Glossary of Garage Door Terminology

Table of Contents

3-Hole Adjustable Clip

See 3-Hole Cable Clip
3-Hole Cable Clip
Metal clip tied to end of extension spring cable to allow length adjustment
3-Hole Cable Connector
See 3-Hole Cable Clip


Accent Moulding
Half-round and square mouldings that provide a distinctive mode of expression to doors
Access Door
See Pass Door
Active Coils
The number of working coils in a torsion spring
Adjustable Cone
See Winding Plug
Adjustable Sleeve
See Winding Plug
Adjusting Rod
See Winding Rod
Adjusting Spring Cone
See Winding Plug
Aero Cable
See Aircraft-Type Cable
Support member used to fasten torsion spring assembly of a vertical lift door to the wall above the door opening
Air Infiltration
The leakage or passage of air through a door system
Aircraft Cable
See Aircraft-Type Cable
Aircraft-Type Cable
Several strands of galvanized wire rope braided together
Anchor Cone
See Stationary Cone
Anchor Plug
See Stationary Cone
Angle Brace
Lateral brace attached to back hang and roof construction or ceiling
Angle Iron
Length of L-shaped steel material generally used to support and brace rear of horizontal tracks from roof construction or ceiling
Angle Mounted Track
A method of fastening vertical track to a door jamb using a full height continuous angle
A hard non-corrosive oxide film on the surface of aluminum
See Bottom Weatherseal
Astragal Floor Rail
See Bottom Weatherseal
Astragal Retainer
See Bottom Weatherseal
Automatic Latch
An automatic door locking device
Automatic Opening Device
Quick opening mechanism recommended for installations requiring rapid automatic door opening without use of an electric operator


Back Hang
Hanger fabricated from angle iron, which attaches the end of the horizontal tracks to roof construction or ceiling
Back Jamb
Wood member on the inside surface of the garage, surrounding the door opening
Horizontal distance measured into a building from the face of the header above a garage door opening to the first obstruction at the required headroom
Ball Bearing
A load bearing device that uses trapped rolling balls to reduce rotating friction
Ball Bearing Drum
Counterbalance drum with a ball bearing for smoother operation of heavier doors
Bar Joist
A lightweight truss adaptable for the support of roof decks
A strip of metal, vinyl, or rubber used to secure glass around the periphery of a pane
Color-marking convention to mark parts as Right Side, Left Wound
Blind Rivet
A type of fastener that mechanically joins two pieces of material together by means of a riveting tool
Booster Spring
Additional spring, usually an extension spring, provided to compensate for weakened counterbalance
Bottom Bracket
See Bottom Corner Bracket
Bottom Corner Bracket
A structural support located on the bottom section that holds track rollers and may also provide for attachment of lifting cables
Bottom Corner Fixture
See Bottom Corner Bracket
Bottom Fixture
See Bottom Corner Bracket
Bottom Rail
The lower-most horizontal rail of a door section
Bottom Roller Bracket
See Bottom Corner Bracket
Bottom Weatherseal
Weatherstrip attached to the bottom rail of a door to seal against the floor
Condition where a garage door bottom rail of a wood door is not level or straight, which is characterized by a closed door “smiling” (corners turned up)
Box Strut
See Strut
Bracket Mounted
Method of fastening vertical track to jamb using angle brackets
Bracket-Mounted Track
See Bracket Mounted
Breakaway Track
See Angle Mounted Track
Breakstem Rivet
See Pop Rivet
Broken Cable Device
A bottom fixture intended to prevent a door from falling in the event of cable breakage
See Back Jamb
A fixed or removable lining used to constrain, guide, or reduce friction


