Cold Heading Forming & Torque Test Specification For Tamper-proof Torx Security Screws, Based On GB/T3098.1 Mechanical Fastener Standard

Cold Heading Forming & Torque Test Specification For Tamper-proof Pin Torx Security Screws, Based On GB/T3098.1 Mechanical Fastener Standard

Tamper-proof pin torx screws block disassembly by ordinary Torx bits via central core pin inside recess, widely used in outdoor charging piles, security cameras, energy storage cabinets and public facilities. Anti-theft performance is determined by two core indicators: Torx recess forming precision and minimum break torque. Ordinary standard Torx screws without central pin cannot meet private disassembly prevention control requirements of public equipment. This article fully covers full-process test standards from head cold heading forming and core pin dimension control to finished anti-theft torque inspection, exclusively explains Torx security threaded parts without cross-category overlapping content.

1. Standard Forming Dimension & Minimum Break Torque For T8~T30 Pin Torx Recess

Security Recess Size	Matching Screw Thread	Central Pin Diameter(mm)	National Standard Min Break Torque(N·m)	Typical Application Scenario
T8 Tamper Torx	M2.5/M3	1.05	0.68	Small Security Camera Housing
T15 Tamper Torx	M3.5/M4	1.42	1.35	Household Energy Storage Cabinet, Charging Pile Panel
T25 Tamper Torx	M5/M6	1.98	2.70	Outdoor High-power Energy Storage Cabinet, Street Lamp Equipment
T30 Tamper Torx	M6/M8	2.45	4.10	Large Industrial & Commercial Charging Pile Base Fixing

2. Standardized Cold Heading Forming Process For Pin Torx Security Recess

1. Head Pre-forming Station: Reserve forming allowance for central core pin, control head coaxiality deviation ≤0.015mm to avoid unilateral stress fracture of eccentric core pin. 2. Precision Recess Stamping Station: Special pin Torx punch forms recess in one stroke with hardness HRC58~62, calibrate punch wear every 30,000 pieces. 3. Deburring Process: Ultrasonic cleaning removes metal debris inside recess; residual debris causes bit slipping and low torque test value. 4. Torque Sampling Test: Extract 50 pieces per batch for break torque test; whole batch is judged worn and punch replaced offline if value below national standard lower limit.

3. Three Mass Production Defect Causes & Mold Rectification Plans For Tamper Torx Recess

1. Broken/missing central core pin inside recess: Shortened core pin of worn Torx punch, insufficient pre-forming head allowance; Rectify: Replace brand-new pin punch, raise pre-forming cavity depth by 0.03~0.05mm. 2. Unqualified min break torque & easy slipping under light twisting: Shallow recess wall, narrow tooth profile from worn punch; Rectify: Extend stamping pressure holding time, repair outer tooth contour of punch, strictly control wire hardness range. 3. Large torque fluctuation within batch & inconsistent anti-theft performance: Offset punch coaxiality, unstable cold heading machine pressure; Rectify: Calibrate punch mold coaxiality, install equipment pressure stabilizer, perform zero calibration every 8 hours.

4. Mandatory Acceptance Standard For Anti-theft Screws Purchased For Outdoor Public Equipment

1. Full central pin security recess is mandatory; ordinary pin-free Torx screws are rejected before warehousing; 2. Outdoor energy storage and charging pile matching models must additionally pass 480h NSS salt spray test without coating peeling or internal recess rust; 3. Break torque test data sheet attached to each batch, whole batch rejected if torque below national standard minimum limit; 4. Only special holed Torx bits can complete disassembly & assembly; ordinary standard Torx bits cannot engage for disassembly to meet security control requirements.