Hex Head Bolt Fine Thread Fully Threaded — Metric Sizes
What Is a Fully Threaded Fine Thread Hex Head Bolt?
A fully threaded fine thread hex head bolt is a fastener with a six sided head and a fine pitch thread that runs the full length of the shank. The hex head gives a solid grip for a wrench or socket, so you can apply high torque cleanly. The fine thread has more threads per length than a coarse thread of the same diameter, which gives a stronger grip in the mating thread, finer control when adjusting, and better resistance to loosening under vibration. Being fully threaded lets the bolt clamp at almost any grip length. These bolts are a common pick for machinery, automotive work, structural connections, and precision assemblies, and are offered in plated steel and A2/A4 stainless.
Key Features and Benefits
- Six Sided Hex Head: The hex head gives a firm wrench or socket grip so you can apply high torque cleanly.
- Fine Pitch Thread: The finer thread gives extra holding power, finer adjustment, and better vibration resistance.
- Fully Threaded Shank: Threaded along the full length so the bolt can clamp at almost any grip length.
- High Torque Capacity: The solid head and fine thread suit connections that need firm, controlled tightening.
- Steel and Stainless Options: Plated steel for general use and A2/A4 stainless for corrosion resistant service.
Materials and Finishes
- Carbon Steel (Zinc Plated): Standard plated finish for general assembly and indoor use.
- Brass: For electrical, instrument, and decorative work where conductivity or a brass finish is wanted.
- Stainless Steel (A2 / A4): For marine, outdoor, and corrosion prone environments.
Standards Compliance
- DIN 961 — Hexagon head bolts with fine pitch thread, fully threaded
- ISO 8676 — Hexagon head screws with fine pitch thread
- ISO 262 — Metric fine thread pitch
Size Range and Availability
Available in M8 through M24 in metric fine thread, in plated carbon steel and A2/A4 stainless steel.
Frequently Asked Questions (FAQs)
1. What is a fine thread hex bolt used for?
It is used in machinery, automotive work, structural connections, and precision assemblies where extra holding power, finer adjustment, and vibration resistance are wanted.
2. What is the difference between fine thread and coarse thread?
A fine thread has more threads per length and a shallower pitch than a coarse thread of the same diameter. It grips more thread in the mating part, allows finer adjustment, and holds better under vibration, while coarse thread is faster to run and more tolerant of dirt and damage.
3. What does fully threaded mean?
It means the thread runs the entire length of the shank, with no smooth section under the head. This lets the bolt clamp at almost any grip length and thread fully into deep tapped holes.
4. When should I choose fine thread over coarse thread?
Choose fine thread when you need higher clamp strength for the diameter, precise adjustment, or better resistance to vibration loosening. Coarse thread is the better pick for quick assembly or dirty and rough conditions.
5. Are these bolts available in stainless steel?
Yes. We stock them in A2 and A4 stainless, along with zinc plated steel, for general and corrosion resistant applications.
6. What drive do these bolts use?
They use a six sided hex head driven with a wrench or socket, which suits high torque and repeated tightening.
7. Do fine thread bolts need matching fine thread nuts?
Yes. Fine thread bolts must be paired with fine thread nuts or tapped holes of the same specification. Coarse and fine threads of the same diameter will not fit together.
8. What sizes do you stock for fully threaded fine thread hex bolts?
We stock M8 through M24 in metric fine thread, in plated carbon steel and A2/A4 stainless steel.