See Aircraft-Type Cable
Cable Clamp
Manufactured device used to secure two pieces of cable to each other
Cable Drum
Grooved drum, fitted on torsion spring shaft, onto which lifting cable is wound when door is opened
Cable Drum Set Screws
Normally refer to set screws that attach the drum to the shaft/tube. One screw may secure the cable to the drum in order to secure proper cable length.
Cable Length
Specific amount of cable required to properly operate door
Cable Safety Device
A bottom fixture designed to slow or stop the descent of a door in the event of a cable breakage
Cable Stop
A swaged fitting at the end of the cable to prevent slippage through a slot in a drum
Cable Stopping Device
See Broken Cable Device
Rotating piece that transfers rotary motion into linear motion
Cam Tube
Tube encasing a torsion spring assembly that imparts axial force
Carry-Away Post
A type of removable center post
Top horizontal surface in the interior of a garage
Center Bearing Bracket
A bracket that houses a shaft bearing and aligns and supports the torsion shaft and spring(s) assembly. Also serves to anchor stationary cone(s) to header
Center Bearing Plate
A plate or bracket that can house a shaft bearing and is used to align and support the counterbalancing mechanism to the torsion shaft as well as anchor one end of torsion springs to the header.
Center Bearing Support
See Center Bearing Bracket
Center Bracket
See Center Bearing Plate
Center Bushing
Metal or plastic bushing used with a center bracket to support a torsion tube
Center Cable
See Center Lift Cable
Center Clamp
See Center Lift Cable
Center Coupler
See Coupler
Center Coupling
See Coupler
Center Hinge
A hinge generally located on the intermediate stiles to allow sections to pivot as door opens. Also used as graduated edge hinge between bottom and intermediate section
Center Lift Cable
Additional cable assembly which is secured to outside of door at points toward the center of the door, used to provide extra lifting support for extremely wide or heavy doors.
Center Post
The vertical building structure (or member) between two single car doors, or a vertical reinforcement usually installed for high wind events. Sometimes also used to refer to a Vertical Post.
Center Stile
Vertical member of a door section which provides structural rigidity and location for center hinge attachment
Center Support Bearing
See Center Bearing Bracket
Center Support Track
See Center Track
Center Track
Added track giving additional support to preventing sagging of a door in the open or horizontal position. Often used with an exceptionally wide door, a heavy door or a door containing a pass door
Chain Hoist
Refers to sprocket or pocket wheel, connected to torsion spring shaft, imparting mechanical advantage to open and close a door
Chain Hoist Operator
Jackshaft type operator to which chain hoist is attached
Channel Frame
Frame used in jamb construction consisting of steel channel shapes installed where the flanges of the shapes wrap around the corners of jambs
Channel Truss
See Strut
A square shaft that connects an outside handle to an inside lock set or night latch
The amount of side room, head room and back room required to properly install a sectional door
See Sheave Fork
Clevis Pin
A steel pin used in conjunction with a cotter pin to hold a counterbalance cable to a bottom bracket or an operator arm to an operator bracket
A sectional overhead type door which is intended for vehicular use at entrances of buildings such as loading docks and service stations, and is normally operated less than 5,000 cycles per year
Containment Cable
A cable threaded through an extension spring to retain the spring if it breaks
Continuous Angle
See Reverse Angle Mount
Continuous Angle Mount
See Angle Mounted Track
Contour Track
Horizontal track that follows the contour of roof construction or ceiling
Corner Bracket
See Bottom Corner Bracket
Corner Burn
A full-scale fire test performed in a specially constructed room, where the ignition source is located in the corner of that room, adjacent to the garage door
Cotter Pin
A half-round metal strip bent into a pin, whose ends can be flared after insertion through a slot or hole
To oppose or balance with an equal weight or force
Counterbalance Shaft
See Torsion Shaft
Counterbalance System
A system which counteracts the weight of a garage door to allow a reduced force to open and close the door
Counterbalance Tension
See Counterbalance
Design of door mechanisms using weights instead of springs to counterbalance door weight
Counterweight Balancing System
See Counterweight
A device to connect two counterbalance shafts together, end-to-end
See Coupler
“C” Strut
See Strut
Heat rate flow through an insulating material when there is a temperature difference from outer to inner surfaces; not normally used in conjunction with thermal transmittance through garage doors
One complete cycle of a door beginning with the door in the closed position, then moving to the open position and back to the closed position
The part of a key operated lock that accepts the key and contains the locking pins


Daylight Opening
Opening dimensions taken between face of jambs and between floor and header
Door opening size designation, denoting “double car”
Dead Coils
The number of coils rendered inactive by the spring plugs
Dead-End Cone
See Stationary Cone
Dead in the Head
The lack of counterbalancing when the door is in the open position, failing to keep the door fully open
Dead Load
A static applied load, or a load without movement, generally referring to the weight of the door
A template of information attached to a garage door, or in its vicinity, to convey relevant information concerning the garage door system
Decorator Angle
See Jamb Angle
See Backroom
Design Wind Load
Horizontal design load applied to a garage door based on such factors as wind speed, building height and door horizontal location
Direct Drive Chain Hoist
See Chain Hoist
Disconnect Chain
Used in conjunction with industrial door operators to disengage operator and permit manual use of emergency hand chain to facilitate operation of door in event of power failure
Disconnect Hoist
See Disconnect Chain
Door Casing
The framing members with which a door opening is finished
Door Check
A mechanical device to insure the self closing of a pass door or wicket
Door Closer
A device, combining in one case, a spring to close the door, and a checking arrangement to prevent slamming and to insure silent closing
Door Frame
The frame into which the door fits; consists of two door jambs, and a door header
Door Framework
See Door Frame
Door Guide
See Track
Door Header
The upper part of a door frame, consisting of the head jamb, head casing, stop and trim molding
Door Jamb
The upright framing on each side of the door opening
Door Moulding
See Door Casing
Door Opener
See Electric Operator
Door Opening
See Daylight Opening
Door Operator
See Electric Operator
Door Path
See Trajectory
Door Schedule
A list of door sizes, locations and special requirements shown on a construction document
Door Section
A single segment of a sectional door
Door Size
Door dimensions characterized by the width first and the height second
Door Stop
See Stop Mould
Door Travel
See Trajectory
D Shaft
A torsion shaft manufactured with a flat area allowing minimum rotation of affixed hardware.
Double Door
Commonly used to refer to larger width doors used on two car openings
Double End Stile
When a door section utilizes two stiles adjacent to each other on each end of the section
Double Glazing
Use of two thicknesses of glazing within an opening to improve insulating value and/or reduce sound transmission
Double Low Headroom Track
See Double Track Low Headroom
Double Shaft
Double torsion spring shaft used when additional space is required to accommodate counterbalance spring lengths
Double Strength Glass
A grade of window glass lighter than plate glass and usually 1/8” thick
Double Thick Glass
See Double Strength Glass
Double Top Roller Fixture
Fixture used at the top section consisting of two top brackets to incorporate a longer roller shaft. Usually requires double end stiles on top section
Double Track Low Headroom
Addition of second pair of horizontal tracks to reduce the high point of travel of top section and permit door being mounted in area with minimum headroom facilities
Wooden pin for fastening wood usually glued in between stiles and rails to strengthen a joint
Drawbar Operator
Electric operator which mounts above the door in the horizontal position and lifts door by pulling and pushing the top section. For normal headroom and low headroom doors
Drip Cap
A projection over the head of a door opening, or on the top of a wall, to throw water clear of the building
Drip Lap
An angled weather seal provided between sections on steel doors in lieu of a rabbeted joint to prevent entrance of the elements
Driveway Post
Post mounted adjacent to a residential driveway to provide exterior location for key switch to actuate an automatic door operator.
Drop-Off Weight
See Counterweight
Acronym for Double Strength Grade B Glass
Duplex Spring
A combination of two torsion springs of different diameters telescoped within spring fittings


