BEST 8K Series Communicating F...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$1,004.00
$557.78
BEST BEST 8K Series - Communicating Function (S) Double Cylinder Grade 1 Heavy Duty Knob Lock, SFIC Less Core BEST-8K-S

BEST 8K Series Communicating Function Double Cylinder Grade 1 Heavy Duty Knob Lock

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Model: 8K37S4ASTK612
$1,004.00
$557.78
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In Stock (leaves warehouse same day if ordered before 3pm ET)

$1,004.00
$557.78
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BEST 8K Series Communicating Function Double Cylinder Grade 1 Heavy Duty Knob Lock

Premium Grade 1 Cylindrical Knob Lock for Heavy-Duty Commercial Applications

The BEST 8K Series delivers dependable security for high-traffic commercial environments with Grade 1 heavy-duty construction. This communicating function double cylinder knob lock features knobs machined from solid brass or bronze bar stock with a 2 1/16" diameter chassis designed to fit 2 1/8" door holes. The 9/16" throw deadlocking latch provides reliable security, while the adjustable door thickness accommodation from 1 3/8" to 2" ensures versatile installation compatibility.

Professional Features & Benefits

  • Grade 1 Heavy-Duty Construction: Exceeds ANSI Grade 1 requirements for security and reliability in demanding commercial applications.
  • Solid Machined Knobs: Knobs machined from solid brass or bronze bar stock provide exceptional durability and premium feel with 2 1/8" diameter and 2 7/8" projection from door.
  • Adjustable Door Compatibility: Standard adjustment from 1 3/8" to 2" door thickness with special E trim available for 2 1/8" to 3" doors.
  • Enhanced Security Features: Cores must be removed before keyed knobs to deter break-in attempts, with snap-on inside rose featuring no exposed screws for tamper resistance.
  • Deadlocking Latch System: 9/16" throw deadlocking latch with 2 1/4" x 1 1/8" beveled front fits 1" hole in door edge for secure engagement.
  • Smooth Operation Design: Steel retractor with low friction bearings and long bearing length in chassis ensures smooth, wear-resistant operation throughout the lock’s service life.
  • Rotating Knob Face: Allows easy hand of door change without removing the knob, simplifying installation and reconfiguration.
  • Corrosion-Resistant Components: Internal parts are brass or corrosion-treated steel for long product life in demanding environments.

Technical Specifications

  • Commercial/Residential: Commercial
  • Department: Door Hardware
  • Door Hand Direction: Non-Handed
  • Duty Level: Heavy Duty
  • Electronic: No
  • Grade: Grade 1
  • Handle Type: Knob
  • Keyed: No
  • Keyed Function: Double Cylinder
  • Product Attribute: Cylindrical Locks
  • Product Category: Mechanical Locks
  • Product Function: Communicating
  • Product Group: Mechanical Locks
  • Product Subgroup: Bored Locksets
  • Product Type: Knobsets
  • Series: 8K Series
  • Subcategory: Bored Locksets

Installation & Operation

  1. Review manufacturer specifications and verify door preparation requirements including door thickness from 1 3/8" to 2" and 2 1/8" bore hole for lock housing.
  2. Use manufacturer-provided templates to mark mounting hole locations accurately including 1" hole for latch tube in door edge.
  3. Prepare door and frame by drilling required holes including 2 1/8" diameter bore for chassis and routing as specified in manufacturer instructions.
  4. Install all mounting hardware and secure the device to door and frame per manufacturer torque specifications, ensuring proper rose threading to chassis.
  5. Adjust operational components for proper alignment, latching, and smooth operation throughout the full range of motion, utilizing the rotating knob face feature for hand changes if needed.
  6. Test device operation to verify proper function and make final adjustments as needed. Refer to manufacturer documentation for complete installation details and troubleshooting.

Professional Applications

  • Government and Military Facilities
  • Commercial Office Buildings
  • Educational Institutions
  • Healthcare Facilities
  • Industrial and Warehouse Buildings
  • Multi-Tenant Residential Properties
  • International Projects Without ADA Requirements

Why Choose BEST Quality?

BEST 8K Series knob locks deliver professional-grade reliability with solid brass or bronze construction and Grade 1 certification that exceeds ANSI requirements for security and durability. The premium workmanship and carefully designed components ensure long-term performance in high-traffic commercial applications. Engineered for demanding environments where dependable security and smooth operation are essential for years of reliable service.

