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Home / Connectors and Fasteners / Black 304 Stainless Steel Smooth Cup Head Socket Screw, Unknurled Cylinder Bolt M2 M3 M4 M5 M6 M8

Attributes

Brand -
Category Industrial Small Parts / Connectors and Fasteners
Origin -
Material Composition 304 Stainless Steel
Finish Color Black
Head Configuration Smooth Cup Head
Drive Mechanism Hex Socket (Allen)
Thread Standard Metric Coarse
Size Range M2, M3, M4, M5, M6, M8
Surface Texture Non-Knurled Smooth
Hardness Level HRC 25-30
Corrosion Resistance High (Indoor/Outdoor)
Package Format Assorted Kit Box

5 reviews

A

Anonymous

Apr 20, 2026

Rating: 5/5

Fast delivery and organized

Came well packaged and organized by size. Made finding the right screw very easy during my build.

A

Anonymous

Apr 16, 2026

Rating: 5/5

Perfect fit for CNC assembly

Used these for my CNC machine assembly. The hex socket fits perfectly without stripping. The black finish looks professional.

A

Anonymous

Feb 13, 2026

Rating: 5/5

Nice black coat

Looks professional on my project. The coating seems durable and hasn't chipped during installation.

A

Anonymous

Feb 12, 2026

Rating: 4/5

Good strength overall

Good strength for the price. One bolt head was slightly rounded but the rest were perfect. Would buy again.

A

Anonymous

Jan 24, 2026

Rating: 5/5

Reliable fasteners

No stripping during installation. The stainless steel quality feels solid and the black oxide finish is even.

5 FAQ

Q: Do you stock these in M10 size?

A: Currently, this listing only supports sizes up to M8. Please check our other listings for larger sizes.

Q: Are these bolts fully threaded?

A: Yes, these specific cup head screws are fully threaded along the shank.

Q: Is the black coating safe for general use?

A: Yes, the black oxide finish is safe for general mechanical and industrial applications.

Q: What hex key size is needed for the M4 screws?

A: Typically, a 2.5mm hex key is required for M4 cup head socket screws.

Q: Can I use these for outdoor projects?

A: Yes, 304 stainless steel offers good corrosion resistance for most outdoor environments.

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