Arrow 550H-44 MK Series Hotel ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$17.15
Image coming soon

Arrow 550H-44 MK Series Hotel Tailpiece Replacement Part for T & D Knobs

(No reviews yet) Write a Review

Model: 550H-44

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

$17.15
Adding to cart… The item has been added
Free Shipping on orders over $199
We price match and offer bulk discounts! Click Add to Quote. It's quick and easy.
✨
Earn points with this purchase! You can redeem points for giftcards, iPads, XBox's and more. View Rewards
Free Keying on all locks
You may also like

Arrow 550H-44 MK Series Hotel Tailpiece Replacement Part for T & D Knobs

The Arrow 550H-44 is a commercial-grade replacement tailpiece designed specifically for the MK Series Hotel lock line, engineered for compatibility with T and D knobs. As a genuine Arrow replacement part, this tailpiece ensures proper fit and function when servicing or restoring MK Series Hotel locksets in demanding commercial environments. Ideal for facility maintenance professionals and locksmiths requiring an exact OEM-matched cylinder component.

Key Features

  • Genuine Arrow Replacement Part: Factory-specified 550H-44 tailpiece ensures precise compatibility with MK Series Hotel locksets for reliable, long-term performance.
  • MK Series Hotel Compatibility: Engineered exclusively for Arrow MK Series Hotel knob locks, maintaining original operational integrity after service or repair.
  • T & D Knob Application: Designed for use with Arrow T and D style knobs, ensuring correct mechanical engagement with the cylinder and locking mechanism.
  • Commercial-Grade Construction: Built to Arrow's commercial standards, delivering the durability required for high-use hotel and hospitality environments.
  • Cylinder Component: Functions as a critical cylinder tailpiece, translating cylinder rotation to the locking bolt for proper lock operation.
  • Cost-Effective Restoration: Replacing a worn or damaged tailpiece with this genuine Arrow part extends the service life of existing MK Series hardware without full lockset replacement.

Technical Specifications

  • Department: Door Hardware
  • Product Category: Mechanical Locks
  • Product Group: Parts and Accessories
  • Subcategory: Parts and Accessories
  • Product Subgroup: Parts and Accessories
  • Product Type: Cylinders
  • Parts and Accessories Type: Replacement Parts
  • Commercial/Residential: Commercial
  • Product Model: 550H-44
  • Features: Arrow Parts

Typical Applications

  • Hotel and Hospitality Facility Maintenance
  • Commercial Office Building Lock Servicing
  • Multi-Tenant Residential Property Repairs
  • Educational Facility Hardware Restoration
  • Healthcare Institution Door Hardware Maintenance
  • Institutional and Government Building Upkeep
  • Locksmith and Door Hardware Service Professionals

Why Arrow 550H-44?

Arrow has long been recognized for producing commercial-grade door hardware components that meet the rigorous demands of institutional and hospitality environments. The 550H-44 tailpiece is engineered to Arrow's exact specifications, ensuring seamless integration with MK Series Hotel locksets and preserving the performance characteristics of the original installation. For facilities managers and service professionals, sourcing a genuine Arrow replacement part eliminates guesswork and ensures dependable lock operation after every repair.

Manufacturer Resources

Arrow Express Catalog

Product Specs

Department:
Door Hardware
Product Category:
Mechanical Locks
Product Group:
Parts and Accessories
Subcategory:
Parts and Accessories
Product Subgroup:
Parts and Accessories
Product Type:
Cylinders
Parts and Accessories Type:
Replacement Parts
Commercial/Residential:
Commercial
Product Model:
550H-44
Features:
Arrow Parts

