A custom bolt drawing must give the supplier enough information to quote, manufacture, inspect, and pack the part correctly. A simple sketch with “M20 bolt” is not enough for production.

In real sourcing, many custom bolt problems come from missing details. The bolt shape may be clear, but the thread length, tolerance, material, grade, coating, or inspection requirement is not. That creates quotation delays, wrong samples, or failed assembly after delivery.

For drawing-based orders, buyers should treat the drawing as the main technical contract.

Basic Information Every Custom Bolt Drawing Needs

A custom bolt drawing should clearly define the geometry, material, strength, surface finish, and acceptance criteria.

Les acheteurs peuvent comparer les disponibles attaches standards before deciding whether a custom bolt is required.

Critical Dimensions to Mark

Thread and Shank Details

Thread information must be complete. Do not write only “M16” if the thread pitch is important.

Inclure :

• Grand diamètre
• Pas de filetage
• Longueur du fil
• Longueur de tige
• Chamfer or thread start
• Tolérance de filetage si nécessaire
• Exigence d’écrou correspondant

Head and Special Features

For non-standard heads, mark all working dimensions. This includes head height, across flats, socket depth, hole diameter, radius, groove, slot, bend angle, or welded feature.

If the part is not available as a catalog item, fixations non standard sur mesure should be quoted with a complete drawing or approved sample.

Material, Grade and Finish Requirements

Material and strength should not be assumed from appearance.

Pour les applications à charge élevée, consultez attaches à haute résistance and define mechanical testing before production.

Common Drawing Mistakes

Évitez ces problèmes :

1. Missing thread pitch.
2. No tolerance on critical dimensions.
3. Material listed but no strength grade.
4. Coating not clearly defined.
5. No matching nut or washer information.
6. Drawing does not match the physical sample.
7. Revision number missing.
8. No inspection or certificate requirement.

Pour les applications sensibles à la corrosion, comparez attaches enduites avant de confirmer la finition.

Liste de contrôle finale de la demande de prix

Before sending a custom bolt drawing, confirm:

• Drawing version and unit system
• Size, thread, head, and special features
• Material, grade, heat treatment, and coating
• Quantity and tolerance
• Environnement applicatif
• Certificats et rapports d'inspection requis
• Packaging and labeling needs

A good custom bolt drawing reduces guessing. It helps the supplier quote faster, produce more accurately, and inspect the final parts against clear requirements.