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Flush Bolts and Surface Bolts

When you have a pair of doors, the inactive door will have to be held secure in some way so that the active door can lock into it. When you are using exit devices on the doors, a vertical rod panic device on the inactive door takes care of this. When you have a standard lock on the active door, you will have to use either flush bolts or surface bolts.

The standard lever extension flush bolts are shown below. One is installed in the top edge of the door and the other in the bottom edge. You simply operate the levers up or down to set or open the flush bolts while the active door is open. These are the standard flush bolts supplied with doors and what we supply unless something else is specified.

lever extension flush bolts commercial doors

Automatic flush bolts serve the same purpose as the standard flush bolts except that they are automatic and do not require manually working the lever up or down. When the active door closes, it makes contact with the latches on the surface plate which causes the flush bolts to move up at the top and down at the bottom locking the inactive door. When the active door is opened, the flush bolts automatically retract leaving the inactive door unlocked as well.

automatic flush bolts hollow metal doors

Combination flush bolts have an automatic flush bolt at the bottom. The top bolt is actually a latch (just like the latch on a standard lockset) versus a bolt. The inactive door can be closed without any manual operation as this latch will retract (the same as a lock latch does) when the door is closed and it will extend back out once completely closed. When the active door is opened, the top flush bolt can be released by pressing a plunger button on the bolt face.

combination flush bolts for pairs of doors

Flush bolts mount in the edge of the door and they are concealed when the doors are closed. Surface bolts mount on the inside surface of the door making them exposed. As a hardware item, they are roughly the same price as the standard flush bolts but there is no prep work involved on the door or frame for surface bolts which makes the overall cost a little cheaper. These are good to use for storage room doors and other ares where appearance is not a concern.

heavy duty surface bolts for pairs of doors

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