Name: Corbin Russwin CK4351 Entrance/Office Cylindrical Lock - Grade 1, Global Knob, Keyed
Brand: Corbin Russwin
SKU: CK4351 GRD 605
Price: 716.18 USD
Availability: InStock

Product Overview
FAQs

Corbin Russwin CK4351-KEYED Entrance/Office Cylindrical Knobset - Grade 1, Global Knob, Keyed, 1-3/8" to 2" Doors

Heavy-Duty Commercial Cylindrical Lock for High-Use Institutional and Commercial Applications

The Corbin Russwin CK4351-KEYED Entrance/Office Cylindrical Knobset is a Grade 1 commercial-grade bored lockset engineered for demanding, high-use environments including schools, hospitals, hotels, and municipal buildings. Designed for doors ranging from 1-3/8" to 2" in thickness with a standard 2-3/4" backset, this knobset features a conventional 6-pin cylinder and ships with two nickel silver keys. The CK4300 Series delivers exceptional impact resistance through heavy wrought knobs lined with steel, while internal parts are zinc dichromate plated for corrosion resistance, making it a reliable choice for commercial, industrial, and institutional applications.

Professional Features & Benefits

Door Thickness Compatibility: Designed for 1-3/8" to 2" doors with a 2-3/4" backset, accommodating a wide range of standard commercial door preparations.
Grade 1 Commercial Performance: ANSI/BHMA Grade 1 rated (F109) for the most demanding commercial, industrial, and institutional applications where durability and reliability are critical.
Heavy-Duty Knob Construction: Heavy wrought knobs with steel liner provide exceptional impact resistance for high-traffic environments such as schools, hospitals, and airports.
Corrosion-Resistant Internal Components: Internal parts are zinc dichromate plated for corrosion resistance, extending service life in demanding conditions.
Deadlocking Latchbolt: Features a 1/2" (13mm) stainless steel throw deadlocking latchbolt operable by knob from either side, with a turn button that locks the outside knob requiring key entry to unlock.
Entrance/Office Function: Pushing the turn button locks the outside knob requiring key use; turning the inside knob unlocks the outside knob. A push-and-turn button position requires key at all times until manually returned to unlocked position, while the inside knob remains always free.
Standard Latch Included: Ships with a 787F66 deadlocking latch with 2-3/4" backset, square corner front, 2-1/4" x 1-1/8" universal configuration.
ANSI Curved Lip Strike Included: Includes an ANSI curved lip strike measuring 4-7/8" x 1-1/4" x 1-1/4" lip to center for standard door frame compatibility.
Conventional 6-Pin Cylinder: Equipped with a conventional 6-pin cylinder and two nickel silver keys for reliable keyed security.
Non-Handed Design: Non-handed configuration simplifies installation and reduces inventory requirements for commercial projects.
Manufacturer Warranty: Backed by a 3-year warranty for added confidence and protection.

Technical Specifications

Subcategory: Cylindrical Locks
Product Group: Mechanical Locks
Series: CK4300 Series
Grade: Grade 1
Keyed Function: Single Cylinder
Standard Latch: 787F66 - Deadlocking 2-3/4" Backset, Square corner front, 2-1/4" x 1-1/8" universal
Standard Strike: ANSI Curved Lip 4-7/8" x 1-1/4" x 1-1/4" lip to center
Warranty: 3 Year
ANSI/BHMA: F109
Product Subgroup: Bored Locksets
Product Type: Knobsets
Keyed: Yes
Fasteners: Wood and Machine Screws
Commercial/Residential: Commercial
Function Description: Deadlocking latchbolt by knob either side, except when turn button locks outside knob. Pushing turn button in locks outside knob, requiring use of key outside to unlock.
Lock Type: Cylindrical
Handle Type: Knob
Lock Function: Entrance/Office
Product Attribute: Cylindrical Locks
Product Model: CK4351
Product Function: Entrance/Office
Door Hand Direction: Non-Handed
Door Thickness Range: 1-3/8" to 2"
Product Category: Mechanical Locks
Backset (Distance): 2-3/4"
Department: Door Hardware

