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In a folding knife, the blade swings around a pivot at one end of the handle. When open, it is locked into position. When closed, it is nestled inside the handle scales for safe carry in a pocket or pouch. From there, folding knife design varies widely. Much of a folder’s design is centered on its greatest inherent weakness—the reliability of the lockup when open. Other aspects include speed of opening, beautiful handles, and sleek interior parts.

Manual folders that require the user to open the blade are still the most common type. Assisted-opening folders, in which spring mechanisms complete the opening process once the blade is partially opened, have joined the scene in recent years. Automatic folders—in which a spring mechanism exerts opening pressure on the blade with the mere press of a button—are growing in popularity as more states loosen knife restrictions.

The advent of the pocket clip ushered in a new way of thinking about carrying knives, complete with its own acronym: EDC, for “everyday carry.” EDC knives are highly functional models designed to be clipped to a pocket or belt. Fixed-blade and folding knives share plenty of common ground, but in many respects they’re different species entirely. Here’s the engineering behind the flick.

Illustration of a folding knife
Courtesy of Weldon Owen
  1. POCKET CLIP A metal clip that enables the user to clip the knife to a pocket for comfortable carry and quick deployment.
  2. BACK SPACER A strip of metal or tough synthetic material, such as G10, that spans the interior of the two sides of the knife handle. Metal back spacers are sometimes intricately filed.
  3. OPEN FRAME An open-frame folder has no back spacer. It can be cleaned easily, but the blade edge is exposed to loose change, keys, and other hard objects in a pocket.
  4. STANDOFF A metal pillar that provides the proper interior spacing for operation of the knife.
  5. LINER Thin plates, typically of steel or titanium, on the interior face of the handle slabs. The liners reinforce the handle; on liner-lock designs they serve as the locking mechanism.
  6. THUMB STUD A metal stud or opening near the knife’s pivot. By pressing or hooking a thumb onto the stud or opening, the blade can be swiveled open with one hand. Thumb studs are typically found on both sides of the blade to allow for ambidextrous opening.
  7. PIVOT The joint around which the blade swings. On some knives, the pivot can be manipulated to adjust the tension of the action.
  8. LANYARD HOLE Allows for the attachment of parachute cord or other cordage.
  9. FLIPPER A trigger like protrusion on the blade that allows the knife to be flipped open with a finger. Not found on all knives.

This article was adapted from Field & Stream’s Total Camping Manual.