Eased Edge
Rounded and sanded meeting rail edge
Eased Off
See Eased Edge
Eave Height
Height measured from the floor to the underside of an eave
Edge Grain
Wood in which the rings form an angle of 45 degrees or more with the surface of the pieces
Edge Hinge
See Graduated Edge Hinge
Electric Opener
See Electric Operator
Electric Operator
An electrically-powered device to control the opening and closing of a door
Electrical Interlock
Interlock to prevent door operation by an electric operator under certain conditions
Embossed Door Section
Door section featuring embossed panels
Embossed Panel
Panel containing surfaces raised in relief from a flat surface
Embossed Rosette
Special ornament or design accessory made of wood, hardboard or aluminum with designs raised in relief from the surface
Embossed Section
See Embossed Door Section
Embossed Steel Door Section
See Embossed Door Section
End Bearing Plate
Plate commonly used on torsion spring counterbalance units, which includes a ball bearing to support radial movement of a torsion shaft at each end
End Bearing Support
See End Bearing Plate
End Bracket
See End Bearing Plate
End Hinge
See Graduated Edge Hinge
End Roller Hinge
See Graduated Edge Hinge
End Stile
Stile located at each end of a door section which provides for attachment of graduated edge hinges
End Stile Lock
See Inside Lock
End Stile Sealing Strip
Foamed plastic strip to seal sections at end stiles of steel and fiberglass doors
A plate surrounding the lock mechanism on outside of door
Exhaust Port
Opening in bottom section to accept hose to vent tailpipe exhaust
Extension Spring
Provides power or tension by stretching or pulling, and is usually mounted along the horizontal section of track extending from front of door opening to the back hang
Exterior Lock
Keyed lock on exterior of the door
Fabricated shapes made by forcing hot aluminum, or plastic, billets through a die in an extrusion press


False Louver Molding
Special angular shaped molding that gives an appearance of a slatted panel when fitted together
Metal ring or cap which is affixed to a cable by compressing so as to form a button or loop on the end of the cable
Finger Joint
Joint used in joining lumber together at ends of lumber pieces
Finish Moulding
See Stop Mould
Finished Door Opening
See Daylight Opening
Finished Opening
See Daylight Opening
Fire Station Release
See Automatic Opening Device
See Jamb Angle
Flag Angle
See Jamb Angle
Flag Bracket
See Jamb Angle
Flame Spread Index
A measurement of horizontal flame spread across a product specimen under controlled laboratory conditions; the product is compared to the performances of red oak, which is standardized to 100, and gypsum board, which is standardized to zero
See Automatic Latch
Floor Seal
See Bottom Weatherseal
Floor Step
See Rain Stop
Flush Design
See Flush Door
Flush Door
Door comprised of sections unbroken by visible rails and stiles where the facing of the entire door presents an even surface
Follow Roof-Line Hardware
See Contour Track
Follow-the-Roof Pitch
See Contour Track
Follow-the-Roof Track
See Contour Track
Front Mounted Low Headroom
Low headroom hardware where springs mount on torsion shaft above opening
Front-Mounted Spring
A counterbalance spring that is mounted to the header above the door
Full Vertical Lift
See Vertical Lift
Full View Section
Full Vision Section (A totally glazed section with various types of glass or clear plastic. Section formed of aluminum extrusions which will marry with steel or aluminum sections above and below)
Full Vision Section
See Full View Section


