Trimco 3810 Automatic Flush Bolt, Metal Door, OA (Overall Size) 1 x 6-3/4"

The 3810 is the metal door version of Trimco's 3800 Series automatic flush bolt, so it's prepped for hollow metal and steel doors, not wood. The body is 6-3/4 x 1 x 1-5/8 inches, so the inactive leaf needs a mortise pocket that depth in the edge. If your inactive leaf is wood, you need the wood door version of the series instead, not this one.

A manual flush bolt has to be thrown and retracted by hand at the top and bottom of the inactive leaf, which means someone has to open the pair and reach up to release it. The 3810 is automatic: closing the active leaf projects the bolts, and opening the active leaf releases them, so the inactive leaf frees itself without anyone touching it. That's what makes automatic bolts the choice on egress pairs and on openings where staff shouldn't have to prop the inactive leaf. The 3800 Series is built to need very low closing force to secure, so the pair doesn't have to be slammed to latch.

Automatic flush bolts go in pairs on the inactive leaf, one at the top edge and one at the bottom, so plan on two 3810 bodies per opening. Each one comes with a 2 x 1 x 1/16 inch guide. Beyond the bolts you still need a strike at the head and a floor strike or dust proof strike at the threshold, plus whatever lock or latch secures the active leaf. The 3800 Series uses interchangeable trim kits, so the faceplate finish can be changed without swapping the bolt body.

The bolt body measures 6-3/4 x 1 x 1-5/8 inches and the guide is 2 x 1 x 1/16 inches. Prep the inactive leaf edge to take that body, and note that the door itself has to be thick enough to accept a 1-5/8 inch dimension inside the edge. On a factory prepped hollow metal leaf ordered for automatic flush bolts, confirm the manufacturer's cutout matches those numbers before the doors ship, because a metal leaf is not something you enlarge in the field the way you would a wood one.

Yes, that's its intended use. Trimco lists the 3800 Series for commercial and industrial buildings, hospitality, multifamily and mixed-use, and office buildings. The parts that take the wear are stainless steel, and the reduced part count means fewer things to bind on a door that cycles all day. It's a commercial grade part, not a residential one.

Square bolt. That matters when you're reusing an existing strike: a square bolt wants a square cutout in the head strike and floor strike, so a round-bolt strike left over from another manufacturer's flush bolt won't be a clean match. Order strikes intended for a square bolt with it.

Satin chrome / satin stainless steel is the finish offered, which reads as the standard brushed silver that matches most commercial lever trim and hollow metal hardware in an office or multifamily corridor. If you are standardizing an inactive leaf across a building, that's the one finish to plan around on the 3810.

Noise is the reason this design exists. Trimco built the 3800 Series to run quiet and to need very low closing force, which matters on hotel corridors, apartment cross-corridor pairs, and offices where a clacking bolt on every door cycle becomes a complaint. The patented design uses about a third fewer parts than a conventional automatic bolt, with the key components in stainless steel.