BEST 8K Series Grade 1 Heavy D...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$971.00
$561.02
BEST BEST 8K Series - Storeroom Function (G) Double Cylinder Grade 1 Heavy Duty Knob Lock, SFIC Less Core BEST-8K-G

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

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Model: 8K37G4ASTK690
$971.00
$561.02
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In Stock (leaves warehouse same day if ordered before 3pm ET)

$971.00
$561.02
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BEST 8K Series Grade 1 Heavy Duty Storeroom Function Double Cylinder 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 storeroom 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: Accommodates door thickness from 1 3/8" to 2" standard, with special E trim available for 2 1/8" to 3" doors.
  • Enhanced Security Design: 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 latching.
  • Smooth Operation: Steel retractor with low friction bearings and long bearing length in chassis ensures smooth, wear-resistant operation throughout the lock's service life.
  • Quick Rekeying Capability: BEST interchangeable core system allows economical rekeying without lock replacement for efficient key management.
  • Corrosion-Resistant Components: Internal parts are brass or corrosion-treated steel with brass or bronze roses reinforced with steel liner for long-term durability.

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: Storeroom
  • 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 (1 3/8" to 2" standard), 2 1/8" bore hole, and 1" edge hole for latch housing.
  2. Use manufacturer-provided templates to mark mounting hole locations accurately on door and frame surfaces for proper chassis and strike plate positioning.
  3. Prepare door by drilling 2 1/8" diameter hole for chassis and 1" hole in door edge for latch housing per manufacturer specifications.
  4. Install chassis, latch assembly, and strike plate using appropriate mounting hardware and secure per manufacturer torque specifications.
  5. Adjust knob operation and latch alignment for proper function, ensuring 9/16" throw deadlocking latch engages securely with strike plate.
  6. Test lock operation to verify proper function of both keyed and non-keyed sides, 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 (Non-ADA Compliant Regions)

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 demanding commercial applications where dependable security is essential. Engineered for high-traffic environments with corrosion-resistant internal components and smooth-operating steel retractor systems for lasting functionality.

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:
Storeroom
Door Hand Direction:
Non-Handed
Product Category:
Mechanical Locks
Department:
Door Hardware