Zinc coating to protect steel against corrosion
Garage Door Opener
See Operator
Garage Door Operator
See Operator
U.S. Standard, established by congress in 1893, specifying that weight per square foot would be indicated by a numbering system; larger numbers indicate smaller thicknesses and vice versa
Fitted with panes of glass or clear plastic
Glazing Lite
See Vision Lite
Glazing Strip
Extruded plastic or rubber strips that fit against glazing and window frame to resist water infiltration
Graduated Edge Hinge
Hinge placed on edge of door sections allowing sections to pivot as door opens and closes. Hinges hold track roller and are graduated and numbered for correct placement to ensure flush fit of door against jambs when closed
Grease Packet
Lubricant enclosed in a small packet
Insert within a window, designed to give the appearance of divided lites
Guard Angle
See Track Guard
Cast, extruded, stamped, or rolled aluminum corner reinforcement which is fastened in corners to stiffen joints or corners
Gusset Plate
Hardware fastened to door header to help support the track assembly and spring assembly


Hang Down
The amount of the door that hangs down from the door opening when the door is in the open position
Hanging Iron
See Angle Iron
H-Column Jamb
Separation of two door openings where door track is to be mounted directly to H-Column
See Door Header
Header Seal
See Top Seal
The supporting plate for the lifting drum located in line with the outer edge of the door
Vertical clear space required inside above the door opening, and below the lowest ceiling obstruction, required for proper operation of the door and its hardware
Heliarc Weld
A type of inert gas-shielded arc welding employing helium or argon
High Arc
See Trajectory
High Cycle Spring
Counterbalance springs with increased cycle life capability for high usage doors
High Lift
Distance from header to underside of horizontal track, when high lift track is required
High Lift Drum
A cable drum contoured to balance a high lift door
High Lift Track
Track and hardware that causes the door to rise vertically some distance above the top of the door opening before it levels out into a horizontal position
High Moment Arm
Radius of a cable drum, including cable, at point of cable peel off from the drum
High Trajectory
See Trajectory
See High Lift
Hi-Lift Track
See High Lift Track
Hardware item that joins door sections together, and allows sections to pivot independent of each other
Hinge Support Plate
Plate used to support the hinge mounting area, i.e. a backup plate
Hinge Tube
Tube used to connect two hinge leafs together
Hoist Electric Operator
Similar to a jackshaft-type operator but with an auxiliary emergency chain hoist in case of a power failure
Horizontal Angle
See Horizontal Track Angle
Horizontal Radius
Section of track that transitions from vertical to horizontal track welded, bolted or riveted to the horizontal track and then bolted to the flag angle
Horizontal Reinforcing Angle
See Horizontal Track Angle
Horizontal Rise
The upward slope of the horizontal track which helps to start the door downward and helps maintain cable tension
Horizontal Track
Track used in the horizontal segment of a track assembly
Horizontal Track Angle
An “L” shaped angle affixed to the horizontal track to stiffen it
Horizontal Track Assembly
An assembly made up of horizontal track and reinforced with an angle that is used to both guide and support the door in the horizontal position
Horizontal Track Radius
See Horizontal Radius
Hot Off The Floor
Condition where the door has a tendency to lift off the floor


English unit of measurement of torque
Inclined Track
Tapered spacing of the vertical track away from the jamb, permitting weathertight closing of door against jamb and easy release for opening door by eliminating friction
Inside Hook Up
Connection where the counterbalance cable is on the inside of the track, between the door sections and the vertical track
Inside Hook Up Bottom Bracket
Bottom corner bracket where the cable is routed between the vertical track and the door sections
Inside Lock
Spring loaded, sliding deadbolt lock or spring latch operable only from interior of the door
Placing a door in position for use
Person placing the door in position for use
Insulated Door
Door sections containing insulating material
Insulating Glass
Multi-pane glass assembly containing air space between panes for insulation
Material having ability to reduce heat or cold transmission
Interior Lock
See Inside Lock
Intermediate Hinge
See Center Hinge
Acronyn for Inch-Pounds Per Turn; torque rate of a spring, indicating the number of inch-pounds of torque delivered to a shaft for each turn the spring is wound
Acronym for “inside looking out”


Jackshaft-Type Operator
Operator which is mounted on wall or ceiling, with drive provided to turn a torsion shaft
See Door Jamb
Jamb Angle
See Angle Mounted Track
Jamb Bracket
“L” shaped bracket used to connect the vertical track to the door jamb
Jamb Extension
Framing extensions of door jambs above opening height; required to support door track and spring assemblies
Jamb Guard
See Track Guard
Jamb Seal
See Stop Mould
Joint, Rabbeted
See Joint Shiplap
Joint, Shiplap
A raised back portion of a section joint, fitting with a lowered front portion of a section joint, to create a weathertight seal between door sections
Joint, Tongue-and-Groove
A joint with an interior raised portion, fitting with a joint with an interior lowered portion, to create a weathertight seal between door sections
Joint Bracket
See Splice Jamb Bracket
Joint Seal
See Section Joint Meeting Rail Seal


