What are standard fasteners? Most people know that it is short for standard fasteners. We will also tell the manufacturer when purchasing standard parts, the name of the product (such as hex head all-thread bolts, hex nuts, etc.), the standard (DIN 931, ISO 3032, etc.), the material (stainless steel 304, carbon steel 8.8 grade, etc.), the size (M10 * 60, etc.) and other needs (plating, salt spray test, etc.), basically the more detailed the said, the faster you find the fasteners.
When buying standard parts, because there are strict standard specifications, sometimes we are not clear about certain information, but we can match them by using the standard number and other relevant information. However, in many cases, standard parts with fixed specifications cannot meet our actual needs, so we need to customize non-standard parts.
For non-standard parts (non-standard fasteners), if we don’t provide complete information, it’s easy to waste money only to end up with something completely different from what you need, resulting in an embarrassing situation where the product doesn’t match the description.
What Are the Advantages of Standard Fasteners?
Standard parts conform to unified standards and specifications, offering advantages such as high versatility, wide variety, short production cycles, and low prices. Due to their standardized production, they can be mass-produced and stockpiled, resulting in ample supply and short delivery times. Meanwhile, the production technology of standard parts is mature, with high stability and reliability, and can meet most engineering needs.
What Are Non-standard Special Fasteners?
Non-standard custom fasteners refer to screws that are not designed and manufactured according to standard parameters. They do not have fixed specifications and dimensions, and can be freely controlled and matched according to the user’s needs. Generally speaking, fastener manufacturers can customize and produce them according to the specific dimensions and specifications required by the customer.
Non-standard features include:
- Special dimensions (length, diameter, thread profile, pitch).
- Special head or slot types (hexagonal, square, T-type, countersunk, irregular).
- Special materials (superalloys, titanium alloys, duplex stainless steel, high-temperature alloys).
- Special properties (high strength, high hardness, corrosion resistance, high temperature resistance).
- One-piece molded structural components (bolt + washer combination, non-standard flange heads).
- Custom per drawing
How to Customize Non-standard Fasteners?
Many customers who order non-standard screws for the first time have a question: Why is the lead time for custom non-standard screws so long? Below is a detailed introduction to the entire process of customizing non-standard screws:
Step1: Define Requirements
Before customizing non-standard parts, we need to be clear about the occasion in which the desired non-standard parts will be used, what they will be used to fasten, what effect we want to achieve after using them, whether they need to be tamper-proof, and whether they need to conform to the product appearance.
Parameters:
- Thread Specifications (UNC/UNF/BSW/Left-hand Thread/Metric Thread/Special Thread)
- Length, Dimensions, Fit Tolerances
- Carbon Steel: 4.8 / 8.8 / 10.9 / 12.9
- Alloy Steel: ASTM A193 B7 / B7M / L7 / L7M
- Stainless Steel: A2-70 / A4-80 / 316 / 904L
- Corrosion-resistant Steel: Super Duplex, Monel, Inconel
- Temperature (e.g., -60°C, 450°C, 700°C)
- Humidity, pH
- Seawater, Salt Spray, Chemical Media
- CAD/PDF Drawings
- Application Scenarios
Step1: Manufacturing Process
| Process Type | Applicable | Pros and Cons |
|---|---|---|
| Cold Forging | Mass production of bolts and screws | High strength and high efficiency; high mold cost |
| Hot Forging | Large-size, high-strength bolts, flange head bolts | Complex head shape |
| CNC machining | Small batches, multiple specifications, precision parts | High precision, high cost |
| Turning + Milling + Threading | Studs, special structural components | Suitable for non-standard |
Step3: Design Drawings
The appearance, specifications, dimensions, head shape, and groove shape of non-standard parts are designed according to product requirements, and the material and surface treatment method are determined in combination with their usage environment.
Note: For custom-made non-standard parts, the customer needs to provide drawings and indicate the specifications, dimensions and requirements of each part on the drawings. If no drawings are available, a sample of the non-standard part needs to be provided so that the manufacturer can design drawings and produce a sample based on the sample; or the actual needs can be explained to the manufacturer in detail so that the manufacturer can design drawings based on the actual situation.
Step4: Prototyping
Produce samples according to the drawings. If non-standard parts require mold production, then the mold needs to be customized before production.
After sampling, we need to test the samples in actual applications, such as on the product itself, to see if they are suitable. If they are suitable, then we will confirm mass production.
Compared to standard parts production, this entire process involves additional steps such as design drawings, mold customization, and sample confirmation, which takes a considerable amount of time. If the customer has additional requirements such as salt spray testing, tensile strength testing, or third-party performance testing, the time will be even longer. Time must also be allocated for unforeseen circumstances, so the lead time for custom non-standard screws is generally much longer than that for standard parts.
Characteristics of Non-standard Parts
Non-standard parts are characterized by being designed and manufactured according to specific engineering requirements, thus possessing strong personalization and good applicability. Non-standard parts can be designed and manufactured according to user needs, which can meet the requirements of some special projects. Furthermore, the structure, materials, and processes of non-standard parts can be customized as needed, thus offering high flexibility.
Non-standard Fastener Types
Non-standard fasteners are bolts, nuts, screws, studs, washers, pins, and various special parts that do not conform to international standards (ISO, DIN, GB, ASME, ASTM, etc.).
- Non-standard bolts: Extended head bolts, special-shaped flange bolts, extra-long bolts (500mm~2000mm), fine thread bolts, double-ended bolts.
- Non-standard nuts: Thickened nuts, large diameter nuts (M52~M150), precision thin nuts.
- Non-standard screws: Special-shaped heads, special groove types (Torx/square groove/combination groove), hardened tips.
- Non-standard washers: Enlarged outer diameter (OD), extra-thick design, special material washers.
- Other custom parts: Specially machined parts, welded bolts, non-standard assemblies.
