“I needed to add a bracket to a metal cabinet where there was no way to hold a nut on the inside. These made the job straightforward.”
— Mike R.
25-Piece Jack Nut Kit for Hollow Walls & Thin Metal
25pcs M4 × 20mm / Buy 1 Kit(25 Jack Nuts)
Sale price
$39.99
Regular price $79.98
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25-Piece Jack Nut Kit for Hollow Walls & Thin Metal
Sale price
$39.99
Regular price $79.98
Save 50% · $39.99 today
25-Piece Hollow-Wall Anchor Kit. Create a Secure Threaded Mount—Even When You Can’t Reach the Back. These collapsible metal jack nuts slip into a pre-drilled hole, then open behind thin or hollow material as you tighten. The result is a practical threaded anchor for brackets, panels, fixtures, and everyday...
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A closer look
Everything you need to know
Explore the details, features, and practical reasons this find deserves a place in your everyday life.
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25-Piece Hollow-Wall Anchor Kit
Create a Secure Threaded Mount—Even When You Can’t Reach the Back
These collapsible metal jack nuts slip into a pre-drilled hole, then open behind thin or hollow material as you tighten. The result is a practical threaded anchor for brackets, panels, fixtures, and everyday repairs.
See the grip form
Insert. Tighten. Let the Legs Lock In.
The four metal legs collapse outward behind the surface, helping spread the hold where an ordinary nut would be impossible to position.
Why DIYers keep them nearby
A Smarter Fix for Thin, Hollow Materials
Backside-Free Setup
Work from the front of the panel when the reverse side is enclosed or hard to reach.
Four-Leg Expansion
The metal body opens behind the wall as the screw tightens, creating a broad mechanical grip.
Reusable Threaded Point
Once properly set, the anchor provides a threaded mounting point for compatible machine screws.
Four Useful Sizes
Choose among M4×20, M5×25, M6×25, and M6×30 25-piece sets for the job at hand.
The mechanics are simple
The Hold Forms Behind the Surface
Drill the correct hole
Match the hole to the selected anchor size and keep the opening clean and round.
Insert the anchor
Seat the flange flat against the front surface with the collapsible body inside the cavity.
Tighten until set
As the screw draws forward, the four legs open behind the material. Stop when the anchor is snug—do not overtighten.
Attach your hardware
Use the compatible threaded point to mount the intended bracket, panel, or light-duty fixture.
Made for the repair drawer
Compact Metal Anchors, Clear Working Geometry
Where they workThin hollow sections such as sheet metal, hollow square tube, and suitable board materials with clearance behind the surface.
What each set includes25 matching jack nuts in the selected size.
Finish and structureSilver-colored metal body with a round flange, internal thread, and four collapsible legs.
Good to knowHole diameter, material thickness, and installed load all affect the result. Confirm fit for your specific project before final installation.
Choose the right set
Four 25-Piece Options
M4×20 mm · M5×25 mm · M6×25 mm · M6×30 mm
Each option is a separate 25-piece set. Select the thread size and body length that match your pre-drilled hole, material thickness, and compatible screw.
From the workbench
Small Hardware That Solves Awkward Mounting Jobs
“The sample fit in my sheet-metal test panel exactly the way I expected. I liked being able to check the size before committing to the repair.”
— Dennis K.
“Sorting the sizes before starting saved me a lot of trial and error. The four-leg body is easy to identify once you have it in hand.”
— Lauren P.
“I used one for a small hook on a hollow patio post. The flush front looks neat, and I didn’t have to open the post to reach the back.”
— Aaron T.
Before you choose
Frequently Asked Questions
What is this type of fastener called?
It is commonly called a jack nut, collapsible nut, or hollow-wall threaded anchor. Its metal legs expand behind thin or hollow material as the screw is tightened.
Do I need access to the back of the panel?
No. The anchor is inserted and set from the front, which makes it useful when the reverse side is enclosed.
Which materials can I use it with?
It is intended for suitable thin or hollow materials with clearance behind the surface, including many sheet-metal and hollow-section projects. Always test the hole size and material condition first.
How do I choose between M4, M5, and M6?
Match the thread size and body length to your compatible screw, pre-drilled hole, material thickness, and project requirements. The available sets are M4×20, M5×25, M6×25, and M6×30.
Can I keep tightening for a stronger hold?
No. Tighten only until the anchor is fully set and snug. Overtightening can damage the anchor or the surrounding material.
Are these rated for heavy structural loads?
No structural load rating is provided. Use them for appropriate light-duty mounting and repair tasks, and select a rated fastening system when the application is safety-critical or load-sensitive.
Project-Ready Support
If your set arrives damaged, incomplete, or different from the size you selected, contact our support team with your order details. We’ll help review the issue and provide the appropriate next step under the store’s return and replacement policy.
A small part that unlocks difficult repairs
Build a Threaded Mount Where an Ordinary Nut Can’t Go
Choose the 25-piece size that fits your project and keep a dependable hollow-material solution within reach.
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Good to know
Frequently asked questions
Where do you deliver?+
We offer worldwide delivery. Use the country and currency selector in the header to view the experience available for your destination.
How can I track my order?+
Tracking details are provided after dispatch when they become available. You can also use our tracking page or contact support for help.
When will my order arrive?+
Delivery timing depends on the destination and shipping option. Available details are shown during checkout and in your tracking updates.
What if I need help with my order?+
Contact our support team with your order number and we will help you review the next step.