Dorma C550 Grade 2Entry/Office Keyed Lever Lockset

No. The C550 tops out at 1-3/4 inches. For a thicker door, the Cal-Royal CAL20 and CAL30 Grade 1 locksets cover up to 2 inches, and the Kwikset 912TNL SmartCode lever handles 1-3/8 to 2 inches. Forcing a lock past its stated thickness range leaves the spindle and mounting posts short and the lever will not seat.

The C550 ships with a 2-3/4 inch backset latch, part 15250, with a 1 inch square corner faceplate. If your door is already bored on the 2-3/4 inch backset (the deeper of the two standard commercial backsets), it drops in. If your existing prep is 2-3/8 inch, this will not line up.

A 5001 strike is included: the ANSI 1-1/4 x 4-7/8 inch square corner strike. That is the full-size ANSI frame prep, so a hollow metal frame already prepped for ANSI strikes takes it directly. A residential frame with a small T-strike cutout will need to be enlarged or reinforced.

It is the F82A entrance/office function. The outside lever is locked or unlocked by a pushbutton or turn on the inside, and the key retracts the latch from outside; the inside lever always retracts the latch for free egress. That is the function you want on a tenant suite door, a manager's office, or an apartment entry where staff need key access but the occupant controls locking.

The C550 is ANSI/BHMA A156.2 Series 4000 Grade 2 certified and built for commercial use. Grade 2 is the middle commercial tier, suited to moderate traffic: apartment and hotel unit doors, offices, churches, municipal buildings, retail and warehouse doors. For a high-traffic school or hospital corridor door, step up to a Grade 1 lockset such as the Marks USA 195RAB Survivor Series entry lever, which carries the same entrance/office function at Grade 1.

Yes. The C550 is offered in a J cylinder configuration, SFIC less core, so you can install your own small format interchangeable core and keep the whole building on one keying system. If you are not running SFIC, order the D conventional cylinder version instead, which comes as a standard single-cylinder keyed lock. Both cylinder types are available across all six finishes and all three lever designs.

Sometimes, but check the door thickness before you commit. The C550 adjusts for doors 1-3/8 inch to 1-3/4 inch thick, which covers most of the hollow metal and wood doors it goes on. The Alarm Lock Trilogy T2 DL2700 is a Grade 1 standalone electronic cylindrical lock with a digital keypad, 100 user codes and IC/SFIC compatibility, but it fits doors 1-5/8 inch to 1-7/8 inch - so a 1-3/8 inch door carrying a C550 today is outside its range. The Lockey E985 electronic keypad lever lock with key override covers 1-3/8 inch to 1-3/4 inch, matching the C550's range exactly.

The Stanley Security QCL150 is the nearest match. Both are Grade 2 cylindrical locksets in an entrance function with a lever trim, and both use a 2-3/4 inch backset latch with a 4-7/8 inch by 1-1/4 inch ANSI strike, so the door prep carries over without redrilling. The QCL150 ships in the Sierra bent lever style and comes less cylinder; the C550 offers LC, LG and LR lever styles and can be ordered with a conventional cylinder or as SFIC less core.

Two routes. The Dorma C550 itself is orderable with a J - SFIC Less Core cylinder in all three lever styles, which keeps the entrance/office function. If the opening needs a storeroom function instead - locked at all times, key retracts the latch - the Marks USA 175RF SFIC is a Grade 2 storeroom clutched lever lockset, small format IC less core, on a 2-3/4 inch backset with an ANSI strike, so it shares the same door prep as the C550.

The Marks USA 195RAB is a Grade 1 entry clutched lever lockset in the Survivor Series, supplied less core with an American lever. It carries the same entrance/office function as the Grade 2 C550, so the door behaves the same way for the occupant while the chassis is built to the higher ANSI/BHMA grade. The C550 remains the Grade 2 choice where A156.2 Series 4000 Grade 2 is what the spec calls for.

The C550 is a keyed single cylinder entrance/office lock, so it is the wrong function for an unkeyed door. For a corridor or closet door that only needs latching, the Orca Hardware OCL210 is a Grade 2 passage cylindrical lockset; for a restroom or bedroom, the Orca OCL240 is a Grade 2 privacy cylindrical lockset. Both are medium duty. If the door needs a key but not the entrance/office function, the Orca OCL250 is the Grade 2 keyed entrance version.

Six finishes: 605 bright brass, 606 satin brass, 613 oil rubbed bronze, 619 satin nickel, 625 bright chrome and 626 satin chrome. 626 satin chrome is the usual commercial default and the one most existing office and apartment hardware will match. Every finish is available with either cylinder type and any of the three lever designs.

Handing on the C550 depends on which lever you select, so you need to know whether the door is left or right hand before ordering. Three lever designs are offered: LC, LG and LR. Stand outside the door, and the side the hinges are on tells you the hand.

Levers are what you want on almost any commercial opening. A lever can be operated with a closed fist or an elbow, which is why they are standard on accessible routes, while a round knob requires grasping and twisting. The C550 is a lever lockset in three designs. If you are replacing knobs on a building-wide basis, a knob equivalent in the same entrance/office function is the Marks USA 110AB entry knob lockset, Grade 2, though it uses a 2-3/8 inch backset rather than 2-3/4.

For a keyed opening on a conventional cylinder, the D version arrives as a complete single-cylinder lock with the 15250 latch and 5001 ANSI strike. The SFIC J version ships less core, so you need to supply or order a small format interchangeable core separately or the lock cannot be keyed. Beyond that, if the frame is not already prepped for the 1-1/4 x 4-7/8 inch ANSI strike, budget for frame work.

The C500 Series covers ten different functions, so the matching passage, privacy and storeroom locks come from the same family and share the lever designs and finishes. If you are sourcing across brands instead, the Orca Hardware OCL210 passage and OCL240 privacy cylindrical locksets are both Grade 2 medium duty, and the Cal-Royal CAL30 passage and CAL20 privacy locks are Grade 1 fitting 1-3/8 to 2 inch doors. Mixing brands means the levers and roses will not visually match the C550.

Not on the same door prep. The 110AB matches the C550 on grade and function - both are Grade 2 in an entrance/office function - but the 110AB is a round knob lockset on a 2-3/8 inch backset, while the C550 is a lever on a 2-3/4 inch backset. Swapping between them means the bore centerline moves, and the knob trim will not satisfy an opening where lever operation is required for accessibility.

The C550 is an entrance/office function, which is not a classroom or classroom intruder function. For a classroom opening, the TownSteel FCE-2000 is a Grade 1 heavy duty standalone motorized cylindrical lockset with RFID in a classroom function; the FCE-4000 and XCE-9000 are the classroom intruder versions, the XCE-9000 with a keypad. The Schlage XE360M is a Grade 1 wireless tubular lock with an offline push button function for classroom and storeroom openings.

The C550 adjusts for doors 1-3/8 inch to 1-3/4 inch. For thicker leaves, the Cal-Royal Calypso series covers 1-3/8 inch to 2 inch: the CAL20 is a Grade 1 extra heavy duty privacy lock and the CAL30 is the Grade 1 passage version. On the keyed side, the Kwikset 912TNL SmartCode electronic Tustin lever also spans 1-3/8 inch to 2 inch in a keyed-one-side function.

Close on function, different on prep. The Stanley QCL200 is a cylindrical lock supplied keyed different with an SC keyway and a 118F ANSI 1-1/8 inch by 2-3/4 inch strike. The C550 ships with a 5001 ANSI 1-1/4 inch by 4-7/8 inch square corner strike, so the frame cutouts are not the same - an existing C550 frame prep will not take the QCL200 strike without rework, and the reverse holds too.

The Lockey mechanical pushbutton locks run without power. The Lockey 1600 is a heavy duty mechanical keyless knob lock with an adjustable backset, and the 2830 is a mechanical pushbutton keyless knob lock with an auto-locking passage function; both fit doors 1-1/8 inch to 2 inch. Both are knob trim rather than the lever trim on the C550, and neither is keyed the way the C550's single cylinder is - access is by code at the door.

The C550 is a mechanical keyed single cylinder lockset with no electrical provision. For a hardwired opening, the SDC Electra 7200 is a solenoid controlled cylindrical lock running dual voltage 12/24VDC, for doors 1-3/4 inch to 2 inch. For credential access without running wire, the Schlage NDEB is a Grade 1 heavy duty ENGAGE series cylindrical lock with a 2.4 GHz Bluetooth Low Energy reader, for doors 1-5/8 inch to 2 inch. Both need thicker doors than the C550's 1-3/8 inch minimum.

An optional patented key system is available on the C500 Series. On the SFIC less core version you can also drop in whatever restricted small format core your facility already runs, which is the usual route for a property manager standardizing keying across a building without changing lock hardware.

A dummy trim, not a lockset. The Orca Hardware OCL2170 is a Grade 2 half dummy lever in a medium duty chassis - it mounts a lever with no latch and no key. The C550 is a keyed entrance/office lockset and has no dummy function, so pair the working openings with the C550 and the inactive ones with the half dummy.

Function and grade. The 195N is a Grade 1 Survivor Series passage lever lockset with an American lever and is ADA compliant - it latches but never locks. The C550 is a Grade 2 keyed entrance/office lockset with a single cylinder. On a floor where some doors need to lock and some do not, the C550 covers the keyed openings and the 195N covers the corridor and closet doors.