Captive screws are a very specialized type of screw. You find them in furniture, in computer parts, and in anything that’s produced on assembly lines, including military equipment. As they won’t clog machinery on the assembly lines, they’re deemed to be safer than regular screws. They’re also much quicker to put in place than regular screws and can be put in place at various stages in the manufacture of an item.
Although captive screws originated in industry and are still vitally important there, they’re a big part of the consumer market too. It’s especially prevalent in flat pack furniture. Captive screws are the bolts that fit into holes that have been pre-drilled and turn to grip a screw and hold two pieces of wood in place. The screw can be locked and unlocked with one turn of the screwdriver and allow for speedy assembly or disassembly. This twist-and-lock type of captive screw is the most common but not the only one. Captive screws might also contain nuts or flanges that are used to lock onto another piece of metal or wood, or they might have locking clips.
The aim here is to make everything easy to assemble or take apart so that the job requires as few steps as possible. The shape of the screws for these purposes will often be different, making them easy to identify and also harder to lose. For furniture, they will generally be tightened with an Allen wrench or a small hexagonal wrench rather than with a flat head or Phillips head screwdriver, although there are captive screws that are locked in place with these types of screwdrivers.
Captive screws are used in the computer industry, but here they tend to be soldered to circuit boards, so they’re permanently fixed. They’re easier to put in place than standard screws and are less subjected to pressures that could cause them to loosen.
New Captive Screws
With these it’s possible to snap the screws into place just with pressure from the thumb. For disassembly, the screw is held in place by an aluminum grommet so no parts become loose and vanish. For computers, the newest captive screws maximize thermal conductivity by giving high-load, consistent mechanical fastening. That will remain even regardless of the shock of vibration the device undergoes or even when the thermal chip expands.
Types of Captive Screws
Much as with regular screws, there are many types of captive screws. In some instances, the screws will be manufactured so they can retract or even pivot back. This will prevent workers on an assembly line from hurting themselves on the screws. Be aware that although one captive screw might look like another, they can’t necessarily be substituted due to small differences in the grooves and threading. Much will depend on the application of the captive screws. Anyone who’s tried to use a similar type of captive screw when putting together furniture and had problems will understand this all too well.