BEST 8K37G4ASTK690 – Frequently Asked Questions

1) Will the BEST 8K Series knob lock fit my existing 2-1/8 inch door bore?
Yes. The 8K chassis measures 2-1/16 inches in diameter and drops into a standard 2-1/8 inch cross bore, with a 1 inch hole in the door edge for the latch housing. That is the normal commercial prep, so on a door already bored for a cylindrical lockset you are usually installing into existing holes rather than drilling fresh ones.
2) What does storeroom function mean on the BEST 8K, and is the inside knob always free?
Storeroom function means the outside knob stays locked at all times and is retracted only by the key. The inside knob is always free for egress, so nobody gets shut in. The door relocks behind you every time, which is why this is the function specified for mechanical rooms, supply closets, IT rooms and anything that must never be left unsecured by accident. If you want an office door that can be left unlocked for the day, storeroom is the wrong function.
3) Does the BEST 8K knob lock come with a core, and what keyway do I get?
The 8K ships less core. It takes a BEST small format interchangeable core, which you order separately keyed to your existing system, so the lock goes on the door and your locksmith drops in a core on your master key. That is the point of the SFIC design: rekeying later is a core swap, not a lock replacement.
4) Is a 2-3/4 inch or 5 inch backset right for a BEST 8K knob lock?
Backset is the distance from the door edge to the center of the bore. The 8K is offered at 2-3/4 inches, which is the standard commercial backset and what almost every hollow metal or commercial wood door is prepped for, and at 5 inches for wide stile aluminum and narrow-frame applications where the bore sits further in from the edge. Measure the existing hole before ordering; a 5 inch backset lock will not reach a 2-3/4 inch prep.
5) What do I have to specify when ordering a BEST 8K storeroom knob lock?
Five choices decide the part: backset (2-3/4 or 5 inch), knob style (round or tulip), rose (2-9/16 inch concave, 3-3/8 inch concave, 3-3/8 inch concave thick door, or 3-3/8 inch convex), strike (ANSI or standard), and finish. Order the core separately. If you are matching other openings in the building, the rose diameter and knob style are what people notice, so copy those off an existing door.
6) Should I use a knob lock or a lever for a storeroom door, and does the BEST 8K meet ADA?
A knob takes a tight grasp and twist to operate, so on any opening on an accessible route in the US you want a lever instead. The 8K is specified for commercial work where a knob is acceptable, including international projects in non-ADA regions, back-of-house and mechanical spaces. If the door is on an accessible path, choose a lever lockset rather than this knob.
7) What is the closest Grade 1 heavy duty storeroom knob lock to the BEST 8K Series?
The Sargent 8XG04 is the nearest match. Both are Grade 1 heavy duty storeroom function cylindrical knob locks, and the 8XG04 is offered with a 2-3/4 inch backset, which is the standard backset on the BEST 8K as well. The difference to check before ordering is keying: the 8XG04 is a single cylinder storeroom lock, while the 8K Series is built for the BEST interchangeable core system with a double cylinder keyed function. If a facility is already keyed to a BEST SFIC system, the 8K keeps that keying scheme intact; if the opening is on a conventional Sargent system, the 8XG04 drops into it.
8) What Grade 1 knob lock should I use on the openings that need to stay unlocked?
Storeroom function keeps the outside knob locked at all times, so it is the wrong choice for a corridor or closet door that should always push open. For those openings the Falcon X101 is a Grade 1 heavy duty cylindrical passage knobset with an interchangeable core, and the Schlage D10S is a Grade 1 heavy duty passage latch knob lock with an Orbit knob. The Falcon X101 accommodates doors from 1-3/8 to 2-1/4 inches, against 1-3/8 to 2 inches on the BEST 8K Series with standard trim. Specifying the X101 alongside the 8K keeps the whole opening set on Grade 1 heavy duty chassis with the storeroom doors keyed and the passage doors free.
9) Which knob lock do I put on a classroom or an office door instead of a storeroom lock?
A storeroom lock has no way to leave the outside knob unlocked, which is why offices and classrooms take a different function. The Corbin Russwin CK4851 is a Grade 1 entrance/office cylindrical lock with a Global knob and a conventional cylinder, fitting doors 1-3/8 to 2 inches, the same door range the BEST 8K Series covers with standard trim. For a classroom that is locked and unlocked from the outside by key, the Dexter C2000 Series classroom ball knob lock is a Grade 2 keyed classroom function for doors 1-3/8 to 1-3/4 inches. Both are cylindrical knob locks like the 8K, so the door prep thinking is the same; the function is what changes.