Arrow 550H-44 – Frequently Asked Questions

1) What exactly is the Arrow 550H-44 part, and what does it do in the lock?
The 550H-44 is a tailpiece, the flat metal blade that carries cylinder rotation through to the locking mechanism. It is not a cylinder or a complete lockset, so if the cylinder itself is worn or you need a rekey, the tailpiece alone will not fix it. Arrow specifies it for the MK Series Hotel lock line.
2) Will the Arrow 550H-44 tailpiece work with any Arrow knob?
No. It is specified for Arrow T and D style knobs on MK Series Hotel locks. Other Arrow knob styles engage differently, so pulling a 550H-44 into a non-T/D knob is the wrong part.
3) The cylinder itself is worn, not just the tailpiece - what should I order instead of the Arrow 550H-44?
The 550H-44 is only the tailpiece, the part that translates cylinder rotation to the locking bolt, so it does not help if the plug or pin stack is the problem. For a key-in-knob cylinder replacement, the Kaba Ilco 1599 is a key-in-knob replacement cylinder and the Kaba Ilco 1539 is a key-in-knob/lever universal cylinder; the Kaba Ilco 1579 is a knob and lever cylinder made for Sargent locks. Medeco's 1065140 is a 5-pin retrofit cylinder listed for the Arrow JL interconnected lock if the opening is that Arrow line rather than MK Hotel.
4) Is there a substitute tailpiece for the Arrow 550H-44 from another brand?
No. The Arrow 550H-44 is a genuine Arrow replacement tailpiece engineered specifically for MK Series Hotel knob locks with T and D knobs, so the mechanical engagement between cylinder and locking mechanism is particular to that lockset. The alternatives that carry their own tailpieces are complete cylinders, not loose tailpieces - for example the Medeco 1065244 is a 5-pin rim lazy motion cylinder supplied with an Emtek tailpiece, and the Corbin Russwin 3070 is a 6-pin rim cylinder housing with a 1-7/8 inch tailpiece. Those replace the cylinder, not a worn tailpiece inside an Arrow MK hotel knob.
5) Our opening is an aluminum storefront with a deadlock, not a hotel knob lock - what takes the place of the Arrow 550H-44 there?
Nothing from the MK Hotel parts line applies; the 550H-44 serves Arrow MK Series Hotel knob locks. On a storefront deadlock the keyed component is a cylinder pull or mortise cylinder: the Adams Rite 4024 is a cylinder pull with trim plate mounting for the MS1847 deadlock/deadlatch, the 4025 is a five pin tumbler cylinder pull with through-screws for the same MS1847, and the Adams Rite 4036 is a Grade 1 mortise cylinder in the 4036 Series with a 1/2 inch minimum door thickness. For a wood door deadlock, the Adams Rite 4026 is listed for the 5017 wood door deadlock/deadlatch.
6) Can I repair a worn MK Series hotel lock without replacing the whole lockset?
That is the point of the 550H-44. If the failure is a worn or twisted tailpiece (key turns but the bolt does not follow), swapping in the factory 550H-44 restores operation and leaves the existing knob, cylinder and chassis in place.
7) Is there an aftermarket equivalent to the Arrow 550H-44 tailpiece?
Order the Arrow part. Tailpiece length and blade geometry are specific to the MK Series Hotel chassis, and the cross-brand cylinders we carry (Schlage 20-021 and 20-022 rim cylinders, for instance, which differ only in vertical versus horizontal tailpiece cam) are complete cylinders with their own tailpieces, not drop-in blades for an Arrow MK knob lock.
8) We are standardizing keying across a hotel - is the Arrow 550H-44 part of that decision, or do we need interchangeable core cylinders?
The 550H-44 is a tailpiece for Arrow MK Series Hotel knob locks and carries no keyway or pinning, so it plays no part in a keying program. For a facility moving to interchangeable core so cores can be rotated without pulling hardware, the BEST 1CB is a 150 Series interchangeable core cylinder, the BEST 1CDF is a drill-resistant patented interchangeable core 7-pin brass 150 Series core, and the Schlage 20-057 is a 6-pin full-size interchangeable core rim cylinder with a convertible tailpiece cam. Those are lock or cylinder-level changes; the 550H-44 restores existing MK hotel hardware in place.
