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OBThe Overhead Bench

Field notes on sectional doors, their operators and the hardware that carries them

Springs and balance

Torsion and extension springs, cables, drums and the weight balance that decides how long an operator lasts and when a door becomes dangerous to lift.

Every work order on this bench

2
  1. A garage interior at midday, sunlight through an open side window, showing the vertical track, a lag-screwed bracket into a wood header, and a torsion shaft above the door.

    SB-002Springs and balance

    The Load Path of a Sectional Door

    How a sectional door's weight moves from panel to track, bracket and header, and why the parts that carry it are sized as one chain.

  2. A galvanized steel torsion spring and cable drum mounted above a garage door header, lit by a bare shop light, with rust bloom visible on the cable and a concrete floor below.

    SB-001Springs and balance

    Corrosion on Garage Door Hardware

    Road salt and coastal air attack the hinges, rollers, cables and springs that carry a sectional door. Here is where corrosion starts and when a part is