10) Can I substitute the Imperial USA ED-BKL580 storeroom knob trim for a BEST 8K knob lock?
No. The Imperial USA ED-BKL580 is knob trim in the ED-500 Series with a storeroom function, meaning it mounts to an exit device and has no lock chassis of its own. The Sargent 28C-KNOB is the same kind of part, exit device trim with a knob and rose sized for 1-3/4 inch doors, and the Sargent 78-2875 is an outside knob only. The BEST 8K Series is a complete cylindrical lockset with its own 2 1/16 inch chassis, deadlocking latch and strike, prepped into a 2 1/8 inch bore. Trim matched to an exit device cannot be installed in that bore, and the 8K cannot be hung on a rim device.
11) 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 matters for healthcare and food service, where a touched surface with an antimicrobial coating is often written into the spec. 626 satin chrome is the usual commercial default if you are matching existing hardware.
12) Is the BEST 8K knob lock Grade 1, and is it strong enough for a high traffic building entrance?
Grade 1, heavy duty, and built for commercial service: knobs machined from solid brass or bronze bar stock, brass or corrosion-treated steel internals, roses reinforced with a steel liner, and a steel retractor riding on low friction bearings. That combination is what carries it through high cycle counts on schools, hospitals and government buildings.
13) I do not need a keyed storeroom lock on every door. What else works with the same prep?
For a passage or closet door where nothing needs to lock, the Falcon X101 is a Grade 1 heavy duty cylindrical passage knobset that also takes an interchangeable core and covers 1-3/8 to 2-1/4 inch doors, or the Corbin Russwin CK4310 Grade 1 passage knob for 1-3/8 to 2 inch doors. Both are the non-keyed counterparts at the same duty level, so you can mix them through a building without dropping to a lighter grade on the doors that matter less.
14) Is a Grade 2 storeroom knob like the Sargent 6G04 a fair substitute for the BEST 8K?
Not on a high traffic opening. The Sargent 6G04 is a Grade 2 standard duty storeroom knob lock with a single cylinder, which suits a light-use closet, but the 8K is Grade 1 heavy duty with solid bar stock knobs and steel-reinforced roses. If the spec on the drawing calls Grade 1, a Grade 2 lock will not pass, and on a door cycled hundreds of times a day the lighter chassis is where you will see the wear first.
15) How secure is the BEST 8K against someone attacking the knob or the screws?
Two things work in your favor. The core has to come out before the keyed knob can be removed, so pulling the knob does not get an attacker into the chassis. And the inside rose snaps on with no exposed screws, so there is nothing to back out from the secure side. The latch also deadlocks at 9/16 inch throw, which resists a card or shim slipped at the strike.
16) What Grade 1 knob lock matches the BEST 8K on a thick door?
With standard trim the BEST 8K Series takes doors from 1 3/8 to 2 inches, and special E trim carries it to 2 1/8 to 3 inches. Among the Grade 1 knob locks, the Falcon X101 passage knobset is rated 1-3/8 to 2-1/4 inches, and the Corbin Russwin CK4310 Grade 1 passage/closet knob lock is rated 1-3/8 to 2 inches. Both of those are passage function, so on a thick door that must stay locked, the 8K with E trim is the storeroom answer, and a rose ordered as 3-3/8 inch concave thick door goes with it.
17) Is there a lighter duty storeroom knob lock for a lower traffic opening?
The Sargent 6G04 is the standard duty option. It is a Grade 2 storeroom/closet knob lock with a single cylinder, from the 6 Line Series. The BEST 8K Series is Grade 1 heavy duty with a double cylinder keyed function. For a storage closet on a back corridor that sees a few cycles a day, the Grade 2 6G04 covers the same storeroom function; for a main stock room or a mechanical room on a high traffic run, the Grade 1 8K is the heavier chassis.
18) Will a Kwikset or Master Lock keyed knob work in place of a BEST 8K storeroom lock on a commercial door?
They are built for a different service level. The Kwikset 400P-CP Polo keyed entry knob is Grade 3 for doors 1-3/8 to 1-3/4 inches, and the Master Lock BC Series biscuit knob keyed entry is also Grade 3. Both are entrance function, which unlocks from the outside with a turn or button, so a stock room would not stay secured. The BEST 8K Series is Grade 1 heavy duty commercial with a storeroom function that keeps the outside knob locked at all times, and it takes doors up to 2 inches with standard trim. On a tenant closet in a low traffic building a Grade 3 entrance knob is a knob lock; on a commercial storage or mechanical room it is not the same specification.