Product Specs

Series:
8K Series
Grade:
Grade 1
Duty Level:
Heavy Duty
Keyed Function:
Double Cylinder
Product Group:
Mechanical Locks
Product Subgroup:
Bored Locksets
Product Type:
Knobsets
Subcategory:
Bored Locksets
Keyed:
No
Electronic:
No
Commercial/Residential:
Commercial
Handle Type:
Knob
Product Attribute:
Cylindrical Locks
Product Function:
Communicating
Door Hand Direction:
Non-Handed
Product Category:
Mechanical Locks
Department:
Door Hardware

BEST 8K37S4ASTK612 – Frequently Asked Questions

1) What does the communicating function on a BEST 8K knob lock actually do?
Communicating function means a key is required from both sides. The BEST 8K in this configuration is a double cylinder knob lock, so there is a cylinder in each knob and no free egress from either side. That is what you want between two rooms that both need to be secured from the other, and it is the reason this one is not a drop-in for an entry or office opening where the inside knob must always turn free. If you need key outside and always-free inside, a storeroom or entrance/office function is the right pick instead, such as the Sargent 8XG04 Grade 1 storeroom knob lock.
2) Can I put a BEST 8K knob lock into an existing 2-1/8 inch bored door without new prep?
If the door already has the standard cylindrical prep, yes. The 8K chassis measures 2-1/16 inches and drops into a 2-1/8 inch bore, with a 1 inch hole in the edge for the latch. Check the backset before you order: the 8K is offered in 2-3/4 inch standard and 5 inch. Most commercial bored doors are 2-3/4 inch, and 2-3/8 inch is the common residential backset, so a house-style prep will not line up.
3) Does the BEST 8K knob lock come with cores, or do I need to order them separately?
It ships less core. The 8K takes BEST small format interchangeable cores, and because this is a communicating double cylinder function, you need two cores per lock, one for each knob. Order the cores in your facility's keyway alongside the lock. Note for servicing: the core has to come out before a keyed knob can be removed, which is a deliberate anti-attack feature, not a fault.
4) Is a knob lock like the BEST 8K acceptable on an ADA opening?
No. A round or tulip knob requires grasping and twisting, so knobs are not the choice where accessible operation is required, and BEST positions the 8K for commercial work including international projects without ADA requirements. Where the opening has to be accessible, specify a lever instead. Knobs still make sense on doors exempt from that requirement, in secure areas, and where a lever would be a pull hazard.
5) What is the closest Grade 1 heavy duty cylindrical knob lock to the BEST 8K Series if I need a keyed storeroom function instead of communicating?
The Sargent 8XG04 is a Grade 1 heavy duty storeroom/closet knob lock with a single cylinder and a 2-3/4 inch backset. The BEST 8K in communicating function is a double cylinder lock, keyed on both sides of the opening, and it is offered in 2-3/4 inch and 5 inch backsets. Use the 8XG04 where one side is a keyed outside knob and the inside knob always retracts the latch; use the 8K communicating where both faces of the door need a cylinder, as on a pair of connected rooms.
6) Is the Sargent 6G04 knob lock an acceptable substitute for a BEST 8K Series opening?
The Sargent 6G04 is a Grade 2 standard duty storeroom knob lock with a single cylinder. The BEST 8K Series is Grade 1 heavy duty with a double cylinder communicating function. If the specification on the drawing calls for ANSI/BHMA Grade 1, the 6G04 does not meet it, and a single cylinder lock will not key both faces of a communicating door. The 6G04 suits a closet or storage door in a lower traffic count where Grade 2 is accepted.
7) Which Grade 1 knob lock should be used on the adjacent corridor door where no keying is wanted?
The Falcon X101 is a Grade 1 heavy duty cylindrical passage knobset with an interchangeable core provision and a fire rating, fitting doors 1-3/8 inch to 2-1/4 inch. The Schlage D10S is a Grade 1 heavy duty cylindrical passage latch with an Orbit knob. Either holds Grade 1 on a latch-only opening, while the BEST 8K communicating function is a keyed double cylinder lock intended for the door that has to be secured from both rooms. A common approach is 8K on the connecting door and a Grade 1 passage set on the corridor leaf.
8) Which knob products look like a substitute for a cylindrical knob lock but are actually trim only?
Several knob items are trim rather than a complete bored lockset. The Sargent 28C-KNOB is exit device trim with knob and rose in entrance function for 1-3/4 inch doors, the Sargent 78-2875 is an outside knob only with B design, and the Imperial USA ED-BKL580 is knob trim in storeroom function. Those mount to an exit device or replace a knob on existing hardware. The BEST 8K Series is a complete cylindrical lockset with its own chassis, latch and strike.
