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Difficulty: MediumSpecialty Fasteners and Anchors

A builder is mounting a utility rack onto a drywall partition and requires an anchor that permanently collapses behind the wallboard, allowing the mounting screw to be repeatedly removed and replaced without losing the anchor inside the wall cavity. Which of the following specialty fasteners is specifically designed for this application?

  1. A
    Spring-wing toggle bolt
  2. Hollow-wall sleeve anchor (molly bolt)Answer
  3. C
    Solid masonry wedge anchor
  4. D
    Finish wire brad

Answer

Hollow-wall sleeve anchor (molly bolt)
A hollow-wall sleeve anchor (commonly known as a molly bolt) consists of a machine screw inside an expandable, slotted metal sleeve. As the screw is tightened during initial installation, the sleeve collapses outward to form rigid metal legs that clamp tightly against the rear surface of the drywall. The threaded inner collar remains permanently fixed in place, allowing the center screw to be removed and reinstalled as often as necessary without losing the anchor inside the wall.

Step-by-Step Solution

1
Identify the base material and operational requirement
The substrate is hollow drywall, and the screw must be removable and replaceable without losing the back anchor.
Different hollow-wall anchors have different retention behaviors when their fasteners are backed out.
2
Evaluate the mechanical action of sleeve-type anchors versus spring toggles
A hollow-wall sleeve anchor (molly bolt) draws its slotted metal casing into expanded legs firmly clamped against the backside of the drywall, permanently seating the threaded barrel.
This allows the center machine screw to be unthreaded and re-fastened repeatedly without the anchor falling into the stud bay.

Key Concept

Hollow-wall expansion sleeve anchor retention mechanics
Estimated Time:1m 0s
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Topics

Specialty Fasteners and Anchors

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