Barrel Nut
Nuts · cross dowel · cross dowel nut · furniture barrel nut
Definition: A barrel nut is a cylindrical nut with a cross-drilled threaded hole, inserted into a pre-drilled hole to receive a bolt at a right angle in knock-down furniture.
Anatomy
■ Body■ Internal thread
Governing standards: Manufacturer specified (no universal standard)
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| 1/4-20 | M6 | 0.35 dia | 0.55 long |
| 5/16-18 | M8 | 0.43 dia | 0.71 long |
| 3/8-16 | M10 | 0.51 dia | 0.79 long |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Steel | carbon steel, zinc-plated | — | None |
| Stainless / brass | stainless or brass | — | None |
Materials
- Zinc-plated steel
- Stainless steel
- Brass
Pros & Cons
Pros
- Hidden, clean joint from one side
- Strong in the joint axis
- Reusable and re-tightenable
Cons
- Needs accurate cross-drilling
- Spins if the alignment slot is missed
- Specialty hardware, not universal
Typical Uses
- Flat-pack furniture
- Cabinet joints
- Bed frames
- Invisible fastening
Alternatives & Related
- T-Nut — Flanged nut for straight-on bolting in wood
- Hex Nut — Standard nut where access is not a problem
Where to Buy
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FAQ
What is a barrel nut used for?
Joinery in knock-down furniture — the barrel sits in a cross-drilled hole and a bolt threads into it from the adjoining piece at 90 degrees.
How do you align a barrel nut?
Rotate the barrel with a screwdriver in its alignment slot until the threaded hole lines up with the incoming bolt.