Ives FB31 Automatic Flush Bolt...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$323.20
$156.18
Ives FB31P Automatic Flush Bolt Pair for Metal Doors, 630 Satin Stainless Steel, top and bottom bolts shown extended

Ives FB31 Automatic Flush Bolts for Metal Doors with 3/4" Bolt Throw

(2 reviews) Write a Review

Model: FB31P 12 MD BLK
Selected Finish is
Selected Model is

In Stock (leaves warehouse same day if ordered before 3pm ET)

$323.20
$156.18
Adding to cart… The item has been added
Free Shipping on orders over $199
We price match and offer bulk discounts! Click Add to Quote. It's quick and easy.
✨
Earn points with this purchase! You can redeem points for giftcards, iPads, XBox's and more. View Rewards
Free Keying on all locks
You may also like

Ives FB31 Automatic Flush Bolts for Metal Doors

Automatic Flush Bolt Solution for Double Metal Door Applications

The Ives FB31 automatic flush bolts deliver fully automatic operation for metal door applications. A 3/4" bolt throw with 7/8" vertical adjustment and 3/4" bolt backset provides reliable engagement with installation flexibility. Standard rod length is 12" from the center of the flush bolt body to the bolt tip. Available as a top-and-bottom pair (FB31P), top bolt only (FB31T), or bottom bolt only (FB31B). Non-handed. For use with metal doors only.

Key Features

  • Fully Automatic Operation: Inactive door latches automatically when the active door closes; unlatches when the active door opens - no manual throw required.
  • 3/4" Bolt Throw with 7/8" Vertical Adjustment: Accommodates minor misalignment at jamb and threshold strikes without re-mortising.
  • No Spring Tension on Top Bolt: Low actuation forces reduce wear and make operation smooth over the life of the hardware.
  • 12" Standard Rod Length: Measured from center of flush bolt body to bolt tip; sized for typical metal door applications.
  • Non-Handed: Installs on either leaf without handing - simplifies ordering and field inventory.
  • ANSI A156.3 Type 25 Compliant: Meets the commercial door hardware standard for automatic flush bolts.
  • UL Fire Door Listed: Approved for fire-rated door assemblies - supports code compliance on rated openings.
  • Brass or Stainless Steel Substrate: Choose the substrate that matches corrosion and finish requirements for the application.

Technical Specifications

  • Model: FB31
  • ANSI/BHMA: ANSI A156.3 Type 25
  • Bolt Throw: 3/4"
  • Vertical Adjustment: 7/8"
  • Bolt Backset: 3/4"
  • Standard Rod Length: 12" (center of body to bolt tip)
  • Body Dimensions: W: 1", L: 6-3/4", D: 2"
  • Substrate: Brass or Stainless Steel
  • Door Hand Direction: Non-Handed
  • Application: Metal doors only
  • Commercial/Residential: Commercial

Installation Overview

  1. Verify door thickness and edge preparation requirements for flush bolt mortising against the Ives installation sheet.
  2. Use manufacturer templates to mark mounting hole locations on the door edge, aligned with jamb and threshold strike points.
  3. Rout flush bolt mortise cavities to specified dimensions for both top and bottom bolt assemblies.
  4. Install flush bolt assemblies in prepared mortises and secure per manufacturer torque specifications.
  5. Use the 7/8" vertical adjustment to align bolts with jamb and threshold strikes.
  6. Test automatic operation: close and open the active door to confirm full bolt extension and retraction. Refer to the Ives Full Line Catalog for complete installation details.

Typical Applications

  • Commercial office buildings and retail establishments
  • Educational facilities and healthcare institutions
  • Government and municipal buildings
  • Industrial, warehouse, and multi-tenant residential properties
  • Fire-rated door assemblies requiring UL-listed hardware

Manufacturer Resources

Ives Full Line Catalog

Product Specs

Subcategory:
Flush Bolts and Coordinators
Product Group:
Door Trim and Accessories
Product Subgroup:
Flush Bolts
Product Type:
Flush Bolts
ANSI/BHMA:
ANSI A156.3 Type 25
Commercial/Residential:
Commercial
Product Model:
FB31
Door Hand Direction:
Non-Handed
Product Dimension:
W: 1", L: 6-3/4", D: 2"; Bolt Throw: 3/4"; Rod Length: 12"
Product Category:
Door Trim and Accessories
Product Substrate:
Brass or Stainless Steel
Department:
Door Hardware

