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.
| Barang Gambar | Apa yang Harus Ditentukan | Mengapa Itu Penting |
|---|---|---|
| Nama produk | Custom bolt, anchor bolt, shoulder bolt, U-bolt, etc. | Defines the part type |
| Standard reference | DIN, ISO, ASTM, ANSI, or “made to drawing” | Helps compare with standard fasteners |
| Diameternya | Nominal and actual critical diameter | Controls fit and strength |
| Panjang keseluruhan | Total panjang baut | Affects assembly depth |
| Jarak benang | Metrik, UNC, UNF, atau thread khusus | Mencegah ketidakcocokan mur |
| Panjang benang | Utas penuh atau sebagian utas | Mengontrol keterlibatan |
| Gaya kepala | Hex, square, round, socket, special head | Mempengaruhi perkakas dan izin |
| Bahan | Carbon steel, alloy steel, stainless steel, etc. | Mengontrol kekuatan dan ketahanan terhadap korosi |
| Grade / class | 8.8, 10.9, 12.9, B7, A2-70, etc. | Mendefinisikan kinerja mekanis |
| Permukaan akhir | Zinc plated, HDG, black oxide, Dacromet, plain | Controls corrosion and thread fit |
Pembeli dapat membandingkan tersedia pengencang standar 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.
Termasuk:
- Diameter besar
- Jarak benang
- Panjang benang
- Panjang betis
- Chamfer or thread start
- Toleransi benang jika diperlukan
- Matching nut requirement
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, pengencang non-standar khusus should be quoted with a complete drawing or approved sample.
Material, Grade and Finish Requirements
Material and strength should not be assumed from appearance.
| Persyaratan | Contoh |
|---|---|
| Bahan | 40Cr, SCM440, 304, 316, carbon steel |
| Tingkat kekuatan | Class 8.8, 10.9, 12.9, ASTM A193 B7 |
| Perawatan panas | Quenched and tempered, if required |
| Permukaan akhir | Zinc plated, hot-dip galvanized, Dacromet |
| Test documents | MTC, hardness test, tensile test, inspection report |
Untuk aplikasi beban tinggi, tinjau pengencang berkekuatan tinggi and define mechanical testing before production.
Common Drawing Mistakes
Hindari masalah ini:
- Missing thread pitch.
- No tolerance on critical dimensions.
- Material listed but no strength grade.
- Coating not clearly defined.
- No matching nut or washer information.
- Drawing does not match the physical sample.
- Revision number missing.
- No inspection or certificate requirement.
Untuk aplikasi yang sensitif terhadap korosi, bandingkan pengencang berlapis sebelum memastikan penyelesaiannya.
Daftar Periksa RFQ Akhir
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
- Lingkungan aplikasi
- Sertifikat dan laporan inspeksi yang diperlukan
- 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.