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العربية Stud bolts are simple parts, but they cause real trouble when the size is written poorly. A buyer may order “3/4 inch stud bolts” and forget the length, thread series, nut grade, coating, or flange standard. That is enough to delay assembly.
A correct stud bolt specification should identify four things first: diameter, length, thread, and matching nuts.
Basic Stud Bolt Size Chart
Common Ordering Fields
| Artículo | What to Specify | Example |
|---|---|---|
| Diámetro | Metric or inch size | M20 or 3/4 in. |
| Longitud | Overall end-to-end length | 150 mm or 6 in. |
| Thread | Pitch or TPI | M20 x 2.5 or 3/4″-10 UNC |
| Material grade | Strength and service rating | ASTM A193 B7, Class 8.8 |
| Nut requirement | Quantity and grade | 2 pcs ASTM A194 2H nuts |
| Finish | Surface protection | Plain, zinc plated, HDG, PTFE |
For general sourcing, stud bolts are often grouped under industrial bolts, especially when supplied with matching nuts and washers.
Diameter and Thread Requirements
Metric and Inch Threads Must Stay Separate
Metric stud bolts use millimeter diameter and pitch. Inch stud bolts use diameter and threads per inch. They are not interchangeable.
| System | Sample Size | Thread Description |
|---|---|---|
| Metric coarse | M16 x 2.0 | 2.0 mm pitch |
| Metric fine | M16 x 1.5 | Finer pitch for tighter adjustment |
| UNC | 3/4″-10 | 10 threads per inch |
| UNF | 3/4″-16 | Fine inch thread |
Oil, gas, flange, and pressure equipment projects commonly use ASTM A193 stud bolts with ASTM A194 heavy hex nuts. Machinery and steel structure projects may use metric classes such as 8.8 or 10.9.
Length Selection
Measure Overall Length
Stud bolt length is normally measured from end to end. Do not include nut height in the stud length. For flange bolting, length should allow full nut engagement on both sides without excessive thread projection.
Check:
- Flange thickness
- Gasket thickness
- Washer use, if required
- Nut height
- Required thread projection
- Coating thickness
Nut and Washer Matching
The Stud Is Only Half the Set
A strong stud bolt needs the correct nut. For B7 studs, 2H nuts are common. For stainless studs, match A2/A4 or ASTM stainless nut grades. If washers are required, select proper size and hardness from washer options.
For nut selection, review industrial nuts and confirm grade, thread, and finish together.
Buyer Checklist
Before placing an order, confirm:
- Metric or inch system.
- Diameter and thread pitch/TPI.
- Overall length.
- Material grade and standard.
- Nut grade and quantity.
- Finish and coating thickness.
- Certificate requirements.
For coated or outdoor applications, compare coated fasteners before finalizing the stud bolt size. A clear size chart prevents wrong fit, weak clamping, and site delays.