The Falcon 600278 is the OEM trim cylinder nut for Falcon 24 and 25 Series exit device outside trim, specifically called out as Item "g" in the Falcon 19/24/25/XX Series Exit Devices Service Manual for the 510L, 510L-BE, 511L, 513K, and 513K-BE trim configurations. The cylinder nut is the threaded retention nut that secures the outside cylinder in the trim escutcheon from behind - it threads onto the tail of the cylinder and clamps against the inside face of the escutcheon to prevent the cylinder from being rotated, extracted, or removed from the outside.

This part is in stock and currently listed under SKU 600278 on this page. Note: the URL on this page references "090041-hook-spring-pkg," which is a different 25 Series trim component (the hook spring package, Item "f" on the same service manual diagram). The correct part for this page is the cylinder nut, 600278.

Falcon 25 Series Trim Cylinder Nut: Why This Part Fails

The cylinder nut on any exit device trim is one of the highest-stress fasteners in the assembly. On keyed outside trim - classroom (510), vandal resistant (511), or knob (513) functions - the cylinder nut transmits the rotational resistance whenever someone attempts to torque the cylinder without the correct key. Repeated forced key entry attempts, lock picking attempts, or direct cylinder attack all create rotational load on the nut. Over time, particularly in aluminum trim escutcheons, the cylinder nut can strip, crack, or back off its thread engagement, leaving the cylinder loose in the escutcheon.

A loose cylinder nut is a security failure. When the nut backs off sufficiently, the cylinder can rotate freely in the escutcheon without key operation - the cylinder loses its anti-rotation retention and can be gripped and extracted from outside. The 600278 cylinder nut replacement restores positive cylinder retention without disassembling the trim from the device or the device from the door.

Falcon Exit Device Catalog: 24 and 25 Series Trim Compatibility

The 600278 cylinder nut is compatible across the full 24 and 25 Series Falcon exit device family in the keyed trim configurations. The 25 Series covers rim (25 Rim), surface vertical rod (25-V), concealed vertical rod (25-C), wide clearance CVR (25-C-WDC), and mortise (F25-M) device types. The 24 Series covers rim (24 Rim), surface vertical rod (F24-V), and concealed vertical rod (F24-C) devices.

All of these device types accept the same 510/511/512/513/717 trim family on the outside, and the 600278 cylinder nut secures the outside cylinder in the trim escutcheon in all keyed configurations across this device family.

Falcon Cylinder Parts: 25 Series Trim Assembly Breakdown

The Falcon 19/24/25 Series service manual lists seven distinct field replacement parts for the 25 Series outside trim:

Item a (600272) = Backplate Assembly. Item b (600273) = 510/512/513 Slider Assembly, or 600282 for VR slider. Item c (600274) = L (Lever) Springs package of 2, or 600284 for K/T springs. Item d (600275) = Locking Hook Package. Item e (600276) = L/K Spindle Cam Package with spindle cam retaining ring. Item f (090041) = Hook Spring Package. Item g (600278) = Trim Cylinder Nut - this product.

Each of these seven items is a separately orderable field replacement part. The cylinder nut (600278) is Item g - the last component in the trim diagram. It is also the component most frequently needed as a standalone replacement when the cylinder itself has been serviced (rekeyed or swapped) and the existing nut was lost, stripped, or damaged during cylinder removal.