19) I need a keyless storeroom door with no key management. What is the alternative to the BEST 8K?
The Lockey 3830 is a mechanical keyless combination knob lock with an auto-locking passage function, fitting doors 1 3/16 to 2 inches. It requires no cylinder and no key issue, which suits a shared equipment room where staff turn over. The BEST 8K Series is a keyed storeroom lock built on the BEST interchangeable core system, which lets a facility rekey a whole run of openings by swapping cores rather than replacing locks, and it is Grade 1 heavy duty. Choose the 3830 when the goal is to eliminate keys entirely, and the 8K when the door has to belong to a master key system.
20) How far does the BEST 8K knob stick out from the door face?
The knob measures 2-1/8 inches in diameter with a 2-7/8 inch projection from the door. That projection matters where a door swings into a tight corridor, a wall return, or beside a frame-mounted device, and it is the number to check against a 2-9/16 inch or 3-3/8 inch rose when you are laying out hardware on a narrow opening.
21) Is a Grade 2 cylindrical knob lock an acceptable alternative to the BEST 8K for a commercial closet?
Several Grade 2 cylindrical knob locks cover closet and passage openings: the Corbin Russwin CK4410 passage/closet knob lock for doors 1-3/8 to 1-3/4 inches, the Falcon W101 medium duty passage/closet knob lock with a 2-3/4 inch backset and a fire rating, and the Arrow MK01 passage knob for doors 1-3/8 to 1-3/4 inches. All three are non-keyed passage function, so they suit a closet that does not need to lock. Where the closet holds stock or tools and must stay secured, the BEST 8K storeroom function with its 9/16 inch throw deadlocking latch is the specification that matches the requirement.
22) Are dummy knobsets like the Schlage A170 interchangeable with a BEST 8K knob lock?
No. The Schlage A170 is single dummy trim, a Grade 2 non-keyed knob with no latch, and the Cal-Royal BA40 is a dummy knob cylindrical lock for doors 1-3/8 to 1-3/4 inches. Dummy trim is surface applied to an inactive leaf and never retracts anything. The BEST 8K Series carries a working chassis with a 9/16 inch throw deadlocking latch and a beveled front that fits a 1 inch hole in the door edge, plus a strike. If an inactive leaf needs a knob to match a run of 8K openings, a dummy is the right part; it is not a replacement for the lock.
23) What replaces a BEST 8K storeroom knob on a restroom or bedroom door?
Storeroom function is keyed from the outside and is not a privacy lock, so a restroom takes a different lockset. The Dexter C2000 Series privacy ball knob lock is a Grade 2 non-keyed privacy function for doors 1-3/8 to 1-3/4 inches, and the Cal-Royal BER20 is a Grade 3 privacy knob lock with brass trim for the same door range. Both give the inside thumbturn a restroom needs. The BEST 8K Series stays on the storage, mechanical and tenant service doors where the outside knob must remain locked.
24) What is the difference between the BEST 8K Series and a decorative solid brass knob set from Emtek, Baldwin or Omnia?
They answer different questions. The Omnia 434/PA is a solid brass egg-shaped knob latchset with a 3 inch projection in passage function, the Baldwin Estate 5000 Baltimore knob is a passage lock with a 2-3/8 inch backset and a full lip strike, and the Emtek Porcelain knobs ship as two knobs per set with a threaded rod. Those are residential decorative sets built around finish and knob shape. The BEST 8K Series is a Grade 1 heavy duty commercial storeroom lock with knobs machined from solid brass or bronze bar stock, a 2 1/16 inch chassis, and a BEST interchangeable core for rekeying, offered in round and tulip knob styles across ten architectural finishes.
25) Which Grade 1 cylindrical knob locks can be ordered on the same interchangeable core system as the BEST 8K?
The Falcon X101 is a Grade 1 heavy duty cylindrical passage knobset offered with an interchangeable core, and it is fire rated for doors 1-3/8 to 2-1/4 inches. The BEST 8K Series storeroom lock also uses an interchangeable core, allowing rekeying without replacing the lock. Pairing them across a floor means the keyed storeroom doors and the free passage doors share a single core format for the locksmith, while the storeroom openings keep the requirement that cores be removed before keyed knobs.
How fast can I get the BEST 8K37G4ASTK690 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 8K37G4ASTK690 come with a warranty?
Absolutely. The BEST 8K37G4ASTK690 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 8K37G4ASTK690?
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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