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Home / Screws / 304 Stainless Steel Countersunk Internal Hex Screw, Flat Head Flat Cup Bolt Screw M2 M3 M4 M5 M6 M8 M10 M12 M16

Attributes

Brand -
Category Standard Parts, Components & Industrial Consumables / Screws
Origin -
Material 304 Stainless Steel
Head Style Flat Head (Countersunk)
Drive Type Internal Hex (Allen)
Thread Standard Metric Coarse
Available Sizes M2, M3, M4, M5, M6, M8, M10, M12, M16
Finish Polished Silver
Corrosion Resistance High (Suitable for indoor and outdoor use)
Tensile Strength Standard Grade A2-70
Package Contents Assorted Kit or Bulk Pack options
Origin Jiangsu, China

6 reviews

A

Anonymous

Mar 30, 2026

Rating: 4/5

Good value, fast shipping

Ordered the M4 and M5 sizes. They look solid and have a nice finish. One screw had a slightly imperfect head, but the rest of the batch was flawless. Would buy again.

A

Anonymous

Mar 23, 2026

Rating: 4/5

Solid hardware

Very sturdy screws. The countersunk head sits perfectly flush with the surface. Just make sure you have the correct Allen key size, as tolerances are tight.

A

Anonymous

Mar 20, 2026

Rating: 5/5

Perfect fit for my project

These screws are exactly what I needed for assembling my aluminum frame. The internal hex drive is precise and didn't strip even under high torque. Great quality stainless steel.

A

Anonymous

Mar 18, 2026

Rating: 5/5

Excellent corrosion resistance

Using these for an outdoor garden structure. After three months of rain and sun, there is absolutely no sign of rust. Highly recommend for exterior applications.

A

Anonymous

Mar 02, 2026

Rating: 5/5

Great assortment

Bought the mixed kit to keep in the toolbox. Having various sizes from M2 to M8 on hand is super convenient. The packaging kept them organized and rust-free.

A

Anonymous

Mar 02, 2026

Rating: 5/5

Professional grade quality

I run a small repair shop and we go through a lot of fasteners. These 304 stainless screws are consistent in size and thread pitch. No issues with cross-threading.

5 FAQ

Q: Are these screws suitable for marine environments?

A: While 304 stainless steel offers good corrosion resistance, for constant exposure to saltwater, we recommend our 316 stainless steel series for superior protection.

Q: Can these be used with aluminum sheets without causing galvanic corrosion?

A: Stainless steel can cause galvanic corrosion when in direct contact with aluminum in wet conditions. We suggest using a plastic washer or anti-seize compound as a barrier.

Q: Do you sell matching nuts for these bolts?

A: Yes, we carry matching 304 stainless steel hex nuts and washers in all corresponding sizes. Please check the 'Related Products' section on the product page.

Q: What is the thread pitch for the M6 size?

A: The M6 screws feature a standard coarse thread pitch of 1.0mm, adhering to ISO metric standards.

Q: What Allen key size is required for the M8 screw?

A: For the M8 internal hex flat head screw, you will need a 6mm Allen key (hex wrench) for proper installation.

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