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Polished brass knob spindle kit with two screws per knob and threaded swivel spindle

Marks USA

Marks USA K9290-3 Polished Brass Knob Spindle Kit door lock

SKU CH-AZ3M-7F57R MPN K9290-3

Polished brass knob spindle kit with threaded 9/32" swivel spindle and two screws per knob for 91A Metro mortise locksets

  • Surface finishPolished Brass
  • Sold asBox
  • Product typeDoor Knob
  • Key featuresTwo screws in each knob
  • Design styleKnobs
  • Polished Brass finish resists corrosion and matches period hardware
  • Two screws per knob secure the trim against daily use
  • 9/32" x 4-3/4" threaded swivel spindle fits 91A Metro mortise locks
  • Replacement kit restores original function without replacing the full lockset
  • Sold as a complete box for straightforward installation

Replacement Trim for 91A Metro Mortise

This polished brass knob spindle kit serves as direct replacement trim for the 91A Metro mortise lockset. It is intended for homeowners or maintenance staff restoring original hardware on existing doors. The kit matches the factory finish and mounting pattern of the specified series. Buyers needing a different finish or a lockset for a new door installation cannot use this item.

Mechanical Operation and Durability

The threaded swivel spindle measures 9/32" by 4-3/4" and engages the mortise cylinder through normal handle rotation. Two screws per knob secure the trim firmly to the door face. No electronic components, batteries or lubrication schedules are involved. The solid brass construction resists corrosion under typical indoor conditions.

Installation Hardware Included

Each knob arrives with its own pair of mounting screws, so no separate fastener purchase is required. The spindle threads directly into the lock body without adapters or specialised tools. The kit contains only the trim pieces shown; the mortise cylinder, strike plate and door-prep template are not supplied.

How it compares

Measured against everything we stock in Door Lock Sets & Deadbolts, at today’s prices. Recalculated every night.

Price $42.99
Cheaper than about 55% of the 2,145 comparable items (median $55.99).

Specifications

Product
Brand nameMarks
Product lineK9290/3 For 91A Metro Series
Model nameK9290-3
Product typeDoor Knob
Design styleKnobs
Size & build
Surface finishPolished Brass

Questions about this item

How do I install the 9/32" x 4-3/4" threaded swivel spindle on the Metro mortise lockset?

Remove the old knob and spindle, insert the new 9/32" x 4-3/4" threaded swivel spindle through the lock body, then secure each polished brass knob with the two screws provided per knob.

What maintenance will the polished brass finish and two-screw knobs need over time?

Polish the brass finish occasionally with a soft cloth and brass cleaner to prevent tarnish; check and tighten the two screws in each knob periodically to keep the trim secure.

What is the first limit that appears under sustained use of the 9/32" threaded swivel spindle?

The 9/32" threaded swivel spindle can develop thread wear or loosening under heavy repeated operation, which typically shows up before the polished brass knobs or screws fail.

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