DIN557 GB39 304 A2-70 Stainless Steel Square Nut Metric Thread M3–M12

DIN557 GB39 304 A2-70 Stainless Steel Square Nut — Metric Thread M3–M12

DIN557 / GB39 304 A2-70 stainless steel square nuts provide anti-rotation performance in T-slot channels, wooden grooves, and aluminium extrusion profiles where a standard hex nut would spin freely. The four-sided geometry locks against the channel walls, allowing the bolt to be tightened from one side without holding the nut. Essential for aluminium extrusion frame assembly, woodworking jigs, and T-slot table workholding.

Key Specifications

Why Choose DIN557 Square Nuts?

• Anti-rotation in channels — square geometry locks against T-slot channel walls; prevents spinning during bolt tightening without rear access
• T-slot compatible — fits standard aluminium extrusion T-slot profiles (2020, 3030, 4040) and woodworking T-track channels
• 304 A2-70 stainless — corrosion-resistant for outdoor, marine, and food processing applications; superior to zinc-plated carbon steel square nuts
• DIN557 standard — internationally specified; compatible with all standard metric coarse thread bolts M3–M12
• M3–M12 range — covers light electronics and 3D printer assembly (M3–M5) through structural T-slot and woodworking (M8–M12)

Typical Applications

• Aluminium extrusion T-slot frame assembly (2020, 3030, 4040, 4080 profiles) — M3, M4, M5, M6
• Woodworking T-track and router table workholding (M6–M12)
• 3D printer frame assembly using aluminium extrusion (M3–M5)
• CNC machine T-slot table workholding and fixture mounting (M6–M12)
• Laser engraver and plasma cutter T-slot bed mounting (M5–M8)
• Jig and fixture T-slot clamping systems (M6–M12)

Compatible With

• Aluminium extrusion T-slot profiles: 2020 (M4/M5), 3030 (M6), 4040 (M8), 4080 (M8) series
• Standard woodworking T-track channels (M6, M8, M10, M12)
• Standard metric coarse thread bolts and cap screws M3–M12
• Spanner / socket: M3=5.5mm, M4=7mm, M5=8mm, M6=10mm, M8=13mm, M10=17mm, M12=19mm AF

Package Contents

• DIN557 square nuts in selected size and quantity (per variant)

Frequently Asked Questions

Q: What aluminium extrusion profile size uses which square nut?

A: 2020 extrusion uses M4 or M5 square nuts; 3030 uses M6; 4040 and 4080 use M8. The nut must fit inside the T-slot channel — check the channel width of your specific extrusion profile before ordering.

Q: Can I use square nuts instead of T-slot nuts in aluminium extrusion?

A: Yes. Square nuts can be used in aluminium extrusion T-slots as an alternative to dedicated T-slot nuts. They provide good anti-rotation performance and are often more economical. Ensure the square nut dimensions match your extrusion’s T-slot channel width.

Q: What is the difference between DIN557 and DIN562 square nuts?

A: DIN557 is the standard (full height) square nut. DIN562 is the thin (low profile) square nut with reduced height. Use DIN557 for standard fastening; use DIN562 where nut height is restricted or a lower profile is required.