Product and application brief
Carriage bolts combine a smooth rounded head with a short square neck beneath it and a machine-threaded shank. The square neck is the key identifying feature. This range includes standard-reference patterns and drawing-based variations for mating components.
Product forms and reference names
| Product form / field | Reference and distinguishing details |
|---|---|
| Metric round-head square-neck bolts | DIN 603 is a familiar product reference. Bossard BN 30401 describes the square-neck form with partial or full threading; BN is a Bossard catalog code, not an additional standard. |
| Inch-series carriage bolts | ASME B18.5 covers round-head bolts in inch series. Specify the applicable head/neck form, inch thread and edition; a metric label is not an interchangeable inch specification. |
| Large-head historical reference | ISO 8677:1986 describes cup-head square-neck bolts with a large head, product grade C. ISO marks this document withdrawn; it must not be presented as a current universal replacement for DIN 603. |
| Full and partial thread variants | Both belong to the carriage-bolt family. The threaded length, plain shank and neck dimensions distinguish the selected part. |
Head and square-neck geometry
State head diameter and height, square-neck width and height, and the shank diameter. A round head without a square neck belongs to a different construction. The mating hole or recess should be defined by the component drawing.
Reading a size designation
A notation such as M10 × 60 identifies nominal metric thread diameter and stated length, but is not a complete part definition. Add thread pitch, the length measurement convention, threaded length, standard and material or property class. This example is not a stock or availability claim.
Materials, finishes and assembly contents
Identify the required steel or stainless designation and any mechanical-property specification. List zinc plating, galvanizing or another selected finish separately. State whether nuts and washers are included; a bolt-only catalog item does not imply an assembly.
Specification fields
| Product form / field | Reference and distinguishing details |
|---|---|
| Reference | DIN 603, selected inch-series reference or controlled drawing, with edition/revision. |
| Thread | Metric or inch series, diameter, pitch and fit where specified. |
| Length | Length convention, total specified length, threaded length and plain-shank requirement. |
| Head / neck | Head diameter/height; square-neck width/height and relevant tolerances. |
| Material / finish | Material designation or property class and coating requirements. |
| Assembly / quantity | Bolt only or defined nuts/washers, quantity in pieces or assemblies. |
Common product questions
Is a carriage bolt a coach screw?
No. A carriage bolt has a machine thread and a rounded head with a square neck. A coach screw has a different head and thread construction.
Are DIN 603 and ISO 8677 automatically equivalent?
No. ISO 8677:1986 identifies a large-head form and is withdrawn. Compare the specified head, neck, thread and dimensions rather than assuming interchangeability.
Does M10 × 60 define the complete bolt?
No. The notation still needs a product reference, pitch, thread length, head/neck dimensions and material requirements.
Related bolt types
Product references
References checked 5 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.