Corbin Russwin 421F25 Grade 1 ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$8.85
Corbin Russwin 421F25 ML2200 Machine Screw, 8-3 x 5/16

Corbin Russwin 421F25 Grade 1 ML2200 Machine Screw, 8-3 x 5/16

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Model: 421F25

In Stock (leaves warehouse same day if ordered before 3pm ET)

$8.85
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Corbin Russwin 421F25 ML2200 Series Machine Screw Replacement Part, 8-3 x 5/16

Genuine Corbin Russwin Replacement Screw for ML2200 Series Mortise Locks

The Corbin Russwin 421F25 is a genuine OEM machine screw replacement part designed specifically for use with the ML2200 Series Mortise Lock (Old). Sized at 8-3 x 5/16, this commercial-grade screw ensures a precise, secure fit when servicing or restoring ML2200 Series mortise lock hardware. Sourced directly from Corbin Russwin, this replacement component maintains the integrity and performance of your existing door hardware installation.

Professional Features & Benefits

  • ANSI/BHMA Grade 1 mortise lock per A156.13 Series 1000, Operational and Security Grade 1
  • UL Cycle above and beyond: 14.5 Million Cycles (Verification ID: V875753)
  • Patented Quick Reversible latchbolt — reverse handing without disassembling the lock case
  • Multi-function capability: 12 functions configurable from one ML2054 lockbody
  • Heavy-gauge steel lockcase 5-7/8" x 4" x 15/16"; 1" stainless steel deadbolt, 1" throw
  • 3/4" (19mm) throw anti-friction two-piece latchbolt requires less force to close
  • Wide variety of trim designs including Muséo®, Vineyard™, Behavioral Health (BHSS/BLSS)
  • Status indicator options for locked/unlocked visibility (sectional and escutcheon trim)
  • Motorized Electric Latch Retraction (MELR) available for ML20900 series
  • Thru-bolted trim designs for proper alignment and increased security
  • Can be used with new or existing Corbin Russwin key systems; accepts most other manufacturers' cylinders
  • UL/cUL listed, UL10C positive pressure; 3-hour fire door up to 4' x 10' single or 8' x 10' pair
  • Ten-year mechanical warranty; five-year MELR; two-year electrical

Technical Specifications

  • Grade: ANSI/BHMA A156.13 Series 1000, Operational and Security Grade 1
  • Handing: Handed; quick reversible — re-handed without disassembling the lock case
  • Door Thickness: 1-3/4" (44mm) standard; optional thicknesses available
  • Backset: 2-3/4" (70mm)
  • Lockcase: Heavy-gauge steel, 5-7/8" (149mm) x 4" (102mm) x 15/16" (24mm)
  • Armored Front: Wrought brass, bronze, or stainless steel, 8" x 1-1/4"
  • Latchbolt: 2-piece mechanical with anti-friction insert, 5/8" x 1" x 3/4" (19mm) throw
  • Auxiliary Latchbolt: 9/16" (14mm) effective throw; deadlocking
  • Deadbolt: One-piece stainless steel, 19/32" x 1-1/4" x 1" (25mm) throw
  • Strike: Wrought brass, bronze, or stainless steel, ANSI straight lip, 4-7/8" x 1-1/4" x 1-1/8" lip to center
  • Cylinder: Brass, 6-pin L4 keyway, 0-bitted standard
  • Spacing: C. to c. knob/lever to cylinder: 3-5/8" (92mm); knob/lever to thumbturn: 2-7/16" (62mm)
  • Certifications: ANSI/BHMA A156.13 Grade 1; UL/cUL UL10C 3-hour positive pressure; ADA A117.1; California State Fire Marshal; Windstorm/Hurricane certified
  • Warranty: Ten-year mechanical; five-year MELR; two-year electrical

Professional Applications

  • Commercial Office Buildings
  • Educational Facilities
  • Healthcare Institutions
  • Retail Establishments
  • Industrial and Warehouse Facilities
  • Multi-Tenant Residential Properties
  • Government and Municipal Buildings

Why Choose Corbin Russwin Quality?

Corbin Russwin lock parts and accessories are manufactured to exacting commercial-grade standards, ensuring reliable performance and precise compatibility with their respective hardware series. The 421F25 machine screw is a genuine OEM replacement component, purpose-built for the ML2200 Series Mortise Lock (Old) to preserve the integrity of your door hardware installation. When dependable, specification-matched replacement parts are essential, Corbin Russwin delivers the professional quality that commercial applications demand.

Manufacturer Resources

Corbin Russwin Condensed Catalog

Product Specs

Product Group:
Lock Parts and Accessories
Product Subgroup:
Parts and Accessories
Product Type:
Screw Pack
Commercial/Residential:
Commercial
Subcategory:
Parts and Accessories
For Use With:
ML2200 Series Mortise Lock (Old
Product Function:
Screw
Department:
Door Hardware

Corbin Russwin 421F25 – Frequently Asked Questions

1) What lock does the Corbin Russwin 421F25 machine screw fit?
The 421F25 is a genuine Corbin Russwin machine screw for the ML2200 Series mortise lock (old style). It is sized 8-3 x 5/16. If your lockbody is a current-production ML2200, confirm the part callout on your service parts breakdown before ordering, since the old and current cases use different fasteners.
2) Will replacing a screw on an ML2200 mortise lock affect its fire rating?
The ML2200 mortise lock is UL/cUL listed to UL10C positive pressure for 3-hour fire doors up to 4' x 10' single or 8' x 10' pair. Servicing it with the OEM 421F25 screw keeps the assembly as listed; substituting a hardware-store fastener in a fire door lock is what puts that listing in question.
3) I need to re-hand an old ML2200 mortise lock. Do I have to pull screws out of the case?
No. The ML2200 uses a quick reversible latchbolt, so handing is changed without disassembling the lock case. You would only be into the 421F25 machine screws if you are replacing missing or stripped fasteners during service, not for a re-hand.
4) What are the key dimensions of the ML2200 mortise lock these screws service?
The heavy-gauge steel lockcase measures 5-7/8 x 4 x 15/16 inches, with a 2-3/4 inch backset and a standard 1-3/4 inch door thickness. The latchbolt throws 3/4 inch, the auxiliary latch has a 9/16 inch effective throw, and the stainless deadbolt throws 1 inch into a 4-7/8 x 1-1/4 inch ANSI straight lip strike. Useful numbers to confirm you are working on an ML2200 case before ordering the 421F25.
5) Is this screw for a commercial mortise lock or residential hardware?
Commercial. The 421F25 serves the ML2200 Series mortise lock, which is an ANSI/BHMA A156.13 Series 1000 Operational and Security Grade 1 lock used in offices, schools, healthcare, retail and multi-tenant buildings.
How fast can I get the Corbin Russwin 421F25 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 421F25 come with a warranty?
Absolutely. The Corbin Russwin 421F25 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 421F25?
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 421F25 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.
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