OEM manufacturer ASME B18.2.1 · ASME B18.2.2 · DIN 557
Square Head Bolts & Square Nuts — ASME B18.2.1 / B18.2.2
Square head bolts and square nuts are four-sided fasteners used where a large bearing face and a strong spanner grip are needed. Teshi Group manufactures square bolts to ASME B18.2.1 and square and heavy square nuts to ASME B18.2.2 and DIN 557.
Also called: square bolts, square head bolts, square nuts, heavy square nuts, DIN 557 nuts
What are Square Head Bolts & Square Nuts?
A square head bolt has a four-sided head; a square nut has four flat sides. Compared with hexagon forms, the square shape gives more bearing area against the joined surface and corners that resist rounding when tightened with a spanner. Square nuts also sit in channels and slots without turning. They are used in older plant designs, railway and transmission line hardware, timber construction, channel supports and as replacements on existing equipment built with square fasteners.
Key features
- Square bolts to ASME B18.2.1
- Square and heavy square nuts to ASME B18.2.2; metric square nuts to DIN 557
- Carbon steel, alloy steel and stainless steel grades
- Large bearing face; nut does not rotate in channels
- Plain, zinc or hot-dip galvanised finish
Specification
| Supply | OEM manufacturer — Teshi Group, India, India |
|---|---|
| Standard | ASME B18.2.1 (square bolts), ASME B18.2.2 (square and heavy square nuts), DIN 557 (metric square nuts) |
| Carbon steel | ASTM A307, ASTM A563 nuts, ISO 898 class 4.6 / 5 |
| Alloy steel | ASTM A193 B7 bolts with A194 2H nuts, on request |
| Stainless steel | 304, 316 |
| Threads | UNC, ISO metric coarse |
| Finish | Plain, zinc electroplated, hot-dip galvanised |
| Documents | EN 10204 3.1 mill test certificate (3.2 / third-party inspection when specified), dimensional inspection report |
Applications
- Replacement fasteners on older plant and machinery
- Railway and transmission line hardware
- Strut channel and cable support systems
- Timber and heavy construction
FAQ
Square Head Bolts & Square Nuts: common questions
Why use square nuts instead of hex nuts?
Square nuts have more bearing area and their flat sides stop them turning in slots and channels, so they can be held without a second spanner.
Which standard covers square nuts?
ASME B18.2.2 covers inch square nuts and heavy square nuts, along with the other inch nut types. DIN 557 covers metric square nuts. Square head bolts are covered by ASME B18.2.1.
Can you match old square bolts on existing equipment?
Yes. Send a sample or a drawing showing thread size, length, head size and material grade, and we will manufacture matching square head bolts and square nuts for the existing equipment.
Are square head bolts available in stainless steel?
Yes. Square head bolts and square nuts can be made in 304 and 316 stainless steel for corrosive or outdoor service, as well as in carbon steel and alloy steel grades.
Need a size or grade not listed here?
Our engineering team manufactures against your drawing or datasheet, with dimensional sign-off before dispatch.
Send us your specificationTraceability
From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
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