Also known as Sems screws, these screws have a permanently attached but freely rotating tooth lock washer that bites into the mating surface for vibration resistance.

With a tensile strength of 180,000 psi, these alloy steel screws are among the strongest we carry. They are stronger than Grade 8 steel screws and more than two and a half times stronger than stainless steel screws with split lock washer. The split lock washer helps to resist vibration.

Sharp internal teeth dig into surfaces to resist large amounts of vibration, while the smooth outside edge provides a finished look. Also known as Sems screws, the washer rotates freely but is permanently attached.

Made from stainless steel, these metric screws have good chemical resistance and may be mildly magnetic. The washer has sharp internal teeth that dig into surfaces to resist large amounts of vibration while the smooth outside edge provides a finished look. Also known as Sems screws, the washer rotates freely but is permanently attached.

These metric stainless steel screws have good chemical resistance and may be mildly magnetic. A curved washer protects delicate surfaces while providing constant tension. Also known as Square Cone Sems screws, the washer rotates freely but is permanently attached.

A zinc plating provides mild corrosion resistance.

These metric screws have a washer with sharp external teeth that dig into surfaces for maximum holding power and vibration resistance. Also known as Sems screws, the washer rotates freely but is permanently attached.

These metric stainless steel screws have good chemical resistance and may be mildly magnetic. All have a washer with sharp external teeth that dig into surfaces for maximum holding power and vibration resistance. Also known as Sems screws, the washer rotates freely but is permanently attached.

When compressed, the split lock washer flattens to add tension and prevent loosening from small amounts of vibration. Also known as Sems screws, the washer rotates freely but is permanently attached.