Mechanical Anchor Fasteners
Mechanical anchors physically leverage friction anchor themselves in place. Often, the base of an anchor is designed to expand in diameter when it is inserted into the hole, such that, the expansion strongly grips the base material and wedges the anchor firmly in place. The force used in pushing the anchors the screw in place and prevents it from falling out.
In the world of mechanical anchors, the diameter of the hole drilled plays a critical role. It is important that the hole diameter is just right, because, if it is too large then it fails to sufficiently grip the sides of the hole and thus collapse when it is put to loading.
Mechanical vs. Chemical Anchor Fasteners – Which one should you choose?
The fundamental differences between chemical and mechanical fasteners are listed below:
Speed: Load can only be applied to chemical fasteners once the chemical has set completely, whereas, a load can be applied on mechanical fasteners immediately upon installation. So, in case of speed-critical projects, it would be ideal to choose mechanical fasteners. However, there are quick-setting anchor epoxies (chemicals) on the market that take about 45 min to 1 hour to set, while regular epoxies take around 12-24 hours.
Waterproofing: Most mechanical anchors leave a slight gap between the fastener and the base material. In case of fastener installations outside the building like fixing an external AC unit, signage, or TV antenna, a mechanical fastener version may cause leakage into the building. In such a scenario, a chemical fastener is superior as the epoxy chemical fills up the recess between the bolt and base material, rendering a water-tight connection. Chemical fasteners are therefore suitable for external fastenings where leakage may be a pertinent factor.
Load Capacity: Regarding load capacity, it is not that one version of the fastener can bear more load than the other. Both the versions i.e. chemical and mechanical fasteners are available in a wide range of load ratings and capacities.