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Satin chrome door knob set with spindle, 2600/26D model

Progressive Hardware Co., Inc.

Progressive Hardware Co., Inc. 2600/26D Satin Chrome Door Knob Set

SKU CH-PD51-N84QH

Satin chrome solid brass knob set with spindle fits Marks surface-mount mortise locksets

  • FinishSatin Chrome
  • Selling UnitEach
  • TypeDoor Knob
  • Satin Chrome finish resists wear and matches modern décor
  • 2-1/4" solid brass knob delivers substantial feel and lasting durability
  • Includes case-hardened set screws and 3-1/2" straight spindle for secure installation
  • 20 TPI standard spindle threads ensure compatibility with Marks 91A and 71A mortise locksets
  • Trusted replacement choice for over 60 years across multiple lock brands

Door Knob Set for Marks Mortise Locks

The Progressive 2600/26D satin chrome knob set is built for Marks surface-mount mortise locksets including the 91A and 71A types. Solid brass construction provides durability for residential and light commercial doors. Supplied as a pair with a 3-1/2" straight spindle and case-hardened set screws.

Direct Replacement for Aged Hardware

This set replaces worn or missing original knobs on compatible Marks mortise locks without modifying the door. The jump is worth it when existing hardware binds, finishes have deteriorated, or spindle threads no longer hold. Over 60 years as the most popular replacement confirms fit and reliability.

2-1/4" Diameter With 20 TPI Spindle

The 2-1/4" knob diameter suits standard bore spacing on mortise lock installations. Standard 20 TPI spindle threading matches factory specifications for secure engagement. Capacity runs out on non-Marks mortise brands, tubular latchsets, or doors prepped for cylindrical locksets requiring different spindle dimensions.

Highlights

  • Satin Chrome finish resists wear and matches modern décor
  • 2-1/4" solid brass knob delivers substantial feel and lasting durability
  • Includes case-hardened set screws and 3-1/2" straight spindle for secure installation
  • 20 TPI standard spindle threads ensure compatibility with Marks 91A and 71A mortise locksets
  • Trusted replacement choice for over 60 years across multiple lock brands

Specifications

FinishSatin Chrome
Selling UnitEach
TypeDoor Knob

Questions about this item

What spindle thread pitch does the 2600/26D knob set require for a Marks surface-mount mortise lock?

The set includes a 3-1/2" straight spindle with 20 TPI threading, matching Marks 91A and 71A surface-mount mortise locksets.

Which screws secure the knobs to the spindle, and what is the common installation error?

Case-hardened set screws fasten each knob to the spindle; the frequent mistake is not tightening them fully, causing the knob to rotate without retracting the latch.

How often should the spindle and set screws be inspected or replaced on this solid brass knob set?

Inspect the 20 TPI spindle and case-hardened set screws annually for wear or loosening; replace if threads strip or screws no longer hold the knobs firmly.

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