Security Parts stocks Schlage tubular lock parts including the THP-8201 and THP-8301 passage spring latch assemblies, the THP-8219 and THP-8319 privacy latch assemblies, and the B and C design privacy roses. The THP part number encodes the backset: 82xx = 2-3/8 inch backset for 1-3/8 inch doors, 83xx = 2-3/4 inch backset for doors over 1-3/4 inch. Fire-rated versions carry the F suffix. Always confirm door thickness before ordering any THP latch assembly. The LT Series was discontinued in October 2025 and replaced by the PT Series, but THP latch and rose parts remain available for existing LT Series installations.

Tubular locks are on more interior doors in commercial buildings than any other lock type. Restrooms, private offices, utility closets, conference rooms, storage alcoves. They do not require keyed access in most of these applications. They do require reliable passage or privacy function, a latch that retracts cleanly under normal lever force, and on privacy doors, a restoring feature that prevents accidental lockouts after hours.

When a Schlage tubular lock latch fails or a privacy rose needs replacement, the THP part number system tells you exactly which component applies to which door thickness. Most wrong-part orders on tubular lock service calls come from a single error: ordering the 2-3/4 inch backset latch for a door that takes the 2-3/8 inch backset, or the reverse. This guide covers every part in the Schlage tubular lock catalog at SecurityParts.com, the functions, the fire-rated options, and the diagnostic steps that identify the correct part before you order. Browse the complete tubular lock parts catalog at SecurityParts.com.

What a Tubular Lock Is and Where It Belongs

A tubular lock uses a single bore through the door face for the entire lock chassis, with the latch assembly passing through a separate edge bore. The lock body threads directly through the door face bore. Both the inside and outside trim attach to the latch body rather than to a separate chassis housing.

This construction is lighter and less expensive than a cylindrical lock. The tradeoff is that tubular locks support fewer functions, accept fewer cylinder options, and do not achieve the same security ratings as cylindrical locks on keyed applications. In practice this is not a limitation for most tubular lock applications because the doors they serve do not require keyed locking at all.

The typical tubular lock application in a commercial building is a non-keyed interior door: a restroom, a private office where the occupant controls access by the inside privacy button, a conference room passage function, or a utility closet where entry control is not required. For any door that requires a keyed entrance function, a storeroom function, or a classroom lockdown function, browse the cylindrical lock parts catalog for the Schlage ND Series, ALX Series, or Falcon T Series instead.

Tubular Lock vs Cylindrical Lock: Choosing the Right Hardware

LT Series Functions: What Was Available

The Schlage LT Series offered four functions. Understanding which function is installed is the first requirement before ordering any replacement latch or trim component.

The THP Part Number System: How to Read It

Every Schlage LT Series latch assembly has a THP part number that encodes the function type and backset in its digits. Understanding this system eliminates the most common wrong-part order on tubular lock service calls.

Every Replaceable Component in the Schlage LT Series

Spring Latch Assembly (THP-8201 and THP-8301)

The spring latch is the beveled bolt that automatically extends when the door closes and retracts when the inside or outside lever is turned. On the LT Series passage function, both inside and outside levers always retract the latch freely with no locking mechanism involved.

Spring latch failure presents as a latch that does not retract when the lever is turned, a latch that does not spring back to the extended position after retraction, or a latch that binds in the faceplate and requires excessive lever force to retract. A latch that binds in the faceplate is often a door alignment problem rather than a latch failure: the door has settled and the latch tip is contacting the strike plate edge rather than the bolt pocket. Check strike alignment before replacing a latch that binds on closing.

Each THP spring latch assembly includes the latch body, faceplate, and mounting screws in the package. No additional hardware is required for a direct replacement on a door with matching backset.

Privacy Latch Assembly (THP-8219 and THP-8319)

The privacy latch assembly is more complex than the spring latch. In addition to the spring latch body, it includes the internal locking pin mechanism that engages when the push button on the inside rose is pressed, locking the outside lever. It also includes the restoring mechanism that releases the outside lever when the door closes.

Privacy latch failure presents as a latch that does not lock the outside lever when the push button is pressed, a push button that sticks in the locked or unlocked position, or a latch that does not restore to unlocked on door closing. The restoring mechanism is a cam component inside the latch body that detects door closing through the latch tip contact with the strike. If the door has a strike plate that is positioned so the latch tip does not fully contact the strike face on closing, the restoring function may not activate reliably. Verify strike plate position before diagnosing internal restoring mechanism failure.