Installation & Operation

Review manufacturer specifications and verify door preparation requirements including door thickness (1-3/8" to 2"), backset (2-3/4"), stile width, and handing as applicable to this product.
Use manufacturer-provided templates to mark mounting hole locations accurately on door and/or frame surfaces.
Prepare door and frame by drilling required holes and routing as specified in manufacturer instructions. Install fasteners using the included wood and machine screws as appropriate for the door material.
Install the 787F66 deadlocking latch with 2-3/4" backset and secure the device to the door per manufacturer torque specifications.
Install the ANSI curved lip strike (4-7/8" x 1-1/4" x 1-1/4" lip to center) on the door frame, adjusting for proper latch engagement and alignment.
Test device operation to verify proper function of the turn button, inside knob, and keyed cylinder. Make final adjustments as needed. Refer to manufacturer documentation for complete installation details and troubleshooting.

Professional Applications

Schools and Educational Facilities
Hospitals and Nursing Homes
Hotels and Apartment Buildings
Municipal and Government Buildings
Airports and Transportation Facilities
Retail Complexes and Commercial Offices
Industrial and Warehouse Facilities

Why Choose Corbin Russwin Quality?

Corbin Russwin CK4300 Series cylindrical locks deliver professional-grade reliability with heavy wrought knobs lined with steel for impact resistance and zinc dichromate plated internal parts for corrosion resistance. The CK4351 meets ANSI/BHMA Grade 1 standards (F109) and is backed by a 3-year manufacturer warranty, providing confidence for the most demanding commercial and institutional applications. Engineered for high-use environments where dependable performance and long-term durability are essential.

Manufacturer Resources

Dummy Trim Knob Lock Installation Instructions

Product Specs

Subcategory:: Cylindrical Locks
Product Group:: Mechanical Locks
Series:: CK4300 Series
Grade:: Grade 1
Keyed Function:: Single Cylinder
Standard Latch:: 787F66 - Deadlocking 2-3/4" Backset, Square corner front, 2-1/4" x 1-1/8" universal
Standard Strike:: ANSI Curved Lip 4-7/8" x 1-1/4" x 1-1/4" lip to center
Warranty:: 3 Year
ANSI/BHMA:: F109
Product Subgroup:: Bored Locksets
Product Type:: Knobsets
Keyed:: Yes
Fasteners:: Wood and Machine Screws
Commercial/Residential:: Commercial
Function Description:: Deadlocking latchbolt by knob either side, except when turn button locks outside knob. Pushing turn button in locks outside knob, requiring use of key outside to unlock.
Lock Type:: Cylindrical
Handle Type:: Knob
Lock Function:: Entrance/Office
Product Attribute:: Cylindrical Locks
Product Model:: CK4351
Product Function:: Entrance/Office
Door Hand Direction:: Non-Handed
Door Thickness Range:: 1-3/8" to 2"
Product Category:: Mechanical Locks
Backset (Distance):: 2-3/4"
Department:: Door Hardware

Corbin Russwin CK4351 GRD 605 – Frequently Asked Questions

1) Will the Corbin Russwin CK4351 knob lock fit a 2 inch thick door?

Yes. The CK4351 cylindrical knobset covers 1-3/8 inch through 2 inch doors, which is wider than most bored locks reach at the top end. Standard commercial doors at 1-3/4 inches sit in the middle of that range, and older 1-3/8 inch interior doors are covered too. Backset is 2-3/4 inches, the usual commercial bore, so it drops into a standard 161 style prep.

2) How does the Entrance/Office function work on the Corbin Russwin CK4351?

Turn button in the inside knob does the locking. Push it in and the outside knob is locked, so the key is needed from the corridor side; turning the inside knob releases the button and unlocks the outside knob again. There is also a push-and-turn position that holds the lock on, meaning a key is required outside at all times until someone manually returns the button to unlocked. The inside knob is always free for egress, and the latchbolt operates by knob from either side whenever the button is out.

