The Simpson CNW3/4 3/4 in. Coupler Nut with Witness Hole from Simpson is engineered to connect threaded rods to one another and to anchor bolts with reliable, verifiable results. Designed to exceed the specified minimum tensile capacity of the corresponding bolts and threaded rod, this coupler nut is built for structural connections where proper thread engagement is critical. A built-in positive stop promotes consistent installation from both ends, while the Witness hole gives installers a clear, visual means to confirm that each rod is seated correctly before the connection is finalized. Intended for use with non-hot-dip galvanized all-thread rod, the CNW3/4 is a straightforward, dependable solution for rod-to-rod and rod-to-anchor-bolt coupling applications.

Key Features

• Witness hole for visual installation verification - tighten the two rods until each all-thread rod is visible in the Witness hole, giving installers immediate, on-the-spot confirmation that both rods have achieved proper engagement without guesswork.
• Positive stop feature - helps ensure proper thread engagement into each end of the nut, promoting even, balanced threading from both sides and reducing the risk of an under-threaded connection.
• Exceeds specified minimum tensile capacity - designed to surpass the tensile requirements of the corresponding bolts and threaded rod, supporting structural confidence in demanding load applications.
• Compatible with non-hot-dip galvanized all-thread rod only - knowing this upfront helps installers select the correct coupler for their rod type and avoid mismatched hardware on the job.
• 3/4 in. rod diameter with a minimum height of 1 3/4 in. - purpose-sized dimensions ensure a proper mechanical fit with 3/4 in. all-thread rod in rod-extension and anchor-bolt connection scenarios.

Why This Product

• Built-in verification means no second-guessing - the Witness hole is a practical, engineered feature that lets installers visually confirm correct rod seating in real time, reducing installation errors on structural connections where thread engagement directly affects performance.
• Designed to exceed tensile capacity requirements - because the CNW3/4 is engineered to surpass the minimum tensile capacity of the corresponding bolts and threaded rod, it supports the integrity of the connected assembly rather than simply meeting a baseline threshold.
• Consistent engagement from both ends - the positive stop helps ensure even threading into each side of the coupler nut, giving contractors and builders a repeatable, reliable result across multiple connections on the same project.
• A trusted Simpson design for rod-extension and anchor-bolt applications - whether extending all-thread rod or connecting rod to an anchor bolt, the CNW3/4 addresses both use cases with a single, purpose-built coupler nut backed by Simpson engineering.

Specifications

• Manufacturer: Simpson Strong-Tie
• MPN: CNW3/4
• Rod Diameter: 3/4 in.
• Height (min.): 1-3/4 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

How do I know when the threaded rods are properly installed in the CNW3/4 coupler nut?

The CNW3/4 features a Witness hole that provides a visual means to verify correct installation. Tighten the two rods until each all-thread rod is visible through the Witness hole, confirming that both rods have achieved sufficient thread engagement.

What is the purpose of the positive stop feature on the CNW3/4?

The positive stop is a built-in design element that helps ensure even, proper thread engagement into each end of the nut. It acts as a physical barrier to promote consistent and balanced threading from both sides of the coupler.

Can the CNW3/4 coupler nut be used with hot-dip galvanized all-thread rod?

No. The CNW3/4 is intended for use with non-hot-dip galvanized all-thread rod only. For hot-dip galvanized rods, Simpson Strong-Tie offers OST model couplers with oversized threads on one end specifically designed for that application.

What is the rod diameter and minimum height of the CNW3/4 coupler nut?

The CNW3/4 accommodates a rod diameter of 3/4 in. and has a minimum height of 1-3/4 in. It is available in 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.