Design Hardware UL Auto Flush Bolt (Wood Doors)

No. This auto flush bolt is built for wood doors. For a hollow metal pair, look at a metal-door flush bolt instead, such as the ABH 1855S manual flush bolt for metal doors or the ABH 1860P/1862P automatic flush bolt pair. Mortise prep in wood and in hollow metal are not interchangeable, so ordering the wood version for a steel door leaves you with a pocket that will not take the case.

The bolt runs on a 3/4 inch rod backset, so the rod channel is bored 3/4 inch in from the door edge face. The face plate is 1 inch by 6 3/4 inches, which is the routed cutout you need in the edge of the inactive leaf.

The bolt throws 5/8 inch and the head is adjustable up to 1 1/2 inches, so you have room to take up gap variation at the head and sill. The supplied strike is 15/16 inch by 2 1/4 inches. If your existing strikes are a different cutout size, plan on swapping them rather than trying to make the new bolt reach an odd opening.

Plan on a dust proof strike at the floor. Design Hardware calls for the DPS-1 dust proof strike so dirt does not pack the bottom strike and block the bolt from seating. You will also want to confirm the active leaf lock or exit device is ordered separately; a flush bolt only secures the inactive leaf.

The Design Hardware UL auto flush bolt releases automatically with door operation, so it does not restrict who can free the inactive leaf. Where key control over the inactive leaf is the requirement, the Adams Rite 1877 is a cylinder-operated flushbolt for paired wood doors, and the Adams Rite 1870 series is a cylinder-operated flushbolt with key control. Those require a cylinder and keying to be specified as part of the order.

The Design Hardware UL auto flush bolt is prepped for wood doors, so for a hollow metal inactive leaf look at the metal door bolts instead: the ABH 1854 series manual flush bolt set with fire bolt for metal doors, the ABH 1855S manual single with 3/4 inch throw, or the Ives FB457 manual flush bolt with a 12 inch rod. Note that all three are manual operation, so the inactive leaf is thrown by hand rather than automatically on closing.

The Design Hardware UL auto flush bolt is prepped for wood doors. For narrow stile aluminum pairs, the Adams Rite MS1880/MS1881 two-point flushbolts with interlock mechanism and the Adams Rite MS2180 series auto-release two-point flushbolt with Smartlock mechanism are the two-point devices built for that application. The MS2180 auto-release behavior is the closer match if you want the inactive leaf to release without a separate manual action.

The Design Hardware UL auto flush bolt throws and releases with door operation, using a 5/8 inch bolt throw and a 3/4 inch rod backset. A manual bolt such as the Delaney 7 inch slide type mortise flush bolt, the Delaney 6 inch square end solid brass flush bolt, or the Trimco 3999 6 inch corner mount rounded end flushbolt is operated by hand at the bolt lever each time the inactive leaf is opened or secured. Automatic units are usually chosen where the inactive leaf must self-secure on closing; manual units are chosen where the leaf stays fixed for long periods.

The ABH 1860P/1862P is an automatic flush bolt pair that is fire rated 3-hour with a thermal lock, so it shares the automatic operation, but it is a different product line from the Design Hardware wood door auto flush bolt and should be confirmed against your door material and prep. The Design Hardware unit is built for wood doors with a 3/4 inch rod backset and a 15/16 inch by 2 1/4 inch strike. If the opening is spec'd for a specific fire rating, verify the bolt against the door manufacturer's listing before substituting either way.

The Design Hardware UL auto flush bolt is the wood door automatic bolt with a 5/8 inch throw and a 15/16 inch by 2 1/4 inch strike. On the Ives side, the FB41 automatic flush bolt set for wood doors carries a 90 minute fire rating, and the FB42 top automatic flush bolt for wood doors is supplied with an auxiliary fire latch. If the opening carries a specific rated label, match the bolt to the rating the door manufacturer's listing calls for.

They are not interchangeable. The Design Hardware UL auto flush bolt is a wood door automatic bolt with a 1 1/2 inch adjustable bolt head and a 5/8 inch throw. The ABH 1858 is a universal bottom fire bolt with manual operation, which serves as an auxiliary bottom device rather than the primary automatic bolt for the inactive leaf. On a fire-rated pair, check the hardware schedule for whether both a bolt and a separate fire bolt are called for.

The Design Hardware UL auto flush bolt throws 5/8 inch with a 3/4 inch rod backset. Among the manual options, the International Door Closers FB-1202 also uses a 5/8 inch throw, with a 1/8 inch offset, a 7/8 inch backset, a square end and a guide, and a positive U joint actuator. The throw matches, but the backset differs, so verify the rod pocket location in the door edge before substituting.

The Design Hardware UL auto flush bolt is a 3/4 inch rod backset unit with a 1 inch by 6 3/4 inch face plate. Where a longer reach is required, the Ives FB457 is supplied with a 12 inch rod length for metal doors, and the Delaney 7 inch mortise extension flush bolt is the extension style for a taller face. Rod length is normally driven by how far above the face plate the top strike sits, so measure that dimension first.

Steel base material, which is the standard construction for a commercial flush bolt and holds up better than the cast solid brass decorative types like the Delaney 6 inch square end solid brass flush bolt, which are aimed at residential and light interior pairs.

The Design Hardware UL auto flush bolt comes in 613 dark bronze and 626 satin chrome over a steel base material, which are the standard commercial architectural finishes. If a residential or decorative appearance is the driver, the Delaney 6 inch square end solid brass flush bolt and the Emtek flush bolts are the decorative-leaning options, and the Orca Hardware 6 inch flush bolt with radius corners offers a rounded face plate profile. Those are manual bolts, so you would be trading automatic operation for the appearance.

It matters only for how the face plate seats in the existing mortise. The Design Hardware UL auto flush bolt uses a 1 inch by 6 3/4 inch face plate. Among manual corner mount alternatives, the Trimco 3999SE has a 6 inch square end face and the Trimco 3999 a 6 inch rounded end, so the routed pocket has to match the end profile you order or the plate will not sit flush.