3) Do I have to order the CK4351 knobset handed for a left or right hand door?

No handing to specify. The CK4351 is non-handed, so one part number covers left and right hand openings in either swing. For a property manager or a facility stocking spares, that means a single lock on the shelf fits any door in the building rather than two.

4) Will the CK4351 latch work with the strike already in my frame?

It ships with an ANSI curved lip strike, 4-7/8 x 1-1/4 inches with a 1-1/4 inch lip to center, and a 787F66 deadlocking latch on a 2-3/4 inch backset with a square corner front measuring 2-1/4 x 1-1/8 inches. If your frame is already cut for a full ANSI 4-7/8 inch strike, the included strike drops straight in. If your existing prep is a small T-strike or a round corner residential strike, the frame needs to be modified or you keep the old strike and check that the deadlocking plunger rides on the strike face rather than falling into the cutout, otherwise the deadlocking feature is defeated.

5) What is the difference between the standard cylinder and the LC option on the Corbin Russwin CK4351?

Two cylinder choices. The standard is a conventional 6-pin cylinder in the L4 keyway, supplied with two nickel silver keys, ready to hang. LC is less conventional cylinder: the lock arrives without a cylinder so a locksmith can fit the facility's own cylinder and keyway. Order LC only if you already have cylinders on hand or a keying house supplying them, since the lock will not be operable by key as shipped.

6) Is a Grade 1 knob lock like the CK4351 worth it over a Grade 2 or Grade 3 entry knob?

For a school corridor, a hospital wing, or a municipal building the Grade 1 rating is the point. The CK4351 is ANSI/BHMA Grade 1, function F109, with heavy wrought knobs lined with steel and zinc dichromate plated internals for corrosion resistance. Lighter alternatives ZenSupply carries in the same Entrance/Office function include the Dexter C2000 entry/office knob at Grade 2 and the Pamex FTF Baron or Cal-Royal BER00 at Grade 3, which suit lower traffic interior openings. On a door being opened hundreds of times a day, the cycle life and impact resistance behind Grade 1 is what stops a callback.

7) I need a knob lock that stays locked from the outside at all times and cannot be left unlocked by a turn button. What should I order instead of the CK4351?

Use a storeroom function instead. The Sargent 8XG04 is a Grade 1 single cylinder storeroom/closet knob lock on a 2-3/4 inch backset, rated heavy duty, and the Sargent 6G04 is the Grade 2 storeroom version with a single cylinder. The CK4351 is an entrance/office lock: pushing the turn button locks the outside knob until a key is used, and turning the inside knob unlocks it again, so occupants can leave the door unsecured. A storeroom function removes that possibility because there is no turn button to leave in the unlocked position.

8) I have a classroom door and someone specified a CK4351. Is that the right function?

No. The CK4351 is an entrance/office lock, where the inside turn button controls the outside knob. For a classroom opening, the Dexter C2000 Series classroom ball knob lock is a Grade 2 keyed cylindrical knob lock built for classroom function, covering 1-3/8 inch to 1-3/4 inch doors, and the Sargent 28C-KNOB is a classroom function knob and rose trim for the 28 Series exit device on 1-3/4 inch doors. A classroom function is keyed from the outside only, which is why it is called out separately from entrance/office on drawings.

9) Can I substitute a Kwikset 400P Polo keyed entry knob for a Corbin Russwin CK4351?

They are not equivalents. The Kwikset 400P-CP Polo keyed entry knob is a Grade 3 entrance lock for 1-3/8 inch to 1-3/4 inch doors and ships with a round corner adjustable latch and round corner strike. The CK4351 is a Grade 1 commercial lock carrying ANSI/BHMA F109, fits 1-3/8 inch to 2 inch doors, and comes with a 787F66 deadlocking latch on a 2-3/4 inch backset with a square corner front plus an ANSI curved lip strike measuring 4-7/8 inches by 1-1/4 inches. If the frame is prepped for an ANSI strike and the door is prepped for a 2-3/4 inch backset, the Kwikset will not drop into that prep as supplied.