Ives FB31P 12 MD BLK – Frequently Asked Questions

1) Are the Ives FB31 flush bolts approved for a fire-rated pair of metal doors?
UL fire door listed, and compliant with ANSI A156.3 Type 25, the commercial standard for automatic flush bolts. That covers the flush bolt hardware on a rated opening. The door, frame, and labels still have to carry their own rating, and the rest of the pair's hardware has to be listed for the assembly.
2) Do the FB31 flush bolts have to be thrown by hand, or do they latch on their own?
They work off the active door. The inactive leaf latches automatically when the active door closes and unlatches when it opens, so nobody has to reach up and throw a lever at the head of the door. The top bolt carries no spring tension, which keeps actuation forces low. If you would rather have bolts that staff set deliberately and leave set, a manual flush bolt such as the ABH 1855S single or the ABH 1854 manual set with fire bolt is the other route.
3) Will the Ives FB31 bolts still engage if my jamb and threshold strikes are slightly out of line?
There is 3/4 inch of bolt throw and 7/8 inch of vertical adjustment to work with, which is enough to bring the bolts onto strikes that sit a little high or low without re-mortising the head or the sill. Rod length is 12 inches standard, measured from the center of the flush bolt body to the bolt tip. Set the height with the adjustment, then cycle the active door and watch that both bolts run out fully and pull clear on the return.
4) How many Ives FB31 do I order for one pair of doors, and what is the difference between FB31P, FB31T and FB31B?
One FB31P covers one inactive leaf: it is the top and bottom bolts supplied together, which is the normal order for a pair of doors. Six pairs of doors in a building means six FB31P. FB31T is the top bolt alone and FB31B is the bottom bolt alone, which is what you order when only one half of an existing set has failed. All three configurations come in the same seven finishes: 605 bright brass, 606 satin brass, 612 satin bronze, 613 satin bronze oil-rubbed, 622 matte black, 629 bright stainless steel, and 630 satin stainless steel.
5) What is the closest cross-brand equivalent to the Ives FB31 automatic flush bolt pair on a fire-rated metal double door?
The ABH 1860P/1862P is the nearest match in operation: it is an automatic flush bolt pair, fire rated 3-hour, with a thermal lock. The Ives FB31P pair is likewise an automatic set - the inactive leaf latches when the active door closes and unlatches when it opens, with no manual throw - and it is UL fire door listed and built to ANSI A156.3 Type 25 for metal doors, with a 3/4 inch bolt throw, 3/4 inch bolt backset, and 7/8 inch vertical adjustment at the strikes. If the specification calls out a 3-hour thermal lock bolt, the ABH pair is written to that language; if it calls out ANSI A156.3 Type 25 automatic flush bolts, the FB31 carries that designation.
6) The opening does not need automatic latching. What manual flush bolt covers the same metal double door as the Ives FB31?
Two ABH options are built for metal doors and thrown by hand. The ABH 1855S is a manual flush bolt single for metal doors with a 3/4 inch throw, which is the same throw the Ives FB31 provides. The ABH 1854 series is a manual flush bolt set with a fire bolt for metal doors, so the bottom position is covered where the opening is rated. The functional difference is who operates the bolt: the FB31 latches the inactive leaf automatically when the active door closes and releases it when the active door opens, while the 1855S and 1854 require someone to reach the leaf and throw the bolt. On an opening where staff regularly need both leaves open, that is the deciding detail.
7) The paired doors are wood, not metal. What flush bolt goes in instead of the Ives FB31?
The Ives FB31 is built for metal doors only, so a wood pair needs a different bolt. The Adams Rite 1877 is a cylinder-operated flushbolt made for paired wood doors. Operation differs as well as the door material: the 1877 is cylinder operated, so the inactive leaf is released with a key, while the FB31 is actuated by the active door itself with no key or tool at the inactive leaf. On a building with both metal and wood pairs, expect two different part numbers rather than one bolt across the whole opening schedule.
8) Do I need to specify a hand when ordering Ives FB31 flush bolts?
Non-handed. The same FB31 installs on either leaf, so there is no left or right to get wrong on the order and no reason to stock two versions on the truck. That is worth knowing when you are standardizing flush bolts across a building of pairs.
9) What size cavity does the Ives FB31 need in the door edge?
The flush bolt body measures W 1 inch, L 6-3/4 inches, D 2 inches, and the bolt sits on a 3/4 inch backset. Those numbers decide whether the mortise clears the internal reinforcement in the leaf, which is the usual snag on a hollow metal door. The rod adds 12 inches from the center of the body to the bolt tip. Cut to the Ives template rather than to a tape measure.
10) Should I use automatic flush bolts or manual ones on the inactive leaf?
Automatic bolts like the Ives FB31 latch and release with the active door, so the inactive leaf secures itself whether or not anyone remembers. That suits a pair that gets cycled all day, or one where the second leaf is opened often for carts and deliveries. Manual bolts stay wherever they were last put, which is fine on a leaf that only opens to move equipment through a few times a year. On the manual side we carry the ABH 1855S single and the ABH 1854 set with fire bolt, both for metal doors.
11) The bottom flush bolt on our inactive door failed but the top one is fine. Can I replace just the bottom?
FB31B is the bottom bolt sold on its own, and it comes in all seven finishes, so the replacement half matches the top bolt still in the door. It is non-handed, so either leaf takes it. One thing to confirm first: the FB31B is automatic and releases with the active door. If the original bottom bolt was a manual bottom fire bolt, the ABH 1858 universal bottom fire bolt is the manual-operation part for that spot instead.