9) Why would I order the 5 inch backset on a BEST 8K knob lock?
A 5 inch backset is for doors with a wide stile or a rail that pushes the lock further off the edge, or where the knob would otherwise sit too close to a frame, mullion or adjacent surface. The 8K offers 2-3/4 inch as standard and 5 inch as the alternative. Measure from the door edge to the centerline of the existing bore before ordering; a 5 inch chassis will not reach a 2-3/4 inch prep.
10) Do I have to specify handing when ordering a BEST 8K knob lock?
No. The 8K is non-handed, and the knob face rotates so the hand of door can be changed without pulling the knob off. One part number covers left and right hand openings, which is why property managers standardizing across a building can stock a single lock instead of two.
11) Which rose and knob style should I pick for a BEST 8K to match the rest of my building?
Knob style is round or tulip, and there are four roses: 2-9/16 inch concave, 3-3/8 inch concave, 3-3/8 inch concave for thick doors, and 3-3/8 inch convex. The larger 3-3/8 inch roses cover more of the door face, which helps when you are replacing an older lock that left a wider mark or a bigger prep. The inside rose snaps on with no exposed screws.
12) What is a good Grade 1 knob lock alternative to the BEST 8K if I do not need a key on both sides?
Depends which side you want free. For key outside and always-unlocked inside, the Sargent 8XG04 is a Grade 1 heavy duty storeroom knob lock with a 2-3/4 inch backset and a single cylinder. For no key at all, the Schlage D10S is a Grade 1 heavy duty passage knob, and the Falcon X101 is a Grade 1 heavy duty passage knobset with an interchangeable core that fits 1-3/8 to 2-1/4 inch doors. The Corbin Russwin CK4851 is a keyed entrance/office cylindrical knob lock covering 1-3/8 to 2 inch doors.
13) What Corbin Russwin knob lock lines up with the BEST 8K Series on door thickness?
The Corbin Russwin CK4310 passage/closet cylindrical lock is Grade 1 with a Global knob and covers 1-3/8 inch to 2 inch doors, the same range the BEST 8K Series adjusts to in its standard configuration. The CK4310 is non-keyed passage; the 8K in communicating function is keyed on both sides. The CK4410 is the Grade 2 counterpart and covers 1-3/8 inch to 1-3/4 inch, so it stops short of the 2 inch door.
14) Can a Dexter C2000 or Kwikset Polo knob be used where a BEST 8K Series was specified?
The Dexter C2000 knob locks are Grade 2, non-clutching, for 1-3/8 inch to 1-3/4 inch doors, in classroom, entry/office, passage and privacy functions. The Kwikset 400P-CP Polo keyed entry knob is Grade 3 for 1-3/8 inch to 1-3/4 inch doors. The BEST 8K Series is Grade 1 heavy duty commercial. Those Grade 2 and Grade 3 sets belong on lighter openings and neither offers the double cylinder communicating function, so they are not a like-for-like answer to an 8K specification.
15) Is a dummy knob a substitute for a BEST 8K Series knob lock on an inactive leaf?
No. Dummy sets such as the Schlage A170 single dummy trim, the Cal-Royal BA40 dummy knob, the Bravura Biloxi dummy knobset and the Omnia 442/00 single dummy have no latch and no cylinder; they are surface trim for an inactive leaf or a closet face. The BEST 8K Series has a 9/16 inch throw deadlocking latch and double cylinder keying. On a pair of doors, the dummy goes on the inactive leaf and the 8K on the active one.
16) What should be used instead of a BEST 8K Series on a fire rated opening that needs a documented fire rating?
The Falcon X101 Grade 1 heavy duty cylindrical passage knobset carries a fire rating, and the Falcon W101 Grade 2 medium duty passage/closet knob lock with a 2-3/4 inch backset also carries one. The BEST 8K Series in communicating function is a Grade 1 heavy duty double cylinder lock; a communicating function keys both faces, which is a different security arrangement than a passage latch. Confirm the door and frame label requirements with the authority having jurisdiction before selecting between them.
17) What is the alternative to the BEST 8K Series for a bed or bath door that needs privacy rather than keying?
Privacy knob locks in the set include the Cal-Royal BER20 Grade 3 privacy knob lock with brass trim for 1-3/8 inch to 1-3/4 inch doors, the Dexter C2000 Grade 2 privacy knob lock for the same thickness range, the Pamex FTF Grade 3 Baron privacy lockset, and the Deltana 6112 St. Thomas privacy knob for 1-3/8 inch to 2 inch doors. Those lock from inside without a key. The BEST 8K communicating function uses cylinders on both sides, which is what a connecting patient or office door usually requires instead.
18) How do the BEST 8K Series and the Corbin Russwin CK4851 compare for a keyed office door?
