Specializing in the production of special precision screws and nuts of various standards such as Chinese standard GB, Japanese standard JIS, British BS, American ANSI and ISO.
At present, the smallest screw diameter that our company can produce is 0.4mm, the shortest is 0.4mm, and the longest is 300CM.
2025-05-30 13:58:06
The Left Hexagon Socket Shoulder Screw is a precision-engineered fastener combining a hexagonal drive system with an unthreaded shoulder section. Its primary technical specifications include:
Drive Type: Internal left-hand hexagon socket (typically conforming to DIN 912/ISO 4762 standards)
Shoulder Diameter: Precision-machined to ±0.025mm tolerance for bearing applications
Thread Specifications: Available in metric (M3-M24) and imperial (1/4"-1") sizes with class 6g/6H thread fit
Material Strength: Typically grade 12.9 alloy steel (tensile strength ≥1220 MPa) or A2/A4 stainless steel (tensile strength ≥700 MPa)
Surface Treatment: Options include black oxide (3-5μm), zinc plating (5-8μm), or geomet® coating (10-15μm)
Torque Capacity: M6 size can withstand 10-12 Nm when properly lubricated
The left-hand thread design provides counter-clockwise tightening, making it ideal for applications where right-hand rotation might cause loosening. The shoulder section serves multiple functions:
Provides precise axial alignment with 0.01-0.03mm runout tolerance
Acts as a wear surface with hardness typically HRC 35-45
Eliminates thread damage in sliding applications through Ra 0.8-1.6μm surface finish
Used in centrifugal pumps (API 610 compliant) and turbine assemblies (ASME PTC 6) where reverse rotation occurs. The left-hand thread prevents loosening under 3000-15000 RPM operational speeds.
Critical in wheel hub assemblies (SAE J2530) and driveline components. The shoulder provides 0.002-0.005" radial clearance for precise bearing preload.
Manufactured to NASM 21272 standards for flight control systems. Special A286 superalloy variants maintain strength at 650°C continuous service.
Used in surgical robotics (ISO 13485) with electropolished 316LVM stainless steel (Ra ≤ 0.4μm) for cleanroom compatibility.
Essential for linear guide systems (JIS B1192), providing ±0.01mm positional repeatability in SCARA robots.
Use ISO 1179-1 compliant hex keys with ±2% size tolerance
Apply MIL-PRF-81309G lubricant for torque values 15-20% below dry conditions
Maintain 0.5-1.5Nm preload torque for most applications
Inspect every 500 operating hours for thread deformation ≥10%
Check shoulder wear using Mitutoyo 543-790B bore gauges (±0.001mm accuracy)
Replace at 0.05mm shoulder diameter reduction
For marine environments, apply DIN 50938 compliant zinc-nickel plating
Use 3% nitric acid passivation for stainless steel variants
Implement ASTM B117 salt spray testing every 1000 hours
High-speed applications: Kluberplex BEM 41-132 every 200 hours
High-temperature: Molykote PG-650 every 500 hours
Cleanroom: perfluoropolyether (PFPE) lubricants
Common failure modes and detection methods:
Thread galling: Detect via 30% torque increase during removal
Shoulder scoring: Visible at Ra > 3.2μm surface roughness
Hydrogen embrittlement: Test per ASTM F1940 after plating
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