定制螺栓图纸中应包含哪些内容？

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.

买家可以比较可用 标准紧固件 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.

包括：

• 大径
• 螺距
• 螺纹长度
• 柄长
• Chamfer or thread start
• 螺纹公差（如果需要）
• 配套螺母要求

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, 定制非标紧固件 should be quoted with a complete drawing or approved sample.

Material, Grade and Finish Requirements

Material and strength should not be assumed from appearance.

对于高负载应用，请查看 高强度紧固件 and define mechanical testing before production.

Common Drawing Mistakes

避免这些问题：

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.

对于腐蚀敏感的应用，比较 涂层紧固件 在确认完成之前。

最终RFQ清单

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
• 应用环境
• 所需证书和检验报告
• 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.