Keeper Plate
See Striker Plate
A square piece of steel that slides into a key way to prevent parts from rotating on a shaft
Key Alike
See Keyed-Alike
Key Switch Control
Use of key switch to actuate a door operator in place of or in addition to a push-button or transmitter
Key Way
A groove, milled into an object, which when used with a key will prevent parts from rotating on a shaft
Two or more lock cylinders intended to be opened with the same key
Keyed Shaft
A shaft that has an integrated key way
Laboratory-determined value of thermal conductance of a material


“L” Strut
See Strut
Lag Screw
A heavy wood screw with a square or hex head and a coarse thread
Lap Jamb
Condition where door sections lap the door opening on each jamb
Lapped Joint
See Joint, Shiplap
Latch Lock
See Automatic Latch
Lateral Force
Force applied from or toward the side
Lift Bracket
See Bottom Corner Bracket
Lift Clearance
See High Lift
Lift Clearance Track
See High Lift Track
Lift Handle
Handle for manually operating a sectional door
Lift Plate
See Step/Lift Plate
Beam provided over an opening to carry wall and/or roof loads over an opening
See Vision Lite
Device to secure door to vertical track(s) in the closed position
Lock Bar with Cremone
Rotating the cremone or lock bar disc from outside or inside will force lock bars into cut-outs in track to lock door
Lock-On Bottom Roller Bracket
See Bottom Corner Bracket
Lock Strike
See Striker Plate
Long-Stem Roller
Roller with a shaft length of 7 inches or longer
An opening with slats or screening for ventilation
Low Headroom Hardware
See Low Lift Hardware
Low Lift Hardware
Low headroom accessories which enable a door system to operate in minimal headroom conditions
Low Moment Arm
Smallest radius, or distance from the shaft axis, to the center of the cable that regards cable peel off point on cable drums
Acronym for left side looking out
A substance used to lubricate
To make a surface smooth or slippery; to reduce friction


The act of keeping a door system in good working condition
Master Keyed
See Master Keying
Master Keying
Arrangement whereby cylinder locks, although fitted with different keyed cylinders, can be opened or locked by means of one master key
Meeting Rail
The top horizontal rail or bottom horizontal rail of any section that meets and joins to form a weatherproof seal
Metallurgist Report
A report or document that describes the composition of a metal
Mill Certification
A report or document from the producing mill that provides all pertinent data relative to the composition, structure, heat, etc. of a given metal
Minimum Headroom
See Headroom
Minimum Sideroom
See Sideroom
Acronym for Maximum Inch-Pounds; (IPPT x Turns = MIP); Used to describe the total torque required on a shaft to raise a given door weight from the floor, and also is the measurement of the torque capacity of a particular wire size at a desired cycle level of operation
Modular Coordination
The dimensioning of building units so that they will fit together, and the use of building dimensions consistent with such coordinated sizes.
Mounting Plate
Flat steel or wood member placed on the wall to accommodate spring supports, spring shaft bearings, chain hoists and mounting for operators
Movable Post
Post designed to allow the use of two or more doors in a single opening with carry-away aluminum center posts that can be removed when doors are in up position.
A bar member supporting and separating panes of glass within a sash or door
See Stile


A synthetic rubber made by polymerizing chloroprene
Nicopress Sleeve
A two-hole aluminum or copper sleeve through which cable is passed. Swaging will upset the sleeve to form a loop at cable end
Normal Headroom
See Headroom
Normal Sideroom
See Sideroom
Numbered Hinge
See Graduated Edge Hinge
Numbered Panel
Area between stiles I.S.L.O. numbered left to right
Numbered Roller Bracket
See Graduated Edge Hinge
Numbered Section
See Door Section
Nylon Center Bearing
See Bushing


See Lubricant
A slight buckling in sheet metal, causing the appearance of waviness or unevenness
See Operator
Opening Height
Distance from floor to the bottom of header
Opening Size
See Daylight Opening
Opening Width
Distance between jambs of the door opening
Electric device used to control the up and down motion of the door
Outside Hook Up
Connection where the counterbalance cable is on the outside of the tracks
Outside Hook-Up Bottom Bracket
Bottom corner bracket where the cable is routed outside the tracks
Outside Pull
See Outside Hook Up
Decorative ornaments of metal, wood or hardboard used for outside decoration of garage door sections


