How do bolts work?
drawing of a bolt and hangerA: Specialized bolts have been devised for climbing applications. The bolt fits into a hole drilled into the rock. This is typically done with a hand drill and hammer and takes about half an hour. The bolt is then hammered, threaded, glued, or mechanically secured in the hole. A mechanically secured bolt is one where tightening it causes the shaft to expand in the hole, the most common means of securing. Glue or sealer is often added to prevent water from getting into the bolt hole. Bolts work in conjunction with a bolt hanger. The hanger (image on right) is a small metal plate secured by the shaft of the bolt. This metal plate has a hole in it for a carabiner to pass through.
