Rockwood 550 Lever Extension F...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$41.72
Rockwood 550 Lever Extension Flush Bolt

Rockwood 550 Lever Extension Flush Bolt

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Model: 550 US26D
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In Stock (leaves warehouse same day if ordered before 3pm ET)

$41.72
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ROCKWOOD 550 Lever Extension Flush Bolt

Material: Brass;

Finishes: Available in standard architectural finishes;

Fastner: 8 ea. #8 x 3/4" FH combo screws;

Features:

  • For Fire Rated Hollow Metal Swinging Doors measuring up to 4'w x 10'h rated up to and including 3 Hours;
  • 3/4" bolt throw, 3/4" rod backset;
  • 12" rod length (center of face

Options:

  • Other size rods available are 18", 24", 36", 48";
  • Use No. 570 Dust Proof Strike (shown on page E4) to prevent dirt blocking bottom strike
 
ROCKWOOD OVERVIEW
 
Rockwood products are normally used on all types of institutional buildings, offices, retail, educational, detention, sports facilities, hotel and restaurant, and finer residences.
 
ENVIRONMENTAL MANAGEMENT

ASSA ABLOY is commited to protecting the quality of the environment as well as the health and safety of its employees, customers, and the community. Please see our Environmental Health and Safety Policy for details on how we are dedicated to this commitment.

 
 
RESOURCES & DOWNLOADS

Rockwood full line catalog

Manufacturer Resources

Product Specs

Product Group:
Door Trim and Accessories
Fasteners:
8 ea. #8 x 3/4" FH combo screws
Subcategory:
Bolts and Latches
Product Subgroup:
Flush Bolts
Product Type:
Flush Bolts
ANSI/BHMA:
ANSI A156.16, L04251
Commercial/Residential:
Commercial
Handle Type:
Lever
Product Model:
550
Face Plate:
1-1/4" x 6-3/4"
Door Strike:
15/16" x 2-1/4"
Product Category:
Door Trim and Accessories
Department:
Door Hardware