9) What is the difference between the Arrow 550H-44 and a mortise cylinder like the Corbin Russwin 1000?
They sit at different levels of the lock. The Arrow 550H-44 is a replacement tailpiece for MK Series Hotel knob locks using T and D knobs. The Corbin Russwin 1000 is a Grade 1 mortise cylinder in a 1-1/2 inch length with an A02 straight cam, and the Corbin Russwin 1070 is a 1-1/4 inch 6-pin mortise housing with an A01 cloverleaf cam - those thread into a mortise lock body and are specified by length and cam shape, not by knob style. If the door has a mortise lock rather than an Arrow MK hotel knob lock, a cylinder from that family is the correct part.
10) Would a rim cylinder tailpiece work in place of the Arrow 550H-44?
No - rim tailpieces look similar but are cut and oriented for exit device and rim lock hardware, not for an Arrow MK Series Hotel knob. Schlage's 20-021 rim cylinder uses a vertical tailpiece cam and the 20-022 uses a horizontal tailpiece cam, and those orientations are matched to the device behind the door. The 550H-44 is dimensioned to engage Arrow T and D knobs and the MK hotel locking mechanism, so it is the part to use on that lockset.
11) Is the Arrow 550H-44 the right part if I only need to rekey the lock?
No. The 550H-44 is a replacement tailpiece for Arrow MK Series Hotel knob locks; it holds no pins and changes nothing about the key. Rekeying is done at the plug or core - the BEST 1C5 is a standard 5-pin cylinder core, and the Schlage 20-057-C is a full size interchangeable core in the C keyway with a 643E aged bronze finish. Order the 550H-44 when the tailpiece itself is worn or damaged and the lockset is otherwise sound.
12) The door has a keyed deadbolt above the knob - does the Arrow 550H-44 fit that cylinder?
No. The 550H-44 is matched to Arrow MK Series Hotel knob locks with T and D knobs, not to deadbolt cylinders. For a deadbolt, the Kaba Ilco 1549 is a key-in-deadbolt cylinder, the Medeco 1012040 is a 6-pin lazy motion rim cylinder for Kwikset single cylinder deadbolts, and the Medeco 1075127 is a 5-pin rim type lazy motion single cylinder for handlesets and deadbolts. Match the part to the lock body it serves.
13) Our lever trim is Falcon, not Arrow - can I still use the 550H-44?
No. The Arrow 550H-44 is built for Arrow MK Series Hotel knob locks using T and D knobs, so it will not engage another maker's lever trim. For Falcon key-in-lever hardware, the Falcon A23161-05 G is a key-in-lever cylinder in the RU/T Series with a 6-pin G keyway, keyed different and supplied with two cut keys. For Detex hardware taking a mortise cylinder, the MC65 is a 1-1/8 inch 6-pin mortise cylinder in the Schlage C keyway.
14) Is the 550H-44 rated for hotel and other high-traffic commercial doors?
It is a commercial part, built to Arrow's commercial standards for hotel and hospitality use. Property managers standardizing guestroom hardware across a property can stock it as the service item for MK Series Hotel knob locks rather than carrying spare complete locksets.
15) How is the Arrow 550H-44 sold, and is there more than one version?
One configuration only, model 550H-44. There is no finish, length, or handing choice to specify, so the model number is the whole order.
16) We need a non-keyed knob on one guest room door - does the Arrow 550H-44 cover that?
The 550H-44 is a functional tailpiece that carries cylinder rotation to the locking bolt, so it belongs on a keyed MK Series Hotel lock being serviced. For an opening that needs the look of a keyed cylinder without any key function, the BEST 12E Series dummy rim cylinder with a 1-5/32 inch diameter fills the hole without operating anything. Choose by whether the door must actually lock.
How fast can I get the Arrow 550H-44 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 Arrow 550H-44 come with a warranty?
Absolutely. The Arrow 550H-44 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 Arrow 550H-44?
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 Arrow 550H-44 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.
!