Drop-in anchors are primarily used for threaded rod suspended from concrete ceilings.
When a flush mounted concrete anchor is required, the drop-in anchor is an excellent choice. It can be bolted and unbolted to without affecting the holding values.
Each diameter of drop-in anchor comes in only one length. Once the bolt or threaded rod diameter is determined then only one choice of drop-in anchor is available.
5/16 inch, 7/8 inch or 1”
Drop-in anchors are not and never have been available in diameters of 5/16”, 7/8” or 1”. Drop-in anchors are only available in 1/4”, 3/8”, 1/2”, 5/8” and 3/4”.
The design of the drop-in anchors is such that about half the anchor is internal threaded and the other half has the internal expansion plug. When deciding on a bolt length, add half the length of the drop-in anchor being installed to the thickness of the material being fastened.
Drop-in anchors are only manufactured in a zinc plated carbon steel, 304 stainless steel, and 316 stainless steel. They are not manufactured in a galvanized coating for two reasons: the internal threads would be affected, and all the anchor dimensions would need to be changed.
Each diameter of drop-in anchor requires a setting tool. The setting tool corresponds with the designated diameter of the drop-in anchor. If a 3/8” drop-in is being installed, then a 3/8” setting tool is required. Some setting tools are made to ensure full expansion when the lip of the setting tool must meet the lip of the anchor. Many setting tools are not designed like this, and the drop-in anchor is fully set when the expansion plug cannot expand the anchor any further.
The internal plug is set in the drop-in anchor and then affixed in different ways to ensure that it remains installed. If the plug should fall out, it can be reinserted and replaced by simply dropping it into the threaded end of the anchor. It is critically important that the plug is inserted into the anchor with the smallest end first.
The drop-in anchor is manufactured so that if the anchor slipped or was not fully set then the anchor would hold and reset itself.