Delaney 7" Slide Type Mortise in Flush Bolt

A flush bolt like the Delaney 7 inch slide type mortises into the edge of the inactive leaf of a door pair and throws a bolt into the head frame or the threshold, holding that leaf fixed so the active leaf has something to latch against. It is operated by hand at the door edge, so it is meant for the leaf that stays shut most of the time, not a door in daily traffic. If you need the inactive leaf to release on its own when the active leaf opens, an automatic flush bolt such as the Ives FB41 set for wood doors is the type to look at instead.

The bolt body is 7 inches long, so the door edge has to take a 7 inch mortise pocket plus the face plate that sits flush with it. On a narrow stile door or a leaf with a lock case or hinge reinforcement already in that stretch of edge, check the pocket before you commit. Shorter bodies exist if 7 inches will not fit, such as the Trimco 3999 at 6 inches or the Orca Hardware 6 inch flush bolt.

Mortise. The body is let into the door edge so only the face plate shows, which is why it needs a routed pocket and cannot simply be screwed onto the face of the leaf. Surface applied corner mount bolts, like the Trimco 3999SE square end, screw to the face and corner of the door and need no routing, so those are the ones to use on a door you do not want to machine.

For a labeled fire door pair, use a bolt that carries the rating on its own listing. The ABH 1860P and 1862P automatic flush bolt pair is fire rated 3 hour with a thermal lock, the Ives FB41 set is rated 90 minutes, and the ABH 1858 universal bottom fire bolt is built for that application. Those are the products to specify when the opening is labeled.

No. The Delaney is a slide type mortise flush bolt, thrown and retracted by hand at the bolt. The Adams Rite 1870 series is a cylinder operated flushbolt with key control, and the Adams Rite 1877 is a cylinder operated flushbolt for paired wood doors. Those are keyed at the bolt so the inactive leaf can only be released by someone with the key, which changes both the door prep and who can operate it. They look similar in the door edge but they are not interchangeable with a hand operated slide bolt.

The Delaney mortise flush bolt is a 7 inch zinc slide type bolt that mortises into the door edge. On the wood door side, the Trimco 3999 flushbolt is a 6 inch corner mount with a rounded end, and the Trimco 3999SE is the same 6 inch corner mount with a square end. Orca Hardware also makes a 6 inch flush bolt with radius corners. The main difference is length and end shape: the Delaney faceplate is 7 inches, while those three are 6 inches, so the mortise pocket and faceplate cutout are not the same and the end profile has to match what the door edge is prepped for.

The Delaney 7 inch slide type mortise flush bolt is operated by hand at the bolt itself. Where the opening needs a fire rated assembly, the ABH 1854 series is a manual flush bolt set supplied with a fire bolt for metal doors, the ABH 1858 is a universal bottom fire bolt of manual operation, and the ABH 1860P/1862P is an automatic flush bolt pair rated 3 hour with a thermal lock. On wood doors, the Ives FB41 automatic flush bolt set carries a 90 minute fire rating and the Ives FB42 is a top automatic flush bolt for wood doors with an auxiliary fire latch. The fire rated inactive leaf hardware is a different family from a plain slide bolt, so confirm the rating required by the opening before substituting either way.

A single Delaney 7 inch mortise flush bolt secures one point, so a top and bottom pair means two bolts and two motions. The Adams Rite MS1880/MS1881 is a two point flushbolt with an interlock mechanism, and the Adams Rite MS2180 series is an auto release two point flushbolt with a Smartlock mechanism. Two point units throw head and sill together, which matters on an inactive leaf that gets operated often or where a release on egress is wanted.

Throw is what determines how far the bolt projects into the head frame or floor strike, so it has to suit the gap at the opening. Among flush bolts of this kind, the ABH 1855S single for metal doors has a 3/4 inch throw, the Ives FB358 manual flush bolt has a 3/4 inch throw with a 1/2 inch bolt diameter, the Ives FB41 automatic set for wood doors has a 3/4 inch throw, and the International Door Closers FB-1202 has a 5/8 inch throw with a 1/8 inch offset and a 7/8 inch backset. When swapping into an existing strike, match the throw and the backset to what the frame is already drilled for rather than to the faceplate alone.

The Orca Hardware 6 inch flush bolt with radius corners and the Trimco 3999 6 inch corner mount rounded end flushbolt are shorter faceplate bolts than the Delaney 7 inch unit, with the Trimco 3999SE offering the same 6 inch corner mount in a square end. Emtek also builds a flush bolt line. A shorter faceplate takes a smaller mortise pocket, so on a closet or utility pair where the 7 inch prep is more cutting than the opening needs, those are the shorter footprint choices.