A3700 Series

The American Lock A3700 Series is the 2-inch wide solid brass door-key-compatible padlock line from American Lock, now under Master Lock Company. These padlocks are specified on commercial and institutional facilities where padlocks need to operate on the same key as the building's door hardware, eliminating the need for a separate padlock key on every key ring. Every lock in the A3700 Series is available with or without a cylinder, accepting SFIC (Small Format Interchangeable Core) in 16 keyway options, or a conventional key-in-knob cylinder in up to 27 keyway configurations.

If you're searching for "american lock sets," "american lockset," "american lock set," or the "3700 capital series lock," this category covers the A3700 and A3701 padlocks at American Locksets, a commercial hardware distributor trusted since 2001.

What Is the American Lock A3700 Series?

The A3700 Series is American Lock's 2-inch wide solid brass body padlock with a hardened boron alloy shackle and a dual ball bearing locking mechanism. The 2-inch body width places this series one step up from the 1-3/4-inch A3600 Series, providing a larger body mass and a 3/8-inch (10mm) shackle diameter with greater cut resistance than the 5/16-inch shackle on the A3600. The solid brass construction is not plated over steel: it's corrosion-resistant brass through the body, which matters on outdoor applications, coastal environments, and any installation where painted steel would degrade quickly.

A3700 vs A3701: Shackle Length Is the Only Difference

The two standard models in this series differ only in shackle height. The A3700 has a 1-1/8-inch tall shackle. The A3701 has a 2-inch tall shackle. Both models use the same 3/8-inch diameter boron alloy shackle, the same 2-inch wide solid brass body, the same dual ball bearing locking mechanism, and the same cylinder compatibility. The correct model for a given application depends entirely on how much shackle clearance the installation requires.

Short shackle (A3700) is used when the hasp, loop, or mounting point sits close to the padlock body and a long shackle would leave exposure that could be exploited with bolt cutters. Long shackle (A3701) is used when the hasp or chain requires the shackle to reach farther, such as on certain gate hardware, locker applications, or chained equipment.

Door-Key Compatible: What This Means in Practice

"Door-key compatible" is the defining characteristic of the A3700 Series and the primary reason it's specified over generic padlocks on commercial projects. It means the padlock body is designed to accept the same cylinder format as the building's door hardware, so a facilities manager or security team can carry one key that opens both the building doors and the padlocks on gates, equipment enclosures, storage cages, and utility areas.

The WO suffix on the model number (A3700WO, A3701WO) stands for "Without [core]." The padlock ships without any cylinder or core installed, and the buyer specifies which cylinder or core type they need based on the facility's existing key system. This approach is used on master key projects where the cylinder must be combinated to an existing system before installation.

SFIC and Conventional Cylinder Options

Small Format Interchangeable Core (SFIC)

The A3700 Series accepts SFIC cores from BEST, Arrow, and Falcon, giving the facility manager the ability to pull and replace the core using a control key without disassembling the padlock body. This is the correct configuration for large facilities with institutional masterkey systems where rekeying a padlock should be as fast as rekeying a door. Sixteen SFIC keyway options are available.

Conventional Key-In-Knob Cylinders

For facilities running a conventional masterkey system rather than an IC system, the A3700 accepts key-in-knob style cylinders in up to 27 keyway configurations. This covers Schlage C, Kwikset, BEST, Arrow, Corbin, Russwin, Sargent, and most other major commercial keyways. The cylinder ships with the correct driver for the A3700 body when ordered as part of a padlock package.

Keying Options

The A3700 Series is available in four keying configurations. Keyed Different (KD) means each padlock in an order operates on a unique key. Keyed Alike (KA) means all padlocks in an order operate on the same key. Master Keyed (MK) means the padlock operates on its individual change key and also on a separate master key. Keyed Alike Master Keyed (KAMK) provides keyed alike padlocks within a grand master system. Uncombinated (UN) ships the cylinder or core without any bitting, for facilities that will combinate the cylinder themselves.

Non-Key-Retaining vs Key-Retaining Function

Standard function on the A3700 Series is Non-Key-Retaining (NKR), meaning the key can be removed from the cylinder in both the locked and unlocked positions. The NRK (Non-Removable Key or key-retaining) option is available and requires the key to remain in the cylinder when the shackle is open, ensuring the key is never left in a locked padlock and reducing the risk of leaving the location unsecured.

Applications for the A3700 Series Padlock

Commercial facilities use the A3700 on service entrance gates, rooftop HVAC access panels, storage cage doors, electrical room hasps, and fleet vehicle chain locks. Institutional facilities including schools, hospitals, and government buildings specify A3700 padlocks because the door-key compatibility eliminates padlock-specific keys from the facilities key ring and allows the master key system to cover padlocked areas alongside door hardware.

Browse the complete A3700 Series padlock catalog at American Locksets. For related American Lock padlock series, see the full range of commercial locks and cylinders and cores available from American Locksets.

Why American Locksets for American Lock A3700 Series Padlocks

Ordering the A3700 correctly requires knowing the cylinder format your facility uses, the correct keying configuration for the project, and whether the WO (without core) version or a pre-built complete assembly is the right approach. At American Locksets, we've shipped American Lock products to commercial contractors, facilities teams, and security integrators since 2001. We stock the A3700WO and A3701WO in both SFIC and conventional cylinder configurations. Free shipping on orders over $300. 

Frequently Asked Questions About the American Lock A3700 Series

Q: What is the American Lock A3700 Series?

A 2-inch wide solid brass door-key-compatible padlock with a hardened boron alloy shackle and dual ball bearing locking mechanism. Accepts SFIC or conventional key-in-knob cylinders to match existing door hardware key systems.

Q: What is the difference between the A3700 and A3701?

Shackle height only:

• A3700: 1-1/8-inch tall shackle

• A3701: 2-inch tall shackle

Both share the same body, shackle diameter, and cylinder compatibility.

Q: What does WO mean on the A3700WO model number?

WO stands for Without [core or cylinder]. The padlock ships without any cylinder installed, allowing the buyer to specify and install the correct cylinder or SFIC core for their existing key system.

Q: What keyways are compatible with the A3700 Series?

Up to 27 conventional keyways including Schlage C, Kwikset, BEST, Sargent, Corbin, and others. SFIC accepts 16 keyway options from BEST, Arrow, and Falcon.

Q: What keying options are available on the A3700 Series?

Four options: Keyed Different (KD), Keyed Alike (KA), Master Keyed (MK), and Keyed Alike Master Keyed (KAMK). Uncombinated (UN) is also available for facilities that key cylinders in-house.

Q: Can the A3700 Series be masterkeyed with door locks?

Yes. Because it accepts the same cylinder formats as commercial door hardware, the A3700 can be incorporated into the same masterkey system as the building's cylindrical or mortise door locks.