Attributes

Brand	-
Category	Standard Parts, Components & Industrial Consumables / Screws
Origin	-
Screw Size	M4
Length	120mm
Head Type	Countersunk (Flat Head)
Drive Type	Cross (Phillips)
Material	Carbon Steel
Finish	Black Oxide
Thread Type	Self-Tapping
Hardness Grade	High-Strength Hardened
Standard	National Standard (GB)
Application	Switch Panels, Metal Sheets, General Assembly

6 reviews

Anonymous

Mar 25, 2026

Rating: 5/5

Excellent length and strength

Finding M4 screws at 120mm length locally is impossible. These are high strength and the black finish looks professional on our industrial equipment assemblies.

Anonymous

Mar 24, 2026

Rating: 4/5

Great value for bulk purchase

Bought a box for our workshop. They are consistent in size and thread pitch. One or two had slight cosmetic imperfections on the head, but functionally they are perfect.

Anonymous

Mar 14, 2026

Rating: 5/5

Exactly as described

National standard quality is evident. They fit tight and hold secure in carbon steel frames. Will definitely order again for our next project.

Anonymous

Mar 06, 2026

Rating: 4/5

Good quality, long lead time

The screw quality is excellent and they tap into metal sheets very smoothly. Only giving 4 stars because shipping took a bit longer than expected, but the product itself is solid.

Anonymous

Mar 04, 2026

Rating: 5/5

No stripping issues

I used a power driver on these and was worried about the heads stripping, but the cross drive held up perfectly. Very impressed with the hardness.

Anonymous

Mar 02, 2026

Rating: 5/5

Perfect for heavy-duty electrical boxes

These 120mm screws are exactly what I needed for mounting large switch panels. The hardened steel holds up well without stripping, and the countersunk head sits perfectly flush.

5 FAQ

Q: Can these be used with aluminum sheets?

A: Yes, these self-tapping screws can be used with aluminum sheets. However, since they are hardened steel, care should be taken not to overtighten, which could cause galling in softer aluminum materials.

Q: Are these sold individually or in packs?

A: These screws are typically sold in bulk packs of 50 or 100 units to accommodate industrial and contractor needs. Please check the specific quantity options available at checkout.

Q: Does the 120mm measurement include the head?

A: No, for countersunk (flat head) screws, the 120mm length measurement refers to the total length including the head, measured from the top of the head to the tip of the screw.

Q: Are these screws suitable for outdoor use?

A: While they are made of hardened carbon steel with a black oxide finish, they are best suited for indoor applications. For prolonged outdoor exposure, we recommend applying an additional rust-resistant coating or using stainless steel alternatives.

Q: What size drill bit should I use for pilot holes?

A: For M4 self-tapping screws in metal, a pilot hole is often not required if the material is thin. However, for thicker materials or to ensure precision, a 3.3mm drill bit is recommended for the pilot hole.

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