Grub Screws & Set Screws — Hex Socket Set Screws for Shaft Retention

Grub screws (set screws) are fully threaded, headless fasteners that apply direct bearing force against a shaft or surface — the primary fastener for locking collars, couplings, sprockets, and pulleys to shafts. AIMS Industrial sells grub screws in metric Grade 12.9 alloy steel (black) and 316 stainless steel with cup point, flat point, and cone point tips in a full range of metric sizes.

Grub Screws We Stock

• Grade 12.9 Cup Point Grub Screws: Grade 12.9 alloy steel cup point grub screws with hexagonal socket drive (DIN 916/ISO 4029) — the standard grub screw for hub-to-shaft retention in power transmission applications. The cup point indents into the shaft surface, providing positive anti-rotation engagement without full penetration.
• Grade 12.9 Flat Point Set Screws: Flat point grub screws for applications where shaft surface marking must be avoided — the flat point distributes load without indenting. Used on finished shaft surfaces, hardened shafts, and applications where the grub screw is frequently adjusted or repositioned.
• Cone Point Set Screws: Cone point set screws for permanent installation requiring maximum anti-rotation security — the cone point penetrates the shaft surface, providing mechanical keying. Not suitable for applications requiring future disassembly without shaft regrinding.
• 316 Stainless Steel Grub Screws: 316 ss grub screws for stainless machinery, food processing equipment, and corrosive environments where alloy steel would corrode or cause contamination concerns.
• Metric Size Range M3 to M20: Grub screws in M3 through M20 covering all common shaft collar and hub applications — M3 to M6 for small diameter shafts and instrumentation; M8 to M12 for standard power transmission; M16 to M20 for heavy industrial couplings.

Grub Screw Selection & Tightening Guide

• Tightening Torque is Critical: Grub screws transmit load through friction between the shaft and hub — insufficient preload allows hub rotation on the shaft. Apply the manufacturer's specified tightening torque using a calibrated hex key or torque screwdriver; do not over-torque as this fractures the hex socket.
• Grade 12.9 vs Standard Grade: Grade 12.9 provides significantly higher tensile strength than Grade 8.8 in the same thread form — allowing higher clamping force for the shaft retention application. Always use Grade 12.9 or the grade specified in the hub or coupling manufacturer's documentation.
• Locking the Grub Screw: In high-vibration applications, treat the grub screw thread with medium-strength thread locker (Loctite 243) before installation — preventing vibration loosening without galling the thread during future removal.

Australian Business, Local Supply: As a proudly Australian business since 1988, we stock locally and work with trusted local Australian manufacturers and distributors to ensure fast, reliable supply.

Expert Support: Need help buying the right product for your application? Contact our team for application-specific advice or request a quote.

See our full fasteners range including hex set screws, button head socket screws, and hex set bolts.