Metallics M6306SD Anchors 3/8 Smart-Di Drop-In Ancr C-St (Jar 50), 100 Pack

You need the matching 3/8 setting tool. A drop-in anchor like the M6306SD works by driving an internal plug down with the setting tool to expand the shell against the hole wall. Threading a bolt in without setting it first leaves the anchor unexpanded and it will pull out under load. The setting tool is a separate item and is not part of the anchor pack.

A 3/8 inch drop-in anchor is drilled with a 1/2 inch carbide bit, since the anchor shell outside diameter is larger than the 3/8 thread it carries. Drill to full anchor depth, blow the hole clean, then drop the anchor in flush with the surface and set it. Anchor size and bolt size are the same number here (3/8); the drill bit is not.

It is a carbon steel anchor, so keep it to dry interior concrete. Carbon steel drop-ins will corrode in exterior, wet, or washdown areas. For those conditions specify a stainless drop-in instead.

A drop-in sets flush in the concrete and gives you a female 3/8 thread, so the rod or bolt can be backed out and the fixture removed without leaving a stud sticking out of the slab. A wedge anchor is a male stud that stays proud of the surface permanently. For overhead rod-hung conduit, strut, and trapeze work, electricians usually run drop-ins for that reason. Use a wedge anchor where you are through-bolting a base plate to a floor and a protruding stud is not in the way.

They ship in jar packaging rather than a loose bag or box, which is what you want on a cart or in a gang box where loose anchors get lost. The jar keeps a full run of 3/8 drop-ins together for repetitive overhead rod work.