Self Cutting / Forming Fasteners
This category includes self-tapping screws, thread-forming screws, spring clips and stamped nuts that anchor into the die casting by cutting into or forming it as they are installed.
- Die cast alloys are relatively soft compared with the hard steel commonly used, and readily accept these fasteners. The use of steel fasteners alerts the designer to determine whether galvanic precautions are required, especially for magnesium-to-steel contact
- Dynacast engineers will work with you to determine retention capabilities, installation forces, and recommended dimensions for the die cast features that will receive the fasteners
- Spring clips and stamped nuts that attach to integral cast studs or posts provide very low cost fastening; they also develop a relatively low retention force. They are usually made of high-strength steel with hard-cutting edges and are installed by pushing or spinning on
- Standard self-tapping screws with cutting action and thread-forming screws that deform metal without removing it work well in die castings. The cost is higher than for spring clips and stamped nuts, but retention capability is greater. The cost is less than for tapped threads because the tapping operation is eliminated, but retention is lower. They won't work as well if repeated removal and reinstallation is anticipated
- In many cases, holes can be cast to the required size. Self-tapping screws with cutting action form chips, so thread-forming fasteners are preferred