The Corbin Russwin CK4851 is a Grade 1 entrance/office cylindrical lock with a Global knob and a conventional cylinder, for 1-3/8 inch to 2 inch doors. The BEST 8K Series is Grade 1 heavy duty in communicating function with a double cylinder, adjusting 1 3/8 inch to 2 inch as standard. The CK4851 keys one side for an office entry; the 8K keys both sides, which is what a door between two controlled rooms calls for. Cylinder type is the other decision point: the CK4851 takes a conventional cylinder.
19) For a facility standardizing knob hardware across many doors, how does the BEST 8K Series differ from the Arrow MK01 and RK01?
The Arrow MK01 and RK01 are Grade 2 passage/hall/closet cylindrical knob locks for 1-3/8 inch to 1-3/4 inch doors, the RK01 with a ball knob. The BEST 8K Series is Grade 1 heavy duty for commercial use, non-handed, and comes in ten finishes including 626AM satin chrome antimicrobial, with round and tulip knob styles and a choice of ANSI or standard strike. A facility standardizing on Grade 1 across secured openings would carry the 8K there and can use the Grade 2 Arrow sets on latch-only doors.
20) Is the Lockey 3830 keyless combination knob lock an option where a BEST 8K Series would go?
The Lockey 3830 is a mechanical keyless combination knob lock with an auto-locking passage function for doors 1 3/16 inch to 2 inch. It controls access by code rather than by key. The BEST 8K Series is a keyed double cylinder communicating lock and carries no electronics. Choose the 3830 where the goal is to avoid issuing keys entirely; choose the 8K where the opening has to sit inside an existing key system on both faces.
21) Are residential knobsets like the Baldwin Estate or Schlage F Series comparable to the BEST 8K Series?
They serve different openings. The Baldwin Estate 5000 Baltimore knob comes preconfigured in passage and privacy with a 2-3/8 inch backset and a full lip strike, and the Schlage Residential F500 Plymouth with Georgian knob is a combo pack with adjustable backsets and dual strikes for 1-3/8 inch to 1-3/4 inch doors. The BEST 8K Series is Grade 1 heavy duty commercial with 2-3/4 inch and 5 inch backsets. On a commercial corridor or a government or healthcare opening, the 2-3/8 inch residential backset will not match the door prep the 8K is built for.
22) What finishes does the BEST 8K knob lock come in, and is there an antimicrobial option?
Ten finishes: 605 bright brass, 606 satin brass, 611 bright bronze, 612 satin bronze, 613 satin bronze oil-rubbed, 619 satin nickel, 625 bright chrome, 626 satin chrome, 626AM satin chrome antimicrobial, and 690 statuary dark bronze. The 626AM is the one to specify for healthcare and other high-touch environments where an antimicrobial coating is called for.
23) How far does a BEST 8K knob stick out from the door face?
The knob projects 2-7/8 inches from the door and is 2-1/8 inches in diameter. That projection matters in tight corridors, next to a return wall, or where a door swings against adjacent hardware, so check your clearance before committing on a narrow opening.
24) Will a BEST 8K knob lock hold up in a coastal or humid facility?
Internal parts are brass or corrosion-treated steel, and the knobs themselves are solid brass or bronze bar stock. That construction is aimed at long service life in demanding environments. For exterior or wash-down areas, the plated finishes such as 626 satin chrome and 690 statuary dark bronze are the usual specification over the bright brass options.
25) What is the simpler option if a full BEST 8K Series lock is more than a storage or closet door needs?
For a latch-only closet or hall door, the Pamex FTF Grade 3 Baron passage lockset and the Bravura Albany or Lynchburg Grade 2 passage knobsets cover it, as does the Cal-Royal BER00 Grade 3 entrance/office knob lock with a Kwikset keyway where a simple key is wanted. All three Pamex and Cal-Royal sets are for 1-3/8 inch to 1-3/4 inch doors. The BEST 8K Series is the Grade 1 heavy duty choice, keyed on both faces, for the openings that actually carry the traffic and the security requirement.
26) Do decorative knobsets such as Emtek or Omnia work as a replacement for a BEST 8K Series?
They address appearance rather than a Grade 1 security requirement. The Emtek Porcelain knobs ship as two knobs per set with a threaded rod, and the Emtek Arts and Crafts Hammered Egg and Classic Brass Crystal Georgetown and Providence sets are dummy pairs. The Omnia 434/PA is a passage latchset with a 3 inch projection in solid brass. The BEST 8K Series is a keyed commercial lock with knobs machined from solid brass or bronze bar stock and a 2 7/8 inch projection from the door, offered in ten finishes.
How fast can I get the BEST 8K37S4ASTK612 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 BEST 8K37S4ASTK612 come with a warranty?
Absolutely. The BEST 8K37S4ASTK612 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 BEST 8K37S4ASTK612?
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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