Privacy Rose: B Design (Part 09-486) and C Design (Part 09-459)

The privacy rose is the cover plate on the inside face of the LT40 privacy door that contains the push button for locking the outside lever and the emergency access hole for unlocking from outside with a pin or coin. SecurityParts.com stocks two privacy rose designs for the LT Series:

Part 09-459 (C design privacy rose): The C design rose uses a rounder, more contemporary profile. Available in multiple finishes to match existing LT Series hardware.

Part 09-486 (B design privacy rose): The B design rose uses a slightly different profile. Finish-specific ordering required.

Privacy roses are finish-specific. Always confirm the finish code before ordering a replacement rose. The most common finish codes for LT Series hardware are 626 (satin chrome), 619 (satin nickel), 622 (matte black), and 625 (bright chrome). Installing a rose in the wrong finish leaves a visible mismatch on the interior door face that requires a second return and reorder.

Strike Plate

The LT Series uses a T-strike (T-shaped strike plate) as the default, not the ANSI curved lip strike used on cylindrical locks and deadbolts. The T-strike covers the latchbolt pocket in the door frame with a lip configuration that guides the spring latch tip into the pocket on every door close.

Strike options for the LT Series include the T-strike square corner (10-001 series, specify lip length from 1 inch to 2 inches), T-strike round corner (10-004, 1/4 inch radius, 1-1/8 inch lip length), and ANSI strike (10-025 series, 1-1/4 inch by 4-7/8 inch, specify lip length). The T-strike is typically used when the door frame has a standard tubular lock prep. The ANSI strike is used when the door frame prep matches the ANSI standard for cylindrical locks and the installer wants to use the same frame prep for both the tubular lock and any adjacent hardware.

Levers and Solid Brass Construction

The LT Series levers are manufactured from solid brass or solid stainless steel, not pressure cast zinc. This is the construction distinction that separates the LT Series from most competitor tubular locks and from the Schlage S Series and other economy tubular lines. Solid brass levers have a heavier feel, longer wear life, and a more premium finish durability than cast zinc levers.

The LT Series levers move both up and down for a bidirectional operational experience that matches the Schlage L Series mortise lock levers and Von Duprin exit devices. Inside and outside levers operate independently, allowing the inside lever to spring back without affecting the outside lever position. This independent operation creates a quieter, less institutional operational character compared to coupled-lever designs where both levers move together.

Fire-Rated Tubular Locks: When Are They Required

Fire-rated tubular locks are required when the door is part of a UL-listed fire-rated assembly. In commercial buildings, the most common application for fire-rated tubular locks is on restroom doors, private office doors, and utility closet doors in corridors or exit passageways that have a fire separation requirement.

Interior partition walls between office tenant spaces and building corridors often require a fire resistance rating. The doors in these walls must use hardware that is listed for the fire rating of the wall assembly. A 20-minute fire-rated door assembly is the most common rating level in interior partition applications. The Schlage LT Series with THP-F fire-rated latch achieves this 20-minute UL rating.

Schlage PT Series: The Current Replacement for LT Series

The Schlage PT Series became the replacement for the discontinued LT Series after October 2025. For facility managers maintaining mixed-generation buildings, understanding the differences matters for ongoing parts planning.

PT Series vs LT Series: Key Differences

The PT Series is purpose-built for four functions (passage, privacy, passage fire-rated, privacy fire-rated) with 10 lever styles and 6 finishes. The LT Series offered 31 lever designs and 14 finishes, which is why the LT Series was specified on premium projects requiring extensive design flexibility. The PT Series reduces the choice set in exchange for a more cost-competitive price point.

The PT Series uses a stainless steel latchbolt with a 1/2 inch throw. The snap-on wrought brass rose eliminates exposed rose screws for a cleaner finished appearance on the door face. The PT Series suites with the PM Series mortise locks using shared levers and rose designs, following the same suiting strategy as the LT and L Series relationship.

For new installations on premium projects requiring extensive lever design selection and L Series suiting, the LT Series parts available at SecurityParts.com support existing installations. For new installations where the PT Series sufficient design selection meets the specification, the PT Series is the current Schlage offering.