10) Can I get several CK4351 locks keyed alike so one key opens all of them?

Yes. Keying is a required selection: KD keyed different is the standard, and KA keyed alike ties multiple locks to a common key, which is what you want for a suite of offices or a set of tenant spaces run off one key. There is also a free text field for special cylinder or keying requirements if the job needs a specific keyway or a master key system tied into an existing building schedule.

11) Do I need to buy anything else to install a Corbin Russwin CK4351 knob lock?

The box covers the opening: lock, 787F66 deadlocking latch, ANSI curved lip strike, and both wood and machine screws so the same kit works on a wood door or a hollow metal one. What you supply is the door prep. A standard 2-1/8 inch cross bore on a 2-3/4 inch backset with a 1 inch edge bore is the normal cylindrical prep, and the frame needs to be cut for the 4-7/8 inch ANSI strike. On a keyed job you also decide keyed different or keyed alike at the time of order, since that is set in the cylinder.

12) Is a deadlocking latchbolt on an office lock actually worth having?

It is the difference between a door you can loid with a credit card and one you cannot. The CK4351 carries a stainless steel deadlocking latchbolt with a 1/2 inch (13mm) throw; the small auxiliary plunger beside the bolt rides the strike face and blocks the bolt from being pushed back once the door is closed. For a tenant office or a school administrative door that gets left locked overnight, that matters more than the knob itself. The 1/2 inch throw is why strike alignment is worth getting right, since there is not much bolt engaged in a misaligned frame.

13) I need matching passage and privacy knobs to go with a keyed office lock. What works?

The CK4351 is the keyed Entrance/Office function only, so hall, closet and restroom doors on the same corridor take different locks. Within heavy duty commercial knobs ZenSupply carries the Schlage D10S Grade 1 passage latch and the Falcon X101 Grade 1 passage knobset, which covers 1-3/8 to 2-1/4 inch doors. For lighter interior doors the Dexter C2000 range runs passage, privacy and classroom in Grade 2 on a matching ball knob, which keeps the look consistent across an office suite. Knob styling will not match the Corbin Russwin Global knob exactly across brands, so if appearance matters on a visible corridor, keep the whole opening group within one series.

14) Can the CK4351 be used as a classroom lock?

No, and the distinction matters for a school. Entrance/Office locking is done with a turn button on the inside knob, which means anyone inside can secure the door without a key. A classroom function lock is keyed from the outside only, with no inside button, so the room cannot be locked or unlocked from within. If the spec on the drawing calls for classroom, look at a classroom function lock such as the Dexter C2000 classroom knob rather than the CK4351.

15) Is there a lighter-duty entrance/office knob lock than the Corbin Russwin CK4351 for interior offices that do not need Grade 1?

Yes. The Dexter C2000 Series entry/office ball knob lock is a Grade 2 keyed cylindrical knob lock with the same entrance/office function, and the Pamex FTF Baron and Cal-Royal BER00 are Grade 3 knob locksets with an entrance/office function. All three cover 1-3/8 inch to 1-3/4 inch doors, where the CK4351 goes to 2 inches. The CK4351 is Grade 1 and carries the ANSI/BHMA F109 designation, which is what specifications for high-use openings normally call for.

16) What Grade 1 knob do I use on the corridor doors that are not supposed to lock at all, to match a CK4351 elsewhere in the building?

Use a Grade 1 passage knob. The Falcon X101 is a heavy duty Grade 1 cylindrical passage knobset that accepts an interchangeable core, is fire rated, and fits 1-3/8 inch to 2-1/4 inch doors; the Schlage D10S with the Orbit knob is a Grade 1 heavy duty passage latch. Both carry no cylinder and simply retract the latch from either side, while the CK4351 is keyed with a single cylinder. Keeping the passage doors at the same grade as the keyed CK4351 openings keeps one durability standard across the corridor.

