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Crown-Nut® Tube Inserts

Specialinsert® Tube Hardware

Crown-Nut® Tube Inserts

Fast, Weld-Free Threaded Seats for Round and Square Tubing

The Crown-Nut® is a revolutionary press-in insert designed to create strong, threaded seats at the ends of round and square metal or non-metallic tubes.

By eliminating the need for welding or crimping, Crown-Nuts provide a fast, cost-effective, and aesthetically flawless anchoring solution. They are highly popular for attaching adjustable feet, casters, and joining tubular frames in furniture and industrial assemblies.

Assortment of Crown-Nut Tube Inserts

Why Use Crown-Nut®?

  • Forgiving Tolerances: Elastic crowns adapt to variable inner tube diameters (up to 2mm) and welding seams.
  • No Welding Needed: Eliminates expensive, traditional assembly processes like welding and crimping.
  • Flawless Aesthetics: Will not damage or bulge the outer shape of the receiving material.
  • Fast Press-In Fit: Installs instantly with gradual, progressive pressure.

Common Applications

  • Furniture and display structures
  • Mounting adjustable feet and leveling pads
  • Attaching pivoting caster wheels
  • Telescopic tubing assemblies
  • Note: Not suitable for structural loads or stainless steel pipes.

Browse by Tube & Head Style

Find the exact insert for your tube shape. Choose flanged styles for thrust loads (feet/wheels) or flangeless for traction loads and recessed depths.

Round Flangeless Tube Insert

Round – Flangeless (ITT2S)

Ideal for traction stress. The lack of a flange allows you to recess the insert to any depth inside the tube.

View Specs (PDF) →

Round Flanged Tube Insert

Round – Flanged (ITT2T)

Sits flush on the head of the tube. Ideal for handling both thrust and traction stress (adjustable feet).

View Specs (PDF) →

Square Flangeless Tube Insert

Square – Flangeless (ITQ2S)

Engineered specifically for square tubing. Recess to any depth for hidden traction-load fastening.

View Specs (PDF) →

Square Flanged Tube Insert

Square – Flanged (ITT2Q)

Caps off the end of square tubing perfectly for receiving adjustable feet and preventing tube crush.

View Specs (PDF) →

Caster Wheel Socket Insert

Caster Sockets

Quick press-in sockets engineered with the specific 11.3mm diameter needed to receive pivoting caster wheels.

View Specs (PDF) →

Telescopic Tube Spring

Quick Springs (QS)

Spring-loaded locking buttons designed specifically for rapid adjustment of telescopic tubes.

View Specs (PDF) →

Installation & Tooling

Crown-Nut installation is simple: place the insert inside a punch tool, ensure the crowns are bent toward the punch, and apply gradual, progressive pressure until it reaches the desired depth.

Specialinsert® Tube Hardware

Crown-Nut® Tube Inserts

Fast, Weld-Free Threaded Seats for Round and Square Tubing

The Crown-Nut® is a revolutionary press-in insert designed to create strong, threaded seats at the ends of round and square metal or non-metallic tubes.

By eliminating the need for welding or crimping, Crown-Nuts provide a fast, cost-effective, and aesthetically flawless anchoring solution. They are highly popular for attaching adjustable feet, casters, and joining tubular frames in furniture and industrial assemblies.

Assortment of Crown-Nut Tube Inserts

Why Use Crown-Nut®?

  • Forgiving Tolerances: Elastic crowns adapt to variable inner tube diameters (up to 2mm) and welding seams.
  • No Welding Needed: Eliminates expensive, traditional assembly processes like welding and crimping.
  • Flawless Aesthetics: Will not damage or bulge the outer shape of the receiving material.
  • Fast Press-In Fit: Installs instantly with gradual, progressive pressure.

Common Applications

  • Furniture and display structures
  • Mounting adjustable feet and leveling pads
  • Attaching pivoting caster wheels
  • Telescopic tubing assemblies
  • Note: Not suitable for structural loads or stainless steel pipes.

Browse by Tube & Head Style

Find the exact insert for your tube shape. Choose flanged styles for thrust loads (feet/wheels) or flangeless for traction loads and recessed depths.

Round Flangeless Tube Insert

Round – Flangeless (ITT2S)

Ideal for traction stress. The lack of a flange allows you to recess the insert to any depth inside the tube.

View Specs (PDF) →

Round Flanged Tube Insert

Round – Flanged (ITT2T)

Sits flush on the head of the tube. Ideal for handling both thrust and traction stress (adjustable feet).

View Specs (PDF) →

Square Flangeless Tube Insert

Square – Flangeless (ITQ2S)

Engineered specifically for square tubing. Recess to any depth for hidden traction-load fastening.

View Specs (PDF) →

Square Flanged Tube Insert

Square – Flanged (ITT2Q)

Caps off the end of square tubing perfectly for receiving adjustable feet and preventing tube crush.

View Specs (PDF) →

Caster Wheel Socket Insert

Caster Sockets

Quick press-in sockets engineered with the specific 11.3mm diameter needed to receive pivoting caster wheels.

View Specs (PDF) →

Telescopic Tube Spring

Quick Springs (QS)

Spring-loaded locking buttons designed specifically for rapid adjustment of telescopic tubes.

View Specs (PDF) →

Installation & Tooling

Crown-Nut installation is simple: place the insert inside a punch tool, ensure the crowns are bent toward the punch, and apply gradual, progressive pressure until it reaches the desired depth.

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