12) Is there a flush bolt for the inactive leaf that can be locked and released with a key instead of by the active door?
Yes. The Adams Rite 1870 series is a cylinder-operated flushbolt with key control, and the 1877 is the cylinder-operated version for paired wood doors. Both put release of the inactive leaf under a cylinder, so only a keyholder opens the second leaf. The Ives FB31 works the other way: it is a fully automatic bolt, latching the inactive leaf when the active door closes and unlatching it when the active door opens, with no cylinder involved. Choose the 1870 or 1877 when the second leaf must stay under key control, and the FB31 when the second leaf should free itself whenever the active door is opened.
13) Only the bottom bolt on the pair is bad. What can be ordered to replace just the bottom position?
Ives sells the bottom position on its own as the FB31B, in finishes including 630 satin stainless steel, 629 bright stainless steel, 605 bright brass, 606 satin brass, 612 satin bronze, 613 satin bronze oil-rubbed, and 622 matte black, so the existing top bolt can stay in the door. Cross-brand, the ABH 1858 is a universal bottom fire bolt with manual operation. Note the operation change before mixing: the ABH 1858 is manually operated, so pairing it under an automatic top bolt means the bottom bolt has to be thrown and retracted by hand while the top continues to follow the active door.
14) Are 6 inch flush bolts such as the Trimco 3999 interchangeable with the Ives FB31?
They are a different style of bolt that happens to share the category name. The Trimco 3999 is a 6 inch corner mount flushbolt with a rounded end and the 3999SE is the square end version of the same 6 inch corner mount bolt; the Orca 86SQ is a 6 inch flush bolt with radius corners; the Delaney 4108 is a 6 inch square end solid brass flush bolt. Each is specified by its faceplate length and end shape. The Ives FB31 is an automatic bolt whose body measures 1 inch by 6-3/4 inches by 2 inches and which carries a 12 inch standard rod from the center of the body to the bolt tip, because the bolt is driven by the active door rather than by a slide on the faceplate. Matching a 6 inch faceplate does not get you FB31 automatic operation, and the FB31 needs a deeper edge preparation for the rod.
15) What should be used if the inactive leaf has to secure top and bottom as one two-point unit?
Adams Rite covers that with two-point hardware. The MS1880/MS1881 are two-point flushbolts with an interlock mechanism, and the MS2180 series is an auto-release two-point flushbolt with a Smartlock mechanism. Both tie the top and bottom positions into a single mechanism on the leaf. The Ives FB31 keeps the two positions as separate assemblies, ordered as FB31T top only, FB31B bottom only, or FB31P as a top-and-bottom pair, each with a 12 inch standard rod, and each following the active door independently. Separate assemblies mean a single failed position can be replaced on its own; a two-point unit means one mechanism controls both.
16) How do you standardize flush bolts across a building that has both metal and wood door pairs?
It usually resolves into two part numbers by door material. Metal pairs take the Ives FB31, which is for metal doors only, non-handed so either leaf takes the same part, UL fire door listed, and built to ANSI A156.3 Type 25; ordering is by model and finish only, FB31P for the pair or FB31T and FB31B for a single position. Wood pairs take the Adams Rite 1877 cylinder-operated flushbolt for paired wood doors. If some metal pairs are to be operated by hand rather than automatically, the ABH 1854 series manual flush bolt set with fire bolt is also built for metal doors. Keeping the metal openings on one non-handed automatic part number is what keeps the stockroom count down.
17) Which Ives FB31 finish should I pick for an exterior or wash-down opening?
Substrate is brass or stainless steel depending on the finish chosen. For exterior-facing entrances, kitchens, or anywhere that gets hosed down, the stainless options are 629 bright stainless steel and 630 satin stainless steel, and both are offered on the FB31P pair as well as the top-only and bottom-only parts. The brass-substrate finishes are the ones to use where you are matching interior trim rather than fighting corrosion.
18) Will Ives FB31 flush bolts hold up on a pair of doors that gets cycled all day?
This is commercial hardware, not residential, built to ANSI A156.3 Type 25. The top bolt runs with no spring tension, so actuation forces stay low every time the active door closes on it, which is what wears an automatic bolt out on a high-traffic pair. Cycling is handled by the active leaf rather than by staff, so there is nothing to be left half-thrown and dragged against a strike.
How fast can I get the Ives FB31P 12 MD BLK delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Ives FB31P 12 MD BLK come with a warranty?
Absolutely. The Ives FB31P 12 MD BLK is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Ives FB31P 12 MD BLK?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Ives FB31P 12 MD BLK from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.

Product Reviews

  • 5
    A Solid Choice for Security and Convenience!

    Posted by George on Sep 4th 2023

    I got myself the IVES FB31 Automatic Flush Bolts for my metal doors. What I dig about these bad boys is their effortless operation; they secure my doors without a fuss. But, here's the hitch – installation ain't a breeze, needs some elbow grease. Overall, they're pretty swell, though!

  • 5
    Easy Bolt Solution!

    Posted by Oscar on Aug 24th 2023

    The Ives FB31 Automatic Flush Bolts are a game-changer. Smooth automatic action keeps my doors secure without the hassle of manual latching. The metal build is sturdy, but installation can be tricky if you're not familiar with hardware. Say goodbye to door drafts with these bolts!

!