Which bolt type is used with coil inserts?

• A. Self-cleaning threaded bolts
• B. A standard hex bolt
• C. A lag bolt
• D. A wood screw

Answer: (A)

Coil inserts provide durable, internal threads inside a material. The bolt that goes into them should engage cleanly and fully without dragging debris into the insert. Self-cleaning threaded bolts are designed to scrape away debris from the threads as they are driven, ensuring a smooth, proper engagement with the coil insert. This helps prevent binding or cross‑threading and preserves the insert’s threaded integrity. Standard hex bolts, lag bolts, or wood screws don’t have this cleaning action and aren’t specifically matched to coil inserts, so they’re not the best choice for this application.