Pan Door
A garage door composed of sheet metal door sections
A raised and decorative design on door sections
Pass Door
A swinging pedestrian door built into a sectional door. Not recognized as an exit door by model codes
Pedestrian Door
Access door adjacent to upward acting doors. Used as a legal means of egress to avoid the use of a sectional door
Perforated Angle
Angled metal with a serried of punched holes used to hang garage doors and operators
Perimeter Seal
Weatherstrip installed at the perimeter of a garage door
Pinch Resistant
Term for a door that has been designed to prevent entrapping, crushing, breaking, severing or dislocating a person’s finger
Plastic Muntin
See Muntin
Pocket Wheel
A wheel or drum machined to receive the individual links of a chain; used to directly transmit power
Pop Rivet
See Blind Rivet
Pounds Pull
Unit of force determined by dividing the torque by the moment arm of the drum
Power Unit
A complete torsion spring assembly consisting of springs, shaft, winding plugs and stationary cones, drums and cables
Finish characterized by galvanized steel painted with a primer, then given an oven-baked top coat
See Pre-Finished
To lay on the first coat of primer paint
Coated with primer paint
Pull Down Rope
A rope connected to the bottom bracket; used to manually pull the door down
Pull Rope
See Pull Down Rope
Pull Type Spring
See Extension Spring
A wheel turning around an axis and having a groove on its rim in which runs a cable, chain, or rope
Pulley Clevis
See Sheave Fork
Punched Angle
See Angle Iron
Punched Angle Brace
See Angle Brace
Punched Angle Iron
See Angle Iron
Punched Angle Track Hanger
See Back Hang
A horizontal roof member spanning between beams and trusses to which roofing is attached; commonly used in a pre-engineered, industrial type building
Push Down Spring
Spring-activated push rods mounted on horizontal tracks to start door down during closing portion of door cycle; generally used with a jackshaft-type operator or a manual chain hoist
Pusher Bumper
A leaf spring in place of a rod
Push Nut
Stamped metal fastener designed to be pushed onto a shaft to secure an assembly


Quarter Grain
See Edge Grain
Quarter Round
Molding showing a quarter circle in its cross section
Quarter Turn
A unit of turn measurement when winding tension into a torsion spring
Quick Turn Bracket
See Low Lift Hardware


Radial Force
A force generated from the center of an object toward the outside
See Horizontal Radius
Radius Track
See Horizontal Radius
Horizontal member of a section
Rain Ledge
See Rain Stop
Rain Stop
Ledge provided at the point where the bottom rail meets the floor to prevent water from running under the door and allowing for runoff of the water onto the drive or approach
Raised Panel
See Panel
Rate of Rise
Measurement of change per revolution of a drum’s moment arm
Rear Mount
When the counterbalance system attached to the rear of the horizontal tracks
Rear-Mounted Torsion
See Rear Mount
Rear Track Hanger
See Back Hang
Indicates color for Left Side, Right Wound
Regular Angle Mount
See Angle Mounted Track
Removable Center Post
Post/track assembly which substitutes for door jamb in wide door openings so that multiple doors may be used instead of a single large door, and which can be released and carried from an opening
Removable Jamb Wall
Wall designed to allow the use of two or more doors in a single opening with carry-away aluminum center posts that can be removed when doors are in up position
Removable Mullion
See Removable Center Post
Removable Post
See Removable Center Post
A sectional overhead type door which is intended for use in a residential garage, and normally operated less than 1,500 cycles per year
Restraining Cable
See Containment Cable
See Sideroom
Reverse Angle
See Reverse Angle Mount
Reverse Angle Mount
An “L” shaped angle with the wall leg toward the door opening used to connect the vertical track to the jamb. Used in low headroom and sideroom restricted garages as well as lap joint.
Rigid Strut
See Strut
Rigid Truss
See Strut
Roll-Away Post
See Removable Center Post
See Track Roller
Roller Assembly
See Track Roller
Roller Bracket
A device that is mounted to a door section and holds a track roller
Roller Stem
See Track Roller
Rounded Off
See Eased Edge
Acronym for “right side looking out”
Thermal resistance value; inverse of U-Value


