The Simpson CNW1-7/8 Coupler Nut with Witness Hole by Simpson is engineered to connect threaded rods to one another and to anchor bolts, accommodating a transition from a 1 in. diameter rod on one end to a 7/8 in. diameter rod on the other. Designed to exceed the specified minimum tensile capacity of the corresponding bolts and threaded rod, this reducer coupler nut includes a positive stop to help ensure even threading into each end of the nut and a Witness hole as a reliable means to verify when rods are properly installed. Compatible with non-hot-dip galvanized all-thread rod only, it suits a range of structural connection applications where secure rod-to-rod or rod-to-anchor-bolt transitions are required.

Key Features

• Witness hole for visual installation confirmation - tighten the two rods until each all-thread rod is visible in the Witness hole, giving you a clear, reliable check that both rods are fully and evenly engaged before completing the connection.
• Positive stop design - helps ensure even threading into each end of the nut, reducing the risk of uneven engagement and supporting consistent, dependable load transfer across the joint.
• Exceeds specified minimum tensile capacity - built to surpass the tensile requirements of the corresponding bolts and threaded rod, providing a connection point that does not become the weak link in the assembly.
• Reduces rod diameter from 1 in. to 7/8 in. - allows a direct transition between two different rod sizes in a single compact coupler, simplifying connections where mixed-diameter rods meet.
• For non-hot-dip galvanized all-thread rod only - clearly defined compatibility helps ensure proper fit and performance, keeping the selection process straightforward for the correct application.

Why This Product

• Built-in verification means no guesswork at installation - the Witness hole lets you visually confirm that each threaded rod is properly seated inside the coupler nut, reducing the chance of an under-engaged connection going undetected in the field.
• Handles mixed rod sizes in one piece - by joining a 1 in. rod to a 7/8 in. rod, this coupler nut eliminates the need for intermediate adapters or workarounds when transitioning between standard rod diameters.
• Strength you can count on for structural connections - designed to exceed the specified minimum tensile capacity of the corresponding bolts and threaded rod, the CNW1-7/8 is suited for applications where connection integrity is critical.
• Available in zinc plated or uncoated finish - offers flexibility to match the corrosion-protection requirements of the surrounding assembly, whether a coated or bare finish is appropriate for the environment.

Specifications

• MPN: CNW1-7/8
• Brand: Simpson Strong-Tie
• Bolt/Rod Diameter: 1 in. to 7/8 in.
• Height (min.): 2-3/8 in.
• Coating: Zinc Plated or Uncoated
• 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 CNW1-7/8 coupler nut?

The CNW1-7/8 features a Witness hole that allows you to visually confirm correct installation. Tighten the two rods until each all-thread rod is visible through the Witness hole, confirming that both rods are fully and evenly engaged inside the nut.

What type of threaded rod is the CNW1-7/8 compatible with?

The CNW1-7/8 is designed for use with non-hot-dip galvanized all-thread rod only. For use with hot-dip galvanized bolts, refer to the OST coupler models, which feature oversized threads on one end.

What rod diameters does the CNW1-7/8 accommodate?

The CNW1-7/8 coupler nut is designed to connect a 1 in. diameter threaded rod on one end to a 7/8 in. diameter threaded rod on the other end, making it suitable for transitioning between these two rod sizes.

What does the positive stop feature do on the CNW1-7/8?

The positive stop is a built-in design element that helps ensure even threading into each end of the coupler nut. It prevents over-insertion of either rod, promoting balanced and secure thread engagement on both sides of the connection.

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