Hanger Bolt
Studs & Rods · hanger screw · lag machine bolt
Definition: A hanger bolt has coarse lag threads on one end (into wood) and machine threads on the other (for a nut) — a headless, dual-purpose fastener.
Anatomy
■ Head■ Shank■ Threads■ Point
Governing standards: Manufacturer specified (no universal standard)
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| 1/4-20 x 2 | M6 x 50 | — | lag + machine |
| 5/16-18 x 3 | M8 x 75 | — | lag + machine |
| 3/8-16 x 4 | M10 x 100 | — | lag + machine |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Zinc steel | carbon steel, zinc-plated | — | None |
| Stainless | 304 stainless | — | None |
Materials
- Zinc-plated steel
- Stainless steel
Pros & Cons
Pros
- Combines wood grip and machine thread
- No head to hide
- Strong in wood
Cons
- Needs a pilot hole and a double-nut or driver to install
- Machine end can be over-tightened into soft wood
- Specialty item — not every store stocks it
Typical Uses
- Hanging fixtures from wood
- Furniture legs and feet
- Electrical boxes to beams
Alternatives & Related
- Lag Bolt — Headed fastener for heavier wood connections
- Threaded Rod — Where both ends need machine threads and nuts
Where to Buy
Affiliate links — we may earn a commission at no cost to you.
FAQ
How do you install a hanger bolt?
Drill a pilot hole, lock two nuts together on the machine end, and drive it in by wrenching the outer nut. Or use a hanger-bolt driver bit.
Hanger bolt vs lag screw?
A lag screw has a hex head and threads fully into wood. A hanger bolt has no head — lag threads one end, machine threads the other — so a nut can attach a fixture.