The non-standard double-head screws (M5/M6/M8) in the 12.9-level CNC tool turning tool bar accessories are high-strength fasteners used to fix the tool pad or blade. The following are the customization-related matters.
1. Basic parameters
Material: alloy steel 42CrMo or SCM440, heat treatment hardness HRC38-42, surface nitriding or nickel plating treatment (rust-proof + wear-resistant).
Strength grade: 12.9 grade.
Thread specification: double-headed reducing thread; the direction of rotation must be specified; the default is right-handed.
Total length: customized according to the toolbar structure.
2. Structural details
Head design: one end with internal hexagon or external hexagon, the other end without head or cylindrical guide head.
Transition treatment: thread root R angle ≥ 0.2mm (reduce stress concentration).
Key dimensions: effective thread length, polished rod diameter.
3. Process requirements
Thread accuracy: 6g grade (GB/T 197-2018), thread gauge inspection qualified.
Concentricity: Double-end thread axis coaxiality ≤ 0.05mm, ensure assembly without deflection.
Surface treatment: blackening/Dacromet plating, corrosion resistance ≥ 500h salt spray test.
4. Testing standards
Mechanical properties: Tensile test is performed on each batch of samples.
Flaw detection: Magnetic particle flaw detection (no cracks, slag inclusions, and other defects).
Assembly test: Simulate the actual working conditions of the tool bar, repeat disassembly and assembly 10 times without slipping.
5. Packaging and delivery
Rust-proof packaging: vacuum bag + rust-proof paper, 100 pieces/box (with material report label).
Delivery cycle: 3-5 days for samples (can be expedited), 15-20 days for batches.
6. Special needs
3D drawings can be provided for confirmation, and material spectrum analysis reports are supported.
Small batch order (≥50 pieces), non-standard coating (such as Teflon) customization is accepted.
Note: It is recommended to provide a toolbar interface drawing or sample to ensure the matching of the screw and the blade/tool bar.
Through the above design, the non-standard double-headed screw achieves a balance of high strength, high adaptability, and long life in CNC machining, and is a key functional part to ensure machining accuracy and efficiency.
