten A strip of board for use in fastening other boards together.
Beam A horizontal structural member that carries a load.
Bearing Partition A partition supporting any vertical load in addition to its own weight.
Benchmark A reference point used by surveyors to establish lines and grades.
Bevel Angle of the striking face of a latchbolt.
Bevelled Faceplate A faceplate shaped to fit the closing edge of a door which is not at 90 degrees to the face of the door.
Bitted Key Generally means a cut key. In lever locks, it means a key with the blade projecting at right angles from the shank.
Bitting A number that represents a depth of a cut on a pin tumbler-type key. A bitting is often expressed as a series ofnumbers and/or letters that designate all the cuts on a key.
Bolt The part of the lock or latch that projects to engage the strike or staple.
Bolt Projection The projection of a bolt frocrnthe faceplate when fully extended.
Bolt Throw The distance the bolt travels when it is extended.
Box Strike A strike in which the bolt recess is enclosed or boxed, thus covering the opening in the jamb.
Bright Finish A term used to describe builders’ hardware that is polished and buffed.
Broach The aperture into which the key is inserted.
Broad Butt Hinge A wider version of the butt hinge.
Budget Lock A lock usually operated by a square shape key, offering very little security.
Buffing The process of providing a lustrous finish by means of power-operated soft fabric wheels coated with a wax compound containing fine, abrasive particles.
Burnishing The process of developing a smooth, lustrous surface on metal parts by tumbling in a drum with small steel balls or by rubbing with hard metal pads.
Butt Hinge (or Butt) See Hinge.
Butt Weld A weld of members butting against each other.
Button-in-Knob An inside knob with a built-in button that controls the locking and unlocking of the outside knob. May be either push button or turn button.
