Arrow 550AM-44 Tailpiece Repla...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$17.15
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Arrow 550AM-44 Tailpiece Replacement Part for MK Series T & D Knobs

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Model: 550AM-44

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

$17.15
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Arrow 550AM-44 Tailpiece Replacement Part for MK Series T & D Knobs

The Arrow 550AM-44 is a genuine OEM replacement tailpiece engineered specifically for Arrow MK Series T and D Knobs, excluding the Hotel Function configuration. Designed as a commercial-grade cylinder component, this tailpiece ensures proper cylinder-to-knob engagement and reliable mechanical lock operation when existing parts wear or require replacement. Sourced directly from Arrow's parts and accessories line, the 550AM-44 delivers a precise factory fit for compatible MK Series locksets.

Key Features

  • Genuine Arrow Replacement Part: OEM-quality tailpiece engineered to Arrow factory specifications for reliable, precise fit and function.
  • MK Series Compatibility: Designed specifically for Arrow MK Series T and D Knob configurations, ensuring proper cylinder-to-knob mechanical engagement.
  • Hotel Function Exclusion: Intended for standard T and D knob functions, not compatible with Hotel Function variants; verify function type before ordering.
  • Commercial-Grade Construction: Rated for commercial applications where consistent, dependable lock cylinder performance is required.
  • Cylinder Component: Classified as a cylinder replacement part, restoring proper tailpiece-to-cylinder interaction for smooth knob operation.
  • Easy Integration: Direct drop-in replacement for worn or damaged tailpieces within the compatible MK Series lockset family.

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: 550AM-44
  • Features: Arrow Parts

Typical Applications

  • Commercial Office Buildings
  • Educational Facilities
  • Healthcare Institutions
  • Retail Establishments
  • Multi-Tenant Residential Properties
  • Government and Municipal Buildings
  • Industrial and Warehouse Facilities

Why Arrow 550AM-44?

Arrow parts and accessories are manufactured to OEM standards, ensuring that replacement components like the 550AM-44 tailpiece maintain the mechanical integrity and performance characteristics of the original MK Series lockset. For commercial environments where lock reliability is non-negotiable, using genuine Arrow replacement parts is the professional choice to preserve proper function and extend hardware service life.

Manufacturer Resources

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:
550AM-44
Features:
Arrow Parts

