J-Bolt
Bolts · j hook bolt · hook anchor bolt
Definition: A J-bolt is a rod threaded on one end and bent into a J-hook on the other, cast into concrete to anchor sills, plates, and equipment.
Anatomy & Schematic
■ Head■ Shank■ Threads■ Point
Governing standards: ASTM F1554 · ASTM A307
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| 1/4-20 | M6 | — | 4 to 8 long |
| 3/8-16 | M10 | — | 6 to 12 long |
| 1/2-13 | M12 | — | 8 to 16 long |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Grade 36 | low carbon steel | 58,000 | F1554 36 |
| Grade 55 | medium carbon steel | 75,000 | F1554 55 |
Materials
- Zinc-plated steel
- Hot-dip galvanized steel
- Stainless steel
Pros & Cons
Pros
- Strong embedment once concrete cures
- Inexpensive
- Readily available
Cons
- Position must be set before the pour
- Bend section is weaker under pull-out
- Cannot be relocated after curing
Typical Uses
- Sill plate anchoring
- Concrete embedment
- Equipment bases
- Fencing and posts
Alternatives & Related
- Anchor Bolt — Headed or L-shaped for heavier embedment
- Wedge Anchor — Post-installed into cured concrete
Where to Buy
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FAQ
What size J-bolt for a sill plate?
1/2 in diameter is typical for residential sill plates; length depends on embedment and the nut-and-washer stack above. Check local code.
How deep should a J-bolt be embedded?
Generally 7 in minimum embedment for full strength in concrete, but follow the governing code or engineering specification.