Rockwood 550 US26D – Frequently Asked Questions

1) What is the bolt throw and rod backset on the Rockwood 550 flush bolt?
Three quarters of an inch of throw, with a 3/4 inch rod backset, so the bolt projects 3/4 inch into the head and floor strike. The supplied strike is 15/16 x 2-1/4 inches. If the head channel or threshold on the opening was prepped for a different bolt, check that a 15/16 x 2-1/4 inch strike mortise and 3/4 inch of depth are there before you commit.
2) How much door prep does the Rockwood 550 need, and what size is the face plate?
The face plate is 1-1/4 x 6-3/4 inches, so the mortise in the door edge has to accept that plate flush plus the rod channel above or below it. Standard rod length is 12 inches from the center of the face. Everything mounts with the eight #8 x 3/4 inch flat head combo screws that come with it, no separate fastener pack to order.
3) Is the Rockwood 550 flush bolt manual or automatic, and which should I use?
It's manual. Somebody has to throw and retract the lever by hand at the inactive leaf, which is what most codes require on a normal pair but is not allowed where the inactive leaf has to release automatically. If your opening needs the inactive leaf to free itself when the active leaf opens, look at an automatic set such as the Ives FB41 for wood doors or the ABH 1860P/1862P automatic pair. For a fire opening needing a self-latching bottom bolt, the ABH 1858 universal bottom fire bolt is the manual-operation alternative.
4) What is the closest substitute for a Rockwood 550 flush bolt on a metal door?
The Ives FB457 with a 12 inch rod is the nearest like for like, a manual flush bolt for metal doors at the same 12 inch standard rod length. The Ives FB358 manual bolt also carries the same 3/4 inch throw with a 1/2 inch bolt diameter, and the ABH 1855S is a manual single bolt for metal doors with 3/4 inch throw. Any of the three will seat 3/4 inch into an existing strike prep the way the 550 does; the face plate and strike cutouts are what you have to check against the door already in the frame.
5) What is a straight equivalent to the Rockwood 550 flush bolt for a metal door with a 12 inch rod?
The Ives FB457 manual flush bolt is specified with a 12 inch rod length for metal doors, matching the Rockwood 550's 12 inch rod length and manual operation on hollow metal doors. The Rockwood 550 uses a lever extension actuator with a 3/4 inch bolt throw and 3/4 inch rod backset, and takes a 1-1/4 inch by 6-3/4 inch face plate. Confirm the face plate cutout in the door edge before swapping, since the two are prepped to their own face plate dimensions.
6) Do I need a dust proof strike with a flush bolt in the floor?
On the bottom bolt, yes, in any location that collects grit. Rockwood calls out the No. 570 dust proof strike for use with the 550 to keep dirt out of the floor strike, which is the usual reason a bottom bolt stops seating. The top strike doesn't have that problem. Order the 570 separately, it is not packed with the bolt.
7) What standard does the Rockwood 550 flush bolt meet?
ANSI A156.16, type L04251. That's the auxiliary hardware standard, and the L04251 type number is the one a spec writer or institutional buyer will want to see matched on the submittal for a manual extension flush bolt. It is a commercial grade product, not residential trim.
8) I need to lock the inactive leaf with a key instead of by hand. What are my options?
The 550 is lever operated at the door edge, so it takes no cylinder and anybody standing at the inactive leaf can throw it. Where you need key control over that leaf, the Adams Rite 1870 Series is a cylinder operated flushbolt, and the MS1880/MS1881 and MS2180 are two point flushbolts, the MS2180 with an auto release Smartlock mechanism. Those are the ones to look at when a tenant or the public can reach the inactive leaf.
9) How many Rockwood 550 flush bolts do I need per pair of doors?
Two per inactive leaf on a normal pair, one at the head and one at the sill, since the 550 is a single extension bolt rather than a top-and-bottom set. Each one arrives with its own strike and its eight #8 x 3/4 inch combo screws. If you want the set supplied as a pair in one box instead, the ABH 1854 Series is a manual flush bolt set with fire bolt for metal doors.
10) What is the closest ABH match to the Rockwood 550 for a fire rated metal door pair?
The ABH 1854 series is a manual flush bolt set with fire bolt for metal doors, and it is the nearest manual set to the Rockwood 550, which is a manual lever extension bolt for fire rated hollow metal swinging doors rated up to and including 3 hours. The Rockwood 550 is brass with a 3/4 inch throw and ships with 8 each #8 x 3/4 inch flat head combo screws, in 619 satin nickel and 626 satin chrome.
11) What is the difference between the Rockwood 550 and a 6 inch corner mount flushbolt like the Trimco 3999?
They mount differently. The Rockwood 550 is a lever extension flush bolt with a 12 inch rod and a 1-1/4 inch by 6-3/4 inch face plate mortised into the door edge, with other rod lengths of 18, 24, 36 and 48 inches. The Trimco 3999 is a 6 inch corner mount flushbolt with a rounded end, and the Trimco 3999SE is the same 6 inch corner mount with a square end. Corner mount bolts sit at the door corner rather than running a rod up the edge, so they are not a drop-in for a 550 prep.
12) Can I use the International Door Closers FB-1202 in place of a Rockwood 550?
Check the throw and backset first. The Rockwood 550 has a 3/4 inch bolt throw and a 3/4 inch rod backset. The International Door Closers FB-1202 is a flush bolt with a positive U joint actuator, a 5/8 inch throw and a 1/8 inch offset with a 7/8 inch backset, square end, with guide. The shorter throw and different backset mean the strike engagement and the door edge prep are not the same, so it substitutes only where the frame and threshold strikes are being prepped fresh.
13) Which flush bolt do I use if only the bottom of the inactive leaf needs a bolt?
The Rockwood 550 is ordered as a lever extension flush bolt with a 12 inch rod and additional rod lengths of 18, 24, 36 and 48 inches, so top and bottom are specified individually. If you only need one, the ABH 1855S is a manual flush bolt single for metal doors with a 3/4 inch throw, the same throw as the 550, and the ABH 1858 is a universal bottom fire bolt with manual operation. For the Rockwood 550 at the bottom, the No. 570 dust proof strike keeps dirt out of the floor strike.
14) What flush bolt gives key control of the inactive leaf instead of a lever the way the Rockwood 550 does?
The Rockwood 550 is operated by a lever extension at the door edge, so anyone with access to the edge of the open leaf can throw it. If the inactive leaf has to be controlled by key, 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. Cylinder operated bolts need a cylinder specified and keyed into your system, which the lever operated 550 does not.
15) Is a two-point flushbolt the same thing as the Rockwood 550?
No. The Rockwood 550 is a single lever extension flush bolt with a 3/4 inch bolt throw, ordered per bolt with rod lengths of 12, 18, 24, 36 and 48 inches. The Adams Rite MS1880/MS1881 are two-point flushbolts with an interlock mechanism, and the Adams Rite MS2180 series is an auto-release two-point flushbolt with a Smartlock mechanism. A two-point unit drives top and bottom from one mechanism, so the door prep and the hardware count on the inactive leaf are different from a pair of 550s.
16) Will a solid brass residential flush bolt work where a Rockwood 550 is specified?
The Rockwood 550 is a commercial flush bolt built to ANSI A156.16, L04251, for fire rated hollow metal swinging doors rated up to and including 3 hours. The Delaney 6 inch square end solid brass flush bolt and the Delaney 7 inch slide type mortise in flush bolt are shorter mortise bolts, and the Emtek flush bolts are a separate flush bolt line. Where a fire rated hollow metal pair is the opening, specify to the fire rated hollow metal application the 550 covers.
17) What finishes does the Rockwood 550 flush bolt come in?
Two: 619 satin nickel and 626 satin chrome. Both are brass base metal. If the rest of the openings in the building are 626 satin chrome, which is the common commercial finish on levers and exit hardware, the 550 matches without a special order.
18) How does a 6 inch flush bolt with radius corners compare to the Rockwood 550?
The Orca Hardware 6 inch flush bolt with radius corners is a short bolt with rounded plate corners, while the Rockwood 550 carries a 1-1/4 inch by 6-3/4 inch face plate and a 15/16 inch by 2-1/4 inch door strike, with a 12 inch rod as standard. The face plate footprint and strike size decide whether an existing door and frame prep accepts the bolt, so measure the existing mortise and strike cutout before treating one as a swap for the other.
19) Is the Delaney 7 inch mortise extension flush bolt the same style as the Rockwood 550 lever extension?
Both are extension style bolts, but they are prepped differently. The Delaney 4363 is a 7 inch mortise extension in flush bolt. The Rockwood 550 is a lever extension flush bolt with a 1-1/4 inch by 6-3/4 inch face plate, a 3/4 inch rod backset and a 12 inch rod, with 18, 24, 36 and 48 inch rods also available. Match the face plate length and the rod length to the existing mortise rather than assuming the extension styles interchange.
How fast can I get the Rockwood 550 US26D 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 Rockwood 550 US26D come with a warranty?
Absolutely. The Rockwood 550 US26D 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 Rockwood 550 US26D?
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
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