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Difficulty: HardSpecialty Fasteners and Anchors

A shop technician needs to mount a tool rack onto a hollow drywall partition wall. The mounting hardware must allow the rack to be removed and reattached periodically for routine wall maintenance without the anchor mechanism slipping or falling behind the wall cavity. Which specialty fastener is best suited for this application?

  1. A
    Spring-wing toggle bolt
  2. B
    Plastic conical expansion plug
  3. Expanding sleeve hollow-wall anchor (molly bolt)Answer
  4. D
    Wedge-type expansion anchor

Answer

Expanding sleeve hollow-wall anchor (molly bolt)
An expanding sleeve hollow-wall anchor (commonly known as a molly bolt) consists of an outer metal sleeve with collapsible legs and an internal threaded collar. When initially installed, tightening the screw draws the threaded collar forward, permanently deforming and crimping the sleeve legs against the rear surface of the drywall. Because the outer collar remains locked to the wallboard, the machine screw can be removed and replaced indefinitely to service or remount the tool rack.

Step-by-Step Solution

1
Analyze the substrate and operational constraints specified in the scenario.
The substrate is hollow drywall, and the application requires repeated removal and reinstallation of the fastener without losing the backing anchor.
Different hollow-wall and masonry anchors provide varying degrees of permanent seating and reusability.
2
Evaluate the mechanical behavior of hollow-wall fastening options during disassembly.
Spring-wing toggle bolts lose their spring wing behind the drywall upon screw extraction, whereas molly bolts permanently deform their slotted metal casing to clamp the drywall independently of the screw.
Identifying the anchor that maintains its position when the threaded bolt is withdrawn ensures serviceability.
3
Select the anchor meeting both hollow-wall holding strength and reusable threading requirements.
The expanding sleeve hollow-wall anchor (molly bolt) provides a permanently seated internal threaded sleeve.
This fulfills all requirements of the task without compromising wall integrity or hardware retention.

Key Concept

Hollow-wall specialty anchors and retention mechanics during fixture removal
Estimated Time:1m 15s
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Topics

Specialty Fasteners and Anchors

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