Parts Availability for Existing LT Series Installations

SecurityParts.com stocks THP latch assemblies and privacy roses for existing LT Series installations. A building specified with LT Series hardware in 2018 or 2022 will need THP latches and privacy roses for the next 15 to 20 years of normal service. The discontinuation of the LT Series as a new product does not affect the availability of replacement parts for installed units. Browse the tubular lock parts catalog for current stocking status on all THP assemblies.

How to Identify the Correct THP Part Before Ordering

Two measurements and one visual check are all that is needed before any THP parts order.

1. Measure the backset. The backset is the distance from the center of the door bore to the edge of the door face. On a standard commercial hollow metal or solid core wood door, measure from the center of the door handle hole to the door edge. If this dimension is approximately 2-3/8 inches, order THP-82xx. If approximately 2-3/4 inches, order THP-83xx. Do not guess. A THP latch with the wrong backset will not reach the strike properly and the door will not latch correctly.

2. Identify the function (passage or privacy). Does the current installation have a push button on the inside rose? If yes, it is a privacy function. Order THP-8219 or THP-8319. If the inside and outside levers both always retract the latch freely with no button, it is a passage function. Order THP-8201 or THP-8301.

3. Check the door for a fire label. Look at the top or hinge edge of the door for a UL fire label. If present, order the F-suffix version of the correct THP latch. If no label is visible, the standard non-F version is appropriate.

Browse the Schlage tubular lock parts catalog at SecurityParts.com with part numbers and diagrams for every THP assembly. For the complete Schlage hardware range including LT Series tubular locks, ND Series cylindrical locks, L Series mortise locks, and CS210 interconnected locks, browse the Schlage commercial hardware catalog. Pre-order support is available at 845-935-0301 or through the contact page.

What Fails First on Schlage Tubular Locks

1. Spring latch assembly. Latch spring fatigue is the primary failure mode on high-cycle doors. The latch bolt does not return to the extended position after retraction, which means the door does not latch on closing. A door that requires a push to close and latch is always a spring latch issue. Replace the full THP assembly, not just the spring.

2. Privacy push button mechanism. On LT40 privacy doors, the push button or the internal locking pin can wear or bind after years of use. The symptom is a push button that requires excessive force to depress, does not stay in the locked position, or pops out immediately without locking the outside lever. The privacy latch assembly (THP-8219 or THP-8319) replaces the complete mechanism.

3. Restoring mechanism failure. The restoring feature that unlocks the outside lever on door closing can fail to actuate if the latch tip does not fully contact the strike plate on closing (strike misalignment) or if the internal restoring cam wears. Always check strike alignment before assuming the restoring cam has failed. Adjusting the strike position often restores this function without any parts replacement.

4. Rose assembly. The inside privacy rose sustains the most cosmetic wear of any component because it receives direct hand contact on every entry and exit. Finish wear and physical cracking from abuse require rose replacement. Always confirm the design (B or C) and finish code before ordering.

5. Lever assembly. The solid brass levers on the LT Series are more durable than cast zinc alternatives, but they can still bend or crack under deliberate physical abuse. Lever replacement requires confirming the specific lever design from the 31 LT Series options and the finish code.

Related Parts and Products at SecurityParts.com

Tubular locks are typically part of a complete interior door hardware package. The same building that uses LT or PT Series tubular locks on restroom and corridor doors also uses cylindrical locks on offices, mortise locks on entries, and door closers on fire-rated corridor doors.

For Schlage ND Series, ALX Series, and Falcon T Series cylindrical lock parts on keyed office doors and storerooms in the same facility, browse the cylindrical locks catalog. For Schlage L Series and Falcon MA Series mortise lock parts on main entry doors and secured offices, browse the mortise locks catalog. For Schlage CS210 interconnected lock parts on dwelling unit entry doors requiring single-motion egress, browse the interconnected locks catalog. For Schlage B Series deadbolt parts on secondary doors, browse the deadbolts catalog. For LCN door closer parts on fire-rated corridor doors in the same building, browse the door closers catalog. For Von Duprin and Falcon exit device parts on building egress doors, browse the commercial exit devices catalog.

Browse the complete all products and parts catalog to source Schlage, Von Duprin, LCN, Falcon, and Detex hardware in a single session.