What does SEMS mean in screws?

What does SEMS mean in screws?

SEMS are a bolt combination with a permanently attached washer or set of washers. It is also referred to as captivated washers, screw/bolt-washer assemblies or combi bolts. The word SEMS originates from The Illinois Tool Works Inc., who made machines that produced pre-asSEMbled washers and screws.

What is a Square Conical washer?

Square Conical Washer SEMS. Square Conical Washer SEMS are designed to be used on fragile materials (circuit boards) and reduce stress cracking.

How are Sems screws made?

SEMS are created by combing a bolt with a permanently affixed washer. This washer stays in place due to the fact that it is installed on the blank bolt before the thread rolling is conducted. Because the treads are larger than the initial diameter, the washer stays in place without falling loose from the bolt.

How do you make SEMS?

What is truss head screw?

Truss head (or mushroom) screws are characterized by a low, slightly rounded surface and an extra-wide top. Truss head screws have a lower profile than other rounded head screws; thus, they can prevent tampering. Their wide head makes them suited to fasten sheet metal workpieces with large diameter holes.

When would you use a truss screw?

Truss head screws are commonly used to attach cabinets to steel studs. They are also used in electronics items and in applications requiring low clearance above the head. Finally, steel truss head screws are used to assemble metal parts that will be used in humid environments.

What is the difference between conical and double washer SEMs?

Generally, Double Washer Sems are more cost-effective than conical washers, have a greater holding strength. Typically, Double Washer Sems are used in the Electronics Industry, however contact us if you have a specific requirement and we will be glad to assist.

Why use washers with SEMs screws?

To improve the integrity and strength of assemblies, washers are often used along with screws. It was a great leap forward when screws and washers became pre-assembled into the Sems screw.

What are square cone SEMs screws?

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. Made from stainless steel, these screws have good chemical resistance and may be mildly magnetic.

What types of SEMS Screws do you offer?

Our large, in-stock inventory includes steel SEMS screws and stainless steel SEMS screws in a variety of sizes and head styles, including hex, hex washer, and pan head. We also offer a full line of metric SEMS screws.