Simpson 1" Coupler Nut with Witness Hole by Simpson is engineered to connect threaded rods to one another and to anchor bolts in structural and construction applications. Designed to exceed the specified minimum tensile capacity of the corresponding bolts and threaded rod, this 1 in. coupler nut gives installers two built-in reliability features - a positive stop for consistent thread engagement and a Witness hole for visual verification that rods are fully seated - making it a dependable choice for all-thread rod connections where installation confidence matters.

Key Features

• Witness hole for visual rod verification - tighten the two rods until each all-thread rod is visible in the Witness hole, giving installers an immediate, on-the-spot confirmation that rods are properly installed and fully engaged.
• Positive stop feature - helps ensure even and proper thread engagement into each end of the nut, eliminating guesswork and reducing the risk of under-threading during installation.
• Exceeds minimum tensile capacity of corresponding bolts and threaded rod - provides a connection point that meets or surpasses the strength demands of the rods being joined, supporting structural reliability.
• Designed for non-hot-dip galvanized all-thread rod only - knowing the correct rod type upfront prevents costly compatibility mismatches on the job site.
• 1 in. rod diameter with a minimum height of 2-1/4 in. - sized appropriately for heavy-duty threaded rod connections where a full-engagement nut length is required.
• Available in Zinc Plated or Uncoated finish - lets buyers select the surface treatment that best suits their project environment and corrosion-protection requirements.

Why This Product

• Built-in installation verification - the Witness hole is a practical, no-extra-tools feature that lets installers visually confirm proper rod seating on the spot, reducing the chance of under-engaged connections going undetected.
• Consistent, repeatable thread engagement - the positive stop ensures both rods thread evenly into each end of the coupler nut, supporting uniform load transfer across the connection without relying solely on installer judgment.
• Strength you can count on - Simpson engineered the CNW coupler nut to exceed the specified minimum tensile capacity of the corresponding bolts and threaded rod, so the nut is never the weak point in a threaded rod assembly.
• Clear compatibility guidance - with finish options and explicit rod-type requirements stated upfront, specifiers and contractors can quickly identify the right nut for their application and avoid field substitutions.

Specifications

• Manufacturer: Simpson Strong-Tie
• MPN: CNW1
• Bolt/Rod Diameter: 1 in.
• Height (min.): 2-1/4 in.
• Coating/Finish: Zinc Plated or Uncoated

Options

• Available in standard strength and high strength depending on corresponding rod in use
• Couplers available with oversized threads on one end for installation on hot-dip galvanized bolts (See OST models for ordering)
• OST couplers are typically oversized on one end of the coupler nut only and will be marked with an "O" on oversized side

Frequently Asked Questions

What is the purpose of the Witness hole on the CNW1 coupler nut?

The Witness hole serves as a visual verification point. When the two threaded rods are tightened until each all-thread rod is visible in the Witness hole, installers can confirm that the rods are properly installed and fully engaged within the nut.

What does the positive stop feature do?

The positive stop feature helps ensure even and proper thread engagement into each end of the nut, providing a built-in reference point that promotes consistent installation and helps prevent under-threading.

Is the Simpson CNW1 compatible with hot-dip galvanized all-thread rod?

No. The CNW1 coupler nut is designed for non-hot-dip galvanized all-thread rod only. For use with hot-dip galvanized bolts or rods, see the OST model variants, which feature oversized threads on one end.

What finish options are available for the CNW1?

The CNW1 coupler nut is available in either a Zinc Plated or Uncoated finish.

Note: Product dimensions and/or screw or bolt holes may differ from picture. Please see item description for specifications.