Safety Bottom Bracket
See Broken Cable Device
Safety Bottom Corner Bracket
See Broken Cable Device
Safety Bottom Fixture
See Broken Cable Device
Safety Cable
See Containment Cable
Safety Spring Containment
See Containment Cable
Safety Spring Containment Kit
See Containment Cable
The framework which holds the glass in a window or door
Sash Muntin
One of the rabbeted bars into which glass is fitted in a sash containing two or more lights
Door opening size designation, denoting “single car”
Scarf Joint
Method of joining pieces of lumber together by gluing and pinning with wood dowels
Cutting a door bottom rail to match the contour of the floor
See Escutcheon
Garage door component that extends the full width of an opening; usually joined together by hinges
Section Joint Meeting Rail Seal
A weather seal between door sections
Section Joint Meeting Rail Type Seal
See Section Joint Meeting Rail Seal
Sectional Door
See Sectional-Type Door
Sectional-Type Door
Door made of two or more horizontal sections hinged together so as to provide a door capable of closing the entire opening and which is by means of tracks and track rollers
See Maintenance
Refers to “single glazed”
Shaft Bearing
A bearing that is used to maintain torsion shaft alignment and reduce friction
A metal or plastic pulley that is designed to guide the cables employed in a counterbalance system
Sheave Fork
A yoke type device used to attach the sheave to extension springs
Shoe Molding
See Quarter Round
Hardware device used to connect an extension spring to a pulley. These are also used with other door related hardware (i.e. chain on locks)
Shop Drawings
Drawings provided by the manufacturer or door supplier to the architect-engineer showing the plans, sections, elevations, and details of the work required, submitted to assure proper interpretation of the intent of the architectural drawings
Side Bearing Plate
See End Bearing Plate
Side Seal
See Stop Mould
A horizontal measurement from each side of the door opening, outward to the nearest obstruction
Single Door
Commonly used to refer to smaller width doors used on one car openings
Single Strength Glass
See Single Thick Glass
Single Thick Glass
A type of sheet glass used in glazing sashes
The pitch of a roof
See Bow
Snap Latch
See Automatic Latch
Solar Glass
A type of tinted glass
Special Door
Non-standard door which must be custom manufactured and/or specified
A detailed statement of the quantity and type of material to be used in the construction of a garage door system
Splice Plate
Plate used for attachment of track at the junction of tracks in clip type angle mounted track
Spring Anchor
See Center Bearing Bracket
Spring Anchor Bracket
See Center Bearing Bracket
Spring Anchor Cone
See Stationary Cone
Spring Anchor Plate
See Center Bearing Bracket
Spring Assembly
See Torsion Spring Assembly
Spring Assembly Closed Wound
A coiled torsion spring with no gaps between the coils
Spring Assembly Open Wound
A coiled torsion spring with equal gaps between each coil
Spring Balance
The amount of turns needed to counterbalance the weight of the garage door
Spring Bumper
Spring mechanism mounted on horizontal track that eases the door to stop in its upward travel to reduce shock and prevent pull down rope breakage. Can be made from leaf springs or tension rods.
Spring Constant
Mathematically developed number from basic spring wire formulas, that applies to any specific wire size and coil diameter combination; used to determine the number of active coils a spring must contain
Spring Containment Device
See Containment Cable
Spring Fitting
A plug or cone used to adapt the torsion springs to the torsion shaft and/or center bearing bracket. One piece is a stationary cone while the other fitting is a winding plug
Spring Hook
See S-Hook
Spring Latch Lock
See Automatic Latch
Spring Pad
Pad installed on header above the door to anchor the center bearing bracket. Can be mounted in various locations, not necessarily in center, depending on size of springs
Spring Plug
See Spring Fitting
Spring Retainer
See Spring Fitting
Spring Winding Cone
See Winding Plug
Square Key
See Key
Standard Headroom
See Headroom
Standard Sideroom
See Sideroom
Stationary Bearing Retainer
See Stationary Cone
Stationary Cone
Part that fits into the end of a torsion spring permitting the spring to be fixed to the center bearing bracket. May also incorporate a retainer for a ball bearing or bushing
Stationary Plug
See Stationary Cone
Stationary Sleeve
See Stationary Cone
Stationary Spring Cone
See Stationary Cone
Steel Jamb
Door framing made from either channel or angle iron
Steel Jamb Mounted
A track system intended for mounting to a steel jamb
Steel Pin
Short, headless pointed nail driven through the dowel and rail in doors for greater security
Step Down Plate
A means of closing a sectional door the last few inches of its travel
Step/Lift Plate
A part that can be used as a step down plate and a lift handle for manually operating a sectional door
See Decal
Vertical reinforcement member of a section
Stock Door
Door made to standard size and generally kept in inventory at either distributor or factory warehouse
See Stop Mould
Stop Mould
Serves to seal the perimeter of the door against weather and light infiltration; usually nailed to the jamb, outside the door
Stop Moulding
See Stop Mould
The amount of work required of a spring at a desired cycle level
Stretch Spring
See Extension Spring
See Striker Plate
See Striker Plate
Striker Plate
A plate used in conjunction with a locking system to secure a lock mechanism
Support stiffener to reduce deflection of the door sections in the horizontal position. Also, to increase windload capability of a door
Sway Brace
See Angle Brace
Sway Strap
See Angle Brace
See Trajectory
Swing-Away Post
A type of removable center post that remains attached at the top and can be pivoted out of the way
Swing-Up Post
See Swing-Away Post


