Product and application brief
Square head bolts have an external four-sided head and a threaded shank. The square head, bearing surface and end form distinguish this family; a square neck below a round carriage-bolt head is a different construction. This page groups recognisable product forms under the existing Bolts range. Material, finish and thread size are specification choices within a form, not separate product categories.
Product forms and reference names
| Product form / field | Reference and distinguishing details |
|---|---|
| Inch-series square head bolts | ASME B18.2.1-2012 (R2021) covers inch-series square and hex bolts and screws. Define the selected square-head construction and thread explicitly. |
| Square head bolts with collar | DIN 478:2016-08 describes the collar form, with metric coarse threads M5–M24. The collar geometry is part of the product identity. |
| Square head bolts with short dog point | DIN 479:2016-08 describes a reduced-diameter short cylindrical end, with metric coarse threads M5–M24. Do not substitute a plain end solely because the thread matches. |
| Collar and rounded short dog point | DIN 480:2016-08 describes a collar plus short dog point with a rounded end; its published scope includes metric coarse threads M8–M24. |
| Drawing-based square-head parts | Define the head, collar if present, shank, thread and point on a controlled drawing rather than assigning a standard by appearance. |
Identify the head, collar and point separately
A plain square head, a collar under that head and a short dog point are independent features. DIN 478, DIN 479 and DIN 480 are distinct references, not interchangeable aliases. A dog-point variant may be described as a square-head screw in a catalogue; retain its actual end geometry when translating the product name.
Metric and inch references
Use the original thread designation and units. An inch-series square bolt is not a metric DIN bolt after converting its diameter to millimetres. The applicable edition and detailed dimensional requirements must follow the selected reference or drawing. The ranges above identify standard scopes, not a stock list or a blanket dimensional interchangeability claim.
Specification fields
| Product form / field | Reference and distinguishing details |
|---|---|
| Reference | Selected DIN or ASME edition, customer part number, or drawing revision. |
| Head and collar | Width across flats, head height, and collar diameter and thickness when present. |
| Thread | Metric diameter and pitch, or inch diameter and thread series/TPI; required thread length. |
| Length and shank | State the measurement datum, length, body diameter and any unthreaded portion on the drawing. |
| End form | Plain end, short dog point, or rounded short dog point; specify point diameter and length. |
| Material and finish | Required material designation, property requirements and coating; keep these separate from the dimensional standard. |
| Quantity | Part-specific quantity with units; separate mixed sizes into individual line items. |
Common product questions
Is a square-head bolt the same as a carriage bolt?
No. A square-head bolt has a four-sided external head. A carriage bolt typically has a round head and a square neck underneath it.
Are DIN 478, DIN 479 and DIN 480 interchangeable?
No. They distinguish collar and end constructions. Match the specified geometry and edition, not just the thread diameter.
Can square-head parts be made to a drawing?
Drawing-based variants can be specified with head, collar, shank, thread and point dimensions. Keep departures from a named standard explicit.
Related bolt types
Product references
References checked 6 October 2026 explain product identity. Third-party model names and approvals are not FastenerBridge brand affiliation, stock or certification claims. Final geometry and requirements follow the selected specification.