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Cross-Recess-Countersunk-Self-Drilling-Screw-304

Cross Recess Countersunk Self-Drilling Screw (196)

196 products
Cross-Recess-Pan-Head-Self-Drilling-Screw-304

Cross Recess Pan Head Self-Drilling Screw (213)

213 products
Cross-Recess-Pan-Head-Self-Drilling-Screw-with-Washer-304

Cross Recess Pan Head Self-Drilling Screw with Washer (32)

32 products
Hex-Flange-Self-Drilling-Screw-304

Hex Flange Self-Drilling Screw (117)

117 products

What Are Self-Drilling Screws?

Self-drilling screws are easily identified by their tip, which resembles a drill bit. Unlike standard self-tapping screws that require a pre-drilled pilot hole, self-drilling screws cut their own hole through the substrate. They are widely used in roofing, HVAC, and cladding industries to attach metal to metal or metal to wood. We offer various head styles including Hex Washer Head (for high torque) and Countersunk (for flush finishing).

Material Guide: Hardness vs. Corrosion Resistance

Selecting the correct stainless steel grade for self-drilling screws is a trade-off between drilling capacity and rust resistance. Stainless Steel 410 is magnetic and hard, while 304 and 316 are non-magnetic and corrosion-resistant but softer.
Material Grade Steel Type Drilling Capability Corrosion Resistance
SS 410 Martensitic (Hardened) Excellent. Can drill through carbon steel sheets and structural steel. Moderate. Will surface rust over time in outdoor elements without coating.
SS 304 (A2) Austenitic (Soft) Limited. Suitable for drilling aluminum, plastics, or wood. Cannot drill thick steel. High. Standard for outdoor construction.
SS 316 (A4) Austenitic (Soft) Limited. Suitable for aluminum, plastics, or wood. Cannot drill thick steel. Superior. Essential for marine and chemical environments.

Quality Assurance and Documentation

We prioritize the reliability of your connections. To validate the material compositionโ€”especially distinguishing between the magnetic 410 and non-magnetic 304/316 gradesโ€”we provide EN 10204 Type 3.1 Material Test Certificates (MTC) free of charge upon request. Please specify if you need these documents when submitting your order. For critical structural projects, third-party inspection options are available for an extra fee.

Industrial Applications

Stainless Steel 410 screws are the industry standard for metal roofing and assembling steel frames where the screw must penetrate the structure. Stainless Steel 304 and 316 screws are frequently used in the marine industry to attach fittings to fiberglass or aluminum boats, and in solar panel mounting where aluminum racking is used, preventing galvanic corrosion while ensuring longevity.

Frequently Asked Questions

What is the difference between Self-Tapping and Self-Drilling screws?

The key difference is the tip. A self-drilling screw has a drill-bit point that cuts its own hole, eliminating the need for a drill bit. A self-tapping screw has a sharp, pointed tip and usually requires a pre-drilled pilot hole to function correctly. Think of a self-driller as a "drill bit and screw in one."

Why is my Stainless Steel 410 screw magnetic?

This is normal. Stainless Steel 410 is a martensitic steel, which means its metallurgical structure is magnetic. This is different from the austenitic 304 and 316 grades, which are generally non-magnetic. The magnetism of 410 is a side effect of the chemical composition that allows it to be heat-treated for hardness.

Can I use SS 304 self-drilling screws for steel beams?

Generally, no. Because SS 304 is softer than carbon steel, the drill point will likely dull or melt before it penetrates a steel beam. For drilling into steel, you must use hardened SS 410 or specialized Bi-Metal screws. SS 304 self-drillers are best reserved for softer materials like aluminum sheeting or timber.