Arrow 550AM-44 – Frequently Asked Questions

1) I have Arrow MK Series knobs on a hotel-function guest room door. Can I use the 550AM-44?
No. The 550AM-44 is built for standard MK Series T and D knob functions only, and the Hotel Function is specifically excluded. Ordering it for a hotel-function lockset gets you a part that will not engage correctly. Check the function stamped on the lock or the original order before you buy.
2) My Arrow knob turns with the key but the latch doesn't retract. Is a tailpiece the fix?
That is the classic failure a tailpiece replacement addresses. When the key turns freely but nothing happens at the latch, the tailpiece is usually twisted, sheared, or backed out of engagement. On an Arrow MK Series T or D knob, the 550AM-44 is the factory part that restores that cylinder-to-knob engagement. If the key won't turn at all, the problem is in the cylinder, not the tailpiece.
3) Can I use the Arrow 550AM-44 tailpiece on a rim exit device cylinder?
No. The 550AM-44 is built for Arrow MK Series T and D knobs and engages the knob's cylinder, not a rim device. Rim applications use a cylinder that comes with its own tailpiece cam - for example the Schlage 20-021 rim cylinder with a vertical tailpiece cam or the Schlage 20-022 with a horizontal tailpiece cam, where the cam orientation is matched to the device. Order the rim cylinder for that opening rather than a knob tailpiece.
4) If the whole cylinder in an Arrow MK Series knob is worn out and not just the tailpiece, what should I order instead?
The Arrow 550AM-44 is only the tailpiece, the part that transmits cylinder rotation into the knob mechanism on MK Series T and D knobs other than the Hotel Function. If the plug and pins are the problem rather than the tailpiece, a replacement key-in-knob cylinder is the part to buy. The Kaba Ilco 1599 is a key-in-knob replacement cylinder, and the Kaba Ilco 1539 is a key-in-knob and lever universal cylinder. Those replace the cylinder body itself, while the 550AM-44 replaces only the drive piece behind it.
5) Will the Arrow 550AM-44 work in an MK Series hotel function knob?
No. The 550AM-44 covers MK Series T and D knobs with the Hotel Function specifically excluded, so verify the function type stamped on the lockset before ordering. If the opening needs a different platform entirely rather than an in-kind Arrow part, a universal replacement cylinder such as the Kaba Ilco 1539 key-in-knob and lever universal cylinder is the type of part to evaluate.
6) Will an Arrow 550AM-44 tailpiece work on a rim cylinder or an exit device?
No. This tailpiece is cut for Arrow MK Series T and D knobs, not for rim applications. Rim devices use their own tailpiece and cam arrangement, and those cylinders are ordered with the tailpiece orientation specified, such as the Schlage 20-021 with a vertical tailpiece cam or the 20-022 with a horizontal one. Match the tailpiece to the lock type it drives.
7) We want to key our Arrow knobs into a small-format interchangeable core system. Is a tailpiece swap part of that?
No. The Arrow 550AM-44 is a mechanical drive part for MK Series T and D knobs and does not change keying. Moving to an interchangeable core system means changing the cylinder: the BEST 1C Series standard 5-pin core and the BEST Peaks 1CB 150 Series interchangeable core cylinder are core-based products, and the BEST 1CDF is a drill-resistant patented interchangeable core in 7-pin brass. Those set up a rekeyable core program; the 550AM-44 restores original knob operation in an existing lockset.
8) Is there a higher-security cylinder option for an Arrow interconnected lock instead of servicing the existing one?
For Arrow JL interconnected locks, the Medeco 1065140 is a 5-pin retrofit cylinder listed for that lock as well as Emtek handleset and deadbolt outside cylinder use. That is a cylinder-level upgrade path. The Arrow 550AM-44 is a different kind of part - an OEM tailpiece for MK Series T and D knobs, used to restore original operation rather than change the cylinder platform.
9) My opening is a mortise lock, not a knob. What takes the place of the Arrow 550AM-44 there?
Mortise locks use a mortise cylinder with a cam instead of a knob tailpiece. Corbin Russwin offers the 1000 Grade 1 Series mortise cylinder in 1-1/2 inch length with an A02 straight cam, and the 1070 Grade 1 Series 1-1/4 inch 6-pin mortise housing with an A01 cloverleaf cam. Adams Rite also lists the 4036 mortise cylinder as Grade 1 with a five-pin plug. The 550AM-44 has no role in those locks; it serves Arrow MK Series T and D knobs.
10) Does the Arrow 550AM-44 come with keys?
The 550AM-44 is a tailpiece - a mechanical replacement part, not a keyed cylinder, so keys are not part of it. If you need a keyed unit supplied with keys, the Falcon A23161-05 G key-in-lever cylinder is a RU/T Series 6-pin G keyway cylinder keyed different with two cut keys, and the Schlage 20-021 rim cylinder ships with two keys.
11) Is the Arrow 550AM-44 rated for commercial door traffic?
It is a commercial-grade part, sold for mechanical lock service in offices, schools, healthcare, retail, multi-tenant residential, government buildings, and industrial facilities. For a property manager standardizing MK Series knob repairs across a portfolio, this is the OEM tailpiece to stock.
12) How many options do I have to specify when ordering the Arrow 550AM-44?
None. The 550AM-44 ships as a single part with no finish, handing, or length choice to make. The only decision on your end is whether the lockset is a standard MK Series T or D knob rather than the Hotel Function.
How fast can I get the Arrow 550AM-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 550AM-44 come with a warranty?
Absolutely. The Arrow 550AM-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 550AM-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 550AM-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.
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