Carbon steel, zinc-plated cross-countersunk machine screws are widely used in mechanical assembly, electronic equipment, furniture, and other fields. Below is a detailed explanation of their customization requirements, presented in layers by technical logic.
I. Core Specifications
Thread Specifications
Metric Standards: M2.5, M3, M4, M5, M6, and M8, with full or partial thread options available.
Thread Pitch: Coarse is the default; fine pitch requires specification.
Head Type
Countersunk head: 90° head taper angle, flush mounting
Flat head: Cross recess on top
II. Materials and Surface Treatment
Base material:
Carbon steel grades: 1008/1010 (default), 10B21 (high-strength optional)
Hardness: HRB 70-95 (temperable to HRC 22-32)
Coating: Colored zinc passivation: Thickness 5-8μm, salt spray test ≥ 96 hours (neutral salt spray)
Optional additional requirements: Sealing treatment (enhanced corrosion protection), hydrogen embrittlement-free treatment (mandatory for high-strength steel)
III. Key Dimensional Tolerances
Item Standard (ISO 4762) Customizable Accuracy
Head diameter ±0.1mm ±0.05mm
Cross recess depth ±0.15mm ±0.1mm
Thread tolerance band 6g (default), 4-hour/6-hour service available
IV. Special Request Options
Head Marking:
Laser marking (manufacturer logo, specification number, etc.), embossed/debossed stamping (depth ≤ 0.1mm)
Performance Certifications
Mechanical Properties: Compliant with ISO 898-1 Class 4.8/8.8
Environmental Compliance: RoHS/REACH (material certification required)
Packaging: Bulk (carton/woven bag)
Boxed (PVC box with anti-rust paper, 100-500 pieces per box)
Taping (suitable for SMT automation)
V. Quality Control Key Points
Full Inspection Items: Thread Go/No-Go Gauges, Head Dimensions, Coating Adhesion (cross-cut method)
Sampling Frequency: Salt spray test: ≥ 3 pieces per batch; hardness test: 1 piece per 1,000 pieces
VI. Delivery Time and MOQ
Prototyping Cycle : 3-5 days (3-10 samples available)
Mass production lead time: 15-20 days (<500,000 pieces)
Minimum Order Quantity
Regular specifications: 5,000 pieces/specification
Special sizes/coatings: 10,000 pieces and up
VI. Lead Time and MOQ
Prototyping lead time: 3-5 days (3-10 samples available)
Mass production lead time: 15-20 days (<500,000 pieces)
Minimum Order Quantity: 5,000 pieces/specification
Special sizes/coatings: 10,000 pieces and up
Submitting drawings or samples will prioritize matching to existing molds, reducing mold-making costs. For high-strength applications, we recommend 10B21 material with 8.8-grade treatment.
