The Types of Double Fasteners

Double-End Studs

• Normal thread studs have only one type of threading that moves in only one direction. These threads are used mostly for piping and plumbing attachments. However, some types of threaded studs have two ends, with separate thread on both sides. This allows them to be screwed in on each side for a greater balance of support. Some are equally double ended, while others have more threading on one side than the other.

Double Expansion Anchors

• Expansion anchors are designed for cement and concrete. They are inserted into the concrete, usually as a screw-in or tap-in addition. Then a bolt is inserted inside the anchor. The anchor automatically expands, locking itself and the bolt in place in the concrete. A double expansion anchor has two different sizes designed for two different types of bolts, making them more versatile.

Sizing

• Double anchors have several different size ranges depending on their use. Some are only 1/4 and 5/6 of an inch, which are used for lighter loads. Others are 5/8 and 3/4 of an inch in diameter, and are used for heavier loads that require larger bolts and a greater amount of traction within the concrete.

Double Placement Anchors

• Some anchors are not holding slots for bolts, but actual screws and nails that hold together different components, such as window frames and window molding. In this case, a double anchor is a more literal term. It uses two different fasteners, a set of double nails to creates a stronger attachment. Sometimes these nails are bridged like a staple, and sometimes they have separate heads.