Gunmetal 903 Set Screws manufactured at TorqBolt are wear and cavitation resistant with excellent impact properties.
Dimensional standards as per DIN 913,DIN 914,DIN 915,DIN 916,DIN 551,DIN 553,DIN 438,BS 4175 are provided.
The raw material of these fasteners is classified as Non-Ferrous Alloys. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. Gunmetal 903 Set Screws are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
Gunmetal 903 Is Hard ,strong, Tough &,wear Resistant & Fine Grained . This Exhibits Good Machinability And Corrosion Resistance To Sea Water. The Addition Of Nickel Increases The Mechanical Strength And Corrosion Resistance. Plain Bearing Shells, Moderately Stressed Slide And Coupling Components. Stern Tubes & Most Often Used For Heavy Loads & Low Speed Bushing.
Gunmetal 903 Set Screws — Specifications & Dimensions
Gunmetal 903 Set screws are externally threaded fasteners typically driven into a tapped hole or self-tapped material. TorqBolt manufactures Gunmetal 903 Set screws per ASME B18.3 (socket products), ASME B18.6.3 (machine screws), DIN 912 / 7991 / 6912, and ISO 4762 / 10642, in metric M3–M48 and imperial 0–1/2".
Drive Types
Hex socket (Allen) — ASME B18.3 / DIN 912, primary for high-torque industrial use
Gunmetal 903 Set screws are available in cap (cylindrical), button (low-profile dome), countersunk / flat (82° or 90°), pan, fillister, truss, and shoulder configurations. Countersunk per DIN 7991 with 90° head angle is standard for metric; 82° per ASME B18.6.3 for imperial.
Thread & Length
Gunmetal 903 Set screws use full-thread or partial-thread (length-under-head) configurations. Machine screws are typically full-thread; cap screws use partial thread for grip control. Threading per ASME B1.1 (UNC/UNF) or ISO 965 (metric coarse/fine), Class 2A or 6g default. Length-under-head is measured from the bearing surface for hex/cap, from the largest face for countersunk. Custom lengths quoted to drawing.
Specialty Screws
TorqBolt produces Gunmetal 903 Set set screws (cup-point, cone-point, dog-point, flat-point, hex-socket DIN 913/914/915/916), shoulder screws (precision-ground shoulder for pivot applications), and self-tapping screws (Type AB, Type 25). All certified per EN 10204 3.1 / 3.2 with optional NACE MR0175 sour-service compliance.
Bronze alloys are copper-based alloys with tin, aluminium, silicon, manganese, or phosphorus alloying additions, each tuned for a specific tribological or environmental envelope. Bronzes deliver excellent bearing properties, marine corrosion resistance, and non-sparking + non-magnetic characteristics — specified for marine fasteners, electrical hardware, oil + gas wellhead components, and industries where sparks must be avoided.
Phosphor bronze (Cu-Sn-P, e.g. C51000, C52400) combines high yield strength + fatigue with seawater corrosion resistance — the standard for marine + spring fasteners. Silicon bronze (Cu-Si, e.g. C65500) is the marine-grade weldable alloy popular for boat fasteners and architectural cladding. Aluminium bronze (Cu-Al, e.g. C95400/C95500/C95800) achieves yield ~310-585 MPa with outstanding seawater + cavitation resistance — the workhorse for marine pump impellers and propeller hub bolting. Gunmetal (Cu-Sn-Zn-Pb, e.g. C90500) is the historic naval bronze for valves and trim. Leaded bronze adds Pb for free-machining + bearing applications.
Bronze fasteners ship per ASTM B98 (rod/bar) and B584 (sand cast) with EN 10204 3.1 / 3.2 certificates covering composition, hardness, and ASTM B66 ammonia stress-corrosion testing where service exposure warrants.