T Handle
A handle in the shape of a “T”
T Lock Handle
See T Handle
Tapered Vertical Track
See Inclined Track
A designation of door opening size indicating an opening for two cars
A pattern used as guide to shape something or show hole drilling locations. Also a short header to support a beam in a wall
Test Load
See Test Wind Load
Test Wind Load
Specified difference in static air pressure (positive or negative), equal to a specified percentage greater than or equal to 100% of the design load
Thermal Barrier
See Thermal Break
Thermal Break
The separation between the outer and inner surfaces of a door section
Thermal Seal
See Bottom Weatherseal
See Oil-Canning
Method of mechanically securing two pieces of steel together without welding, riveting or bolting
Top Carrier
See Top Fixture
Top Fixture
A bracket for positioning the top guide roller on the top section of a door
Top Header Seal
See Top Seal
Top Rail
Horizontal rail forming the top of a door as distinguished from the meeting rails and bottom rail
Top Roller Bracket
See Top Fixture
Top Roller Fixture
See Top Fixture
Top Seal
Weatherstripping which fastens to the top of the door to seal the door along the top of the opening
The twisting force around an axis
Torque Bar
See Torsion Shaft
Act of twisting or turning of a torsion spring by the exertion of forces tending to turn one end about a longitudinal axis while the other end is held stationary
Torsion Bar
A long metal bar that transfers torque from a spring to a winding plug
Torsion Shaft
A shaft that transfers torque from springs to load
Torsion Spring
A spring that works in the manner of twisting one end or part about a longitudinal axis while the other end is held or turned in the opposite direction developing torque
Torsion Spring Assembly
Hardware used to make up door counterbalance assembly
Torsion Spring Counterbalance Assembly
See Torsion Spring Assembly
Torsion Tube
See Torsion Shaft
Torsion Tube Coupler
See Coupler
Channel shaped metal bars or rails in which upward acting doors operate via track rollers
Track Bracket
A fixture, connected to a track, which is designed for the track to be mounted to the jamb
Track Clip
A metal plate used to attach tract to wall angle
Track Graduation
The differential distance from the track to the door jamb, measured at the top and bottom of the vertical track
Track Guard
Added protection for back of vertical track recommended in cases where powered material handling fork trucks and similar equipment may be operating in the area.
Track Hanger Kit
See Back Hang
Track Radius
See Horizontal Radius
Track Roller
Roller assembly for guiding the door sections along track
The arc of travel or sweep of the top section as the door is raised from closed to open position
Translucent Door
Door that allows the passage of light without being transparent
Transom Bar
A horizontal crossbar in a window, over a door, or between a door and a window or fanlight
Transom Section
An extra section above a garage door opening sometimes used to allow extra lift of the horizontal tracks to accommodate a trolley type operator
The finishing materials; such as the lock and handles on the door
Triplex Spring
Three springs of increasing diameter assembled one inside another using special spring fittings
Trolley Opener
See Drawbar Operator
Trolley Type Operator
See Drawbar Operator
See Strut
Truss Bar
See Strut
Tubular Shaft
A hollow shaft
A 360-degree revolution of a component about its axis
Turns On Spring
See Winds On Spring
A form of warp caused by the twisting or winding of the edges of a rail


See Strut
U-Bar Stiffener
See Strut
U-Bar Truss
See Strut
“U” Strut
See Strut
Thermal transmission coefficient which is a measurement of heat, in BTU’s, transmitted through one square foot of material (the door) in one hour at a temperature difference of 1 degree from one side to the other
Upper Trajectory
See Trajectory
Upper Vertical Track
Upper track assembly on a vertical lift door


An opening located in the bottom section of a door for ventilation
Vertical Grain
See Edge Grain
Vertical Lift
Refers to a hardware design that causes doors to open vertically where no horizontal tracks are required
Vertical Lift Drum
A cable drum with changing radius grooves to negate spring tension
Vertical Post
A vertical reinforcement sometimes installed for high wind events
Vertical Splice Angle
See Jamb Angle
Vertical Track
The portion of track that is oriented vertically and is adjacent to the jamb
Vertical Track Assembly
An assembly made up of a piece of vertical track and a piece of continuous angle or jamb brackets used to secure the track to the jamb.
Vision Lite
Glazing that is mounted in a door


Warning Tag
A tag with warnings and/or instructions for safe operation
Water Seal
A coating of some kind used to prevent the absorption of water
Water Stop
See Rain Stop
Weather Joint
See Weatherstrip
See Weatherstrip
Material used at the perimeter of a garage door, or between joints of a garage door, intended to improve a door’s performance against air infiltration and thermal transmission
Wedge Connection
A device composed of a steel wedge and clip for securing the joint between vertical and horizontal track sections
West Coast Lumber
Lumber produced on the West Coast, generally used in manufacturing wood sectional garage doors
Wheel and Axle
See Track Roller
Wicket Door
See Pass Door
Wind Load
See Design Wind Load
Winding Bar
See Winding Rod
Winding Cone
Part that fits into a torsion spring permitting winding and tension adjustment
Winding Cone Set Screw
See Winding Plug Set Screw
Winding Cone Socket Head Set Screw
See Winding Plug Set Screw
Winding Plug
See Winding Cone
Winding Plug Set Screw
Set screw fasteners used to lock the winding plug to the torsion shaft
Winding Rod
A solid rod that fits into the socket of the winding plug to tension torsion springs
Winding Sleeve
See Winding Plug
Window Lite
See Vision Lite
Winds On Spring
The number of winding turns on a torsion spring
Wire Glass
Glass into which wire netting is woven prevent splintering from heat or impact
Wire Rope
See Aircraft-Type Cable
Wire Size
The diameter of the wire in a spring
Wood Anchor Pad
See Spring Pad
Wood Casing
See Wood Jamb
Wood Jamb
Upright wood piece forming the side of an opening
Wood Jamb Mounted
Refers to mounting vertical track to wood jambs
Woodruff Key
Special half-moon shaped steel key