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Glossary of Garage Door Terms - O to Si

Opening Size:
Frequently called daylight opening or finished opening. Dimensions are taken between masonry or wood walls or between steel jambs.

Opening Width:
Distance between jambs of the door opening.

Outside Hook-up:
Bottom fixture with an arm that bends around vertical track to receive lifting cables. Generally used with low headroom hardware.

Wood framing at jambs and header to which door track is mounted. Usually furnished by general contractor. Refer to Jambs.

The area between vertical stiles in a door section.

Perimeter Seal:
Complete weather-stripping package for sectional doors, consisting of astragal, jamb seal and header seal.

Perimeter Wear-strip:
Vinyl or felt attached to corrugated sheet door curtain to prevent rubbing. Located at the ends or drum locations.

Rabbet Joint:
Joint formed by fitting together rails with grooves cut out of the opposing edges to permit overlapping weather tight meeting of sections. Refer to Shiplap Joint and Tongue and Groove.

The curved portion of the track, which allows the door to move from vertical to horizontal (and vice versa). The curve is measured in inches, thus determining headroom requirements. Refer to Headroom.

Rain or Water Stop:
A step at the edge of the garage floor, approximately 1 (25.4 mm) higher than the outside finish. The door sits between the two.

Rear Track Hangers:
Often constructed of punched angle iron, laterally braced, these hangers attach the end of the horizontal track to the garage ceiling. Refer to Back Hangs.

Roller Assembly:
The combination of a wheel and axle that is used to guide a door through the track system, either 2″ (50.8 mm) or 32″ (76.2 mm) diameter, depending on track size. Available as short or long stem.

Steel, ball-bearing wheels that allow sections to roll freely along door tracks.

Safety Spring Containment:
An extra cable used with extension springs to prevent pieces of the spring from causing damage or injury in the event the spring breaks. The cable is threaded through the center of the spring and is secured on both ends of the horizontal track.

Sectional Joint Meeting Rail Seal:
A weather-strip integral with the section at the joints between door sections.

Sectional Type Doors:
Doors made of two or more horizontal sections hinged together to provide a door large enough to close the entire opening. Sectional doors are guided into the horizontal or open position by a system of vertical or horizontal tracks. May be fabricated of continuous roll-formed steel with reinforcing ribs, flush sections of steel or aluminum.

Shaft Bearings:
Type of bearing that adequately supports the radial forces dictated by the weight of the counterbalance assembly and door weight, and the lateral forces exerted. Refer to Center Support Bearing.

Shafts, Tubular and Solid:
A tubular or solid steel counterbalance shaft transmits lifting force of the torsion springs to the cable drums and lifting cables.

A pulley with integral ball bearings designed to handle a cable and used to control the movements of the cables employed in the door counterbalance system. Various types are stud or clevis.

Shiplap Joint:
The configuration of the meeting rails. When closed, the shiplap prevents rain, wind, and light from infiltrating the door between the door sections. Refer to Tongue and Groove.

A horizontal measurement from each side of the door opening outward along the wall to the nearest obstruction within the building.

A to C

D to He

Hi to M

Sp to Z