17) For a restroom or private office that needs privacy rather than a key, what replaces a CK4351?

A privacy knob lock. The Dexter C2000 Series privacy ball knob is Grade 2 for 1-3/8 inch to 1-3/4 inch doors, the Pamex FTF Baron privacy knob and Cal-Royal BER20 are Grade 3 privacy locksets, and the Deltana 6112 St. Thomas privacy knob covers 1-3/8 inch to 2 inch doors like the CK4351 does. None of those are keyed; the CK4351 is a keyed single cylinder lock, so it is the wrong choice where you want the room locked from inside without issuing keys.

18) The CK4351 lists door thickness to 2 inches. What else covers a door that thick?

The Falcon X101 Grade 1 passage knobset goes from 1-3/8 inch to 2-1/4 inch, and the Deltana 3381 Egg, 6171 Round and 6112 St. Thomas knobs all cover 1-3/8 inch to 2 inch, the same range as the CK4351. Many alternatives stop at 1-3/4 inch, including the Dexter C2000 Series, Pamex FTF and Arrow MK01, so on a thick door the range is the first thing to check before the function.

19) We want to stop issuing keys on a back office door. Is there a keyless knob lock that fits the same door thickness as a CK4351?

The Lockey 3830 is a mechanical keyless combination knob lock with an auto-locking passage function, covering 1 3/16 inch to 2 inch doors, which spans the CK4351 range of 1-3/8 inch to 2 inch. It is operated by a code rather than the CK4351's conventional 6-pin cylinder and two keys. Keep in mind the CK4351 is Grade 1 with the ANSI/BHMA F109 designation, so if the opening was specified to that standard the keyless unit is a different specification, not a drop-in equal.

20) Will a Sargent 78-2875 outside knob or an Imperial ED-BKL580 knob trim work in place of a CK4351?

No. The Sargent 78-2875 is an outside knob only for the 7800 Series, and the Imperial ED-BKL580 is storeroom function knob trim for the ED-500 Series exit device. Both are trim that mounts to an exit device and depends on that device for latching. The CK4351 is a complete cylindrical bored lockset that ships with its own 787F66 deadlocking latch on a 2-3/4 inch backset and an ANSI curved lip strike. If the door has an exit device on it, you want the trim; if it has a standard 161 bored prep, you want the lockset.

21) What finishes does the Corbin Russwin CK4351 knobset come in?

Three: 605 bright brass, 613 satin bronze oil-rubbed, and 630 satin stainless steel. On institutional and commercial work 630 is the one that matches most existing hardware schedules; 605 and 613 are the choices where the opening is on a public or decorative side of the building. Each finish is offered with either the standard 6-pin conventional cylinder or the LC less cylinder version.

22) I need a matching knob on a door that only needs a pull, not a working latch. What goes with a CK4351?

That is dummy trim, not a lockset. The BEST 6K Series single dummy trim is a Grade 2 non-keyed cylindrical dummy knob, and the Schlage A170 single dummy trim is a Grade 2 heavy duty dummy knob for 1-3/8 inch to 1-7/8 inch doors. Neither has a latch or a cylinder; the CK4351 has a keyed single cylinder and a deadlocking latchbolt operated by the knob from either side. Dummy trim is what you order for the inactive leaf of a pair or a closet door held by a magnetic catch.

How fast can I get the Corbin Russwin CK4351 GRD 605 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 Corbin Russwin CK4351 GRD 605 come with a warranty?

Absolutely. The Corbin Russwin CK4351 GRD 605 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 Corbin Russwin CK4351 GRD 605?

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 Corbin Russwin CK4351 GRD 605 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.

Corbin Russwin CK4351 Entrance/Office Cylindrical Lock - Grade 1, Global Knob, Keyed

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