The Schlage S00031733793-KIT is the OEM ND Series ND66 chassis kit, unassembled, documented in the Schlage ND Series Service Manual. The kit ships with no finished parts - raw internal chassis components only, requiring field assembly by a qualified installer before installation. This is the Trim Assembly chassis for the ND66 Store lock function.

The ND66 is a specialized function in the Schlage ND Series catalog. It carries ANSI Function F91 - double cylinder - which makes it distinct from every other common storeroom or entrance function in the ND lineup. Ordering and installing this chassis on the wrong opening is a serious code compliance issue. Confirm the ND66 is the correct function specification before purchasing.

What the ND66 Store Lock Does

The ND66 is ANSI Function F91, the double cylinder store lock. The functional behavior: a key inserted in either the inside lever or the outside lever simultaneously locks or unlocks both levers. Both sides of the door are controlled at the same time with one key operation.

This is very different from the ND80 storeroom function, where the outside lever is always locked and the inside lever is always free. On the ND66, the inside lever is NOT always free - it is locked when a key has placed the device in the locked state. Egress from inside requires a key, which is the defining characteristic of a double cylinder function.

Allegion's official ND66 product page includes an explicit caution: "Double cylinder locks on any door, in any structure, which is used for egress can create a life safety hazard in times of emergency and their use is not recommended. Installation should be in accordance with existing codes only." The ND66 is a specialized function for specific controlled applications - retail environments, secured storage in institutional settings, and other occupancies where local code specifically permits double cylinder functions on egress doors. Verify AHJ approval and compliance with applicable fire, building, and life safety codes before installation.

Schlage Chassis Kit: ND66 vs ND80 vs ND50

The S00031733793-KIT is specifically the ND66 double cylinder chassis. This chassis is NOT interchangeable with the ND80 storeroom chassis (single cylinder, inside lever always free) or the ND50/53 entrance/office chassis (inside push button mechanism). Each function uses a different chassis architecture because the internal mechanism behavior is different.

The ND66 double cylinder chassis is internally more complex than standard single-cylinder function chassis, which is why the kit price is significantly higher than the ND50/53 kit. The internal cam linkage that connects inside and outside cylinder operations - so that one key rotation on either side affects both levers simultaneously - is the additional mechanism component that differentiates this chassis.

Schlage ND Series Performance: Platform Specs for the ND66 Chassis

The ND66 runs on the same ND Series mechanical platform that covers all ND Series functions. The platform specs confirmed from Allegion's official ND Series product page:

ANSI/BHMA A156.2 Grade 1 certified. Tested to 3 million cycles - three times the ANSI requirement. Abusive lever torque resistance: 3,100 inch-pounds without gaining access, more than 2.5 times the Grade 1 standard. Offset lever pull resistance: 1,600 foot-pounds against pry bar attack. Virtually zero droop or wobble after 16 million cycles. UL listed for 3-hour A label fire door on single doors up to 4' x 10' and pairs up to 8' x 8'. Standard door thickness 1-5/8" to 2-1/8". ANSI 161 door prep - universal across all ND Series functions, meaning the ND66 installs in any standard ND Series door preparation without modification.

For the complete Schlage ND Series chassis kit catalog, SecurityParts stocks OEM cylindrical lock components.