Captive screw meets the machinery directive
The machinery directive lays down standards that prevent fasteners from coming loose and detached when taking off machine guards and panels. A series of captive screws from Specialty Fasteners & Components (SFC) have been designed to achieve exactly this performance.
Captive screws from SFC are available in thread sizes M2.5 to M10 or imperial equivalents and retained in the panel by snap-in, swage in or threaded grommets giving a flexiblity in installation. They help minimise down time due to lost components and are replaceable if the threads become damaged during use.
There is a wide range of standard items and SFC's Peter Boote says the company can design parts to meet most applications. Boote noted: "When designing in captive screws, you must remember to allow enough space for the screw thread to be free of the nut with the joint closed otherwise the screw will try and wind itself out of the panel." This can be achieved with either with a counter bore in the nut or a stand-off on the panel.
