ST2.9 self-tapping screws
sheet-metal (ISO 1478)
5 documented uses, taken from manufacturer catalogs, service manuals and teardowns.
Pilot hole
2.4-2.6 mm in 1.0-1.5 mm steel
Too tight and the head snaps or the boss splits; too loose and the thread strips on the first removal.
Buy ST2.9 self-tapping screws
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Watch out for
- Standard PC fan screws are often ST2.9 or ST3.5; ST2.9 is 'Case Fan Screw' standard.
- Most TV, appliance, HVAC and power-tool service documents list only a driver type or a part number, never a thread size - so a screw kit sold as 'fits brand X' is usually a seller's guess, not an OEM spec. Measure the old screw before buying.
Where ST2.9 is used
Bosch Rexroth VarioFlow Plus
Fastening sections and slide rails in conveyor systems
9.5 mm · confirmed · metal brackets
View sourceSupermicro SC829B Chassis
Securing 2U server chassis components and fan brackets
6-10 mm · confirmed · server chassis
View sourceStarTech RK2536BKF Server Rack
Securing panel hinges and door assembly
8-12 mm · confirmed · cabinets
View sourceElement RW-337D Receipt Printer
Housing assembly and internal plate securing
6 mm · confirmed · electronics
View sourceHP ProLiant Server Gen9
Internal air baffle and bracket fastening
6.